Pollution

Inflammation Pollution

Plastic pollution isn’t just an environmental issue—it may also pose hidden risks to human health. Growing evidence suggests that tiny plastic fragments, known as microplastics and nanoplastics, could contribute to chronic diseases by causing inflammation and oxidative stress. A recent study found that people living in coastal U.S. counties with the highest levels of marine microplastics were 18% more likely to have type 2 diabetes, 7% more likely to have coronary artery disease, and 9% more likely to have a stroke than those in counties with low levels.

To investigate whether marine microplastics might affect human health on a population level, researchers analyzed ocean surface water samples collected within 200 nautical miles of the U.S. coastline. Based on the average concentration of microplastics in adjacent waters, they classified coastal counties as low, medium, high, or very high. Then, they assessed the prevalence of type 2 diabetes, coronary artery disease, and stroke in each group, adjusting for differences in age, sex, healthcare access, and socioeconomic factors.

Counties with very high levels of marine microplastics had notably higher rates of all three cardiometabolic diseases than counties with low levels. The prevalence of type 2 diabetes was 18% higher, coronary artery disease was 7% higher, and stroke was 9% higher, even after accounting for other risk factors. These patterns were strongest in counties along the Gulf of Mexico, where microplastic levels and disease rates were generally higher than those along the Atlantic or Pacific coasts.

These findings suggest a possible link between environmental plastic pollution and cardiometabolic health. Microplastics and nanoplastics are pervasive in the environment. Learn how to reduce your exposure in Aliquot #122: How to Limit Microplastic Exposure.

Polystyrene nanoplastics accumulate in body tissues and trigger gut health disruption by altering gut microbial populations, impairing mucus production, and interfering with proteins maintaining the gut barrier. www.nature.com

Gut Pollution

Nanoplastics are emerging as a new concern in environmental and human health due to their capacity to interact with biological systems at the cellular level. Their small size allows them to penetrate tissues and potentially disrupt key physiological processes, particularly in the gut. A recent study in mice found that polystyrene nanoplastics can disrupt gut bacteria, weaken the intestinal barrier, and trigger molecular changes that may have far-reaching effects on health.

Researchers exposed mice to oral doses of polystyrene nanoplastics four times a week for 12 weeks and used fluorescent labels to track where the particles went. Then, they examined the animals' gut tissue, analyzed changes in their gut microbiota, and evaluated changes in extracellular vesicles—tiny membrane-bound structures released by gut cells and bacteria that facilitate intercellular communication.

The researchers found that nanoplastics accumulated in the gut, liver, and other tissues for up to 48 hours. Mice exposed to nanoplastics gained more weight than unexposed mice—about 28% more—despite no differences in liver or fat tissue mass. Nanoplastic exposure altered gut microbial populations, disrupted mucus production, and interfered with proteins maintaining the gut barrier.

These findings suggest that nanoplastics weaken the gut’s defenses by altering the microbiome and changing how gut cells communicate through extracellular vesicles. Over time, this disruption could increase vulnerability to disease, even without obvious inflammation or liver damage. Learn more about micro- and nanoplastics in our overview article.

Microplastics found in ovarian follicular fluid of nearly 80% of women undergoing fertility treatment, potentially disrupting hormone regulation, impairing egg maturation, and altering embryo development. www.sciencedirect.com

Pregnancy Pollution

Plastic contamination has become pervasive, with microplastics—microscopic plastic particles—now detected in most human tissues. A recent study found microplastics in the follicular fluid of women undergoing fertility treatment, raising new concerns about how these contaminants might affect human reproduction.

Researchers collected follicular fluid samples from 18 women receiving assisted reproductive treatment. To detect and characterize plastic particles smaller than 10 micrometers, they used scanning electron microscopy paired with energy-dispersive X-ray spectroscopy—an advanced technique that identifies materials based on their composition.

They found microplastics in nearly 80% of the samples (14 out of 18), with an average concentration of more than 2,000 particles per milliliter. On average, particles measured about 4.5 micrometers in diameter. They did not identify an association between microplastic concentration, fertilization, miscarriages, and live birth. However, higher microplastic concentrations were associated with higher levels of follicle-stimulating hormone, a key marker of ovarian function.

These findings indicate that microplastics accumulate in human ovarian follicles. The investigators proposed that the lack of association between microplastics and aspects of reproductive health may have been due to the small study size (only 18 women), especially in light of animal evidence indicating that microplastics disrupt hormone regulation, impair egg maturation, and alter embryo development. Learn more about the effects of microplastics on the reproductive system in this episode featuring Dr. Rhonda Patrick.

The air in children's sleeping areas harbors high chemical pollutant levels, potentially increasing young children's exposure to toxic compounds. pubs.acs.org

Sleep Development Pollution

The air around a child’s bed may carry more chemical pollutants than the bedroom itself. A recent study suggests sleeping spaces are a key source of toxic exposure for young children.

Researchers collected air samples from the sleeping areas and bedrooms of 25 children between 6 months and 4 years old living in Canada. They also tested the children’s mattresses for chemical emissions, looking for three types of compounds: phthalates (used to soften plastics), flame retardants, and UV filters (used in dyes and textiles). These chemicals belong to a group called semivolatile organic compounds, or SVOCs, which can escape from products and linger in air, dust, and on surfaces.

The researchers detected nearly 30 different chemicals in each of the three sampling locations—bedroom air, sleeping area air, and mattresses. The air in the sleeping area had higher chemical levels than the surrounding bedroom, confirming that bedding and other nearby items were likely contributing to children’s exposure. In many cases, the mattresses themselves released higher amounts of certain phthalates and flame retardants, while bedding appeared to be a major source of flame retardants.

These findings suggest that young children face increased chemical exposure while they sleep, a substantial concern given how much time they spend in their sleeping environments. The investigators proposed that parents reduce exposure by regularly washing bedding and sleepwear, as fabrics tend to trap airborne chemicals. Furthermore, some textiles can also release chemicals, so having fewer items in the bed is beneficial.

Microplastics in wastewater may drive a 171-fold increase in antibiotic resistance in E. coli. journals.asm.org

Antibiotics Pollution

Microplastics may be more than environmental pollutants—they could contribute to the rise of drug-resistant bacteria. These tiny plastic fragments persist in wastewater, providing surfaces where bacteria congregate, form biofilms, and exchange genetic material that enhances antibiotic resistance. A recent study found that Escherichia coli cultured on microplastics were 171 times more resistant to the antibiotic ciprofloxacin than those grown on glass.

Researchers exposed E. coli to different types of microplastics—polyethylene, polystyrene, and polypropylene—at varying concentrations and sizes. They measured the bacteria’s survival rates and assessed whether they developed resistance to four common antibiotics: ampicillin, ciprofloxacin, doxycycline, and streptomycin. They also compared bacterial behavior on microplastics versus glass to determine how different surfaces influenced biofilm formation.

Bacteria attached to microplastics formed stronger biofilms and exhibited higher antibiotic resistance than those grown on glass. The water-repellant nature of the plastics, combined with their ability to attract and retain other substances, likely contributed to this effect. Bacteria grown in the presence of antibiotics and microplastics showed considerably greater resistance, with those exposed to ciprofloxacin displaying up to 171 times greater resistance and other antibiotics showing increases of up to 75 times.

These findings suggest that microplastics serve as breeding grounds for antibiotic resistance, potentially increasing the risk of persistent infections in environmental and healthcare settings. Addressing microplastic pollution may be crucial in slowing the spread of drug-resistant bacteria. Learn how to limit your exposure to microplastics in this episode featuring Dr. Rhonda Patrick.

High exposure to plastics, such as those in disposable takeout containers, is associated with a 13% greater risk of heart disease, potentially through changes to gut bacteria and increased inflammation. www.sciencedirect.com

Pollution Environment Cardiovascular

The environment plays a decisive role in heart health, with factors like air pollution, diet, and chemical exposures influencing cardiovascular disease risk. As plastic production and waste continue to rise, concerns about its effects on human health are increasing. A recent study found that frequent exposure to plastics, including those from disposable takeout containers, is associated with a 13% higher likelihood of developing cardiovascular disease.

Researchers surveyed more than 3,000 people about their plastic exposure and heart health. They also provided rats with water that had been in contact with disposable plastic takeout containers at high temperatures for varying lengths of time. After three months, they analyzed the rats' heart tissue, blood markers, and gut bacteria to assess changes.

They found that people with high plastic exposure had a 13% greater risk of congestive heart failure than those with lower exposure. In the rats, plastic exposure altered gut bacteria and increased markers of oxidative stress and inflammation in the heart. The structural changes observed in heart tissue suggest potential long-term damage.

These findings suggest that plastic exposure increases the risk of heart disease and highlight the need to reduce exposure. Learn how to reduce your exposure to plastics and microplastics in this episode featuring Dr. Rhonda Patrick.

Microplastics in the bloodstream may obstruct tiny blood vessels in the brain, impairing blood flow and causing neurological disorders, according to a recent study in mice. www.science.org

Brain Pollution Neurodegeneration

Microplastics are everywhere in the environment—from the water we drink to the air we breathe. Scientists have found these tiny plastic particles in human blood, organs, and even the brain, raising concerns about their potential health effects. A recent study in mice found that microplastics in the bloodstream can obstruct tiny blood vessels in the brain, impairing blood flow and driving neurological disorders.

Researchers injected fluorescently labeled microplastics into mice and observed how the particles traveled through brain capillaries. In particular, they focused on how immune cells interacted with microplastics and whether they contributed to vascular blockages.

They found that immune cells engulfed microplastics, driving unintended consequences. These microplastic-laden cells clogged capillaries in the brain, reducing blood flow and triggering neurological impairments in the mice. The blockages resembled tiny blood clots, highlighting a previously unknown way microplastics could harm brain function.

These findings suggest that microplastics contribute to brain dysfunction by indirectly disrupting blood flow rather than directly penetrating brain tissue. Learn more about microplastics and brain health in this episode featuring Dr. Rhonda Patrick.

Exposure to synthetic PFAS chemicals in drinking water may increase the risk of certain cancers by up to 33%. www.nature.com

Cancer Pollution

Nearly 2 million people in the U.S. were diagnosed with cancer in 2023, and exposure to polyfluoroalkyl substances (PFAS) may be a contributing factor. These synthetic chemicals, found in food packaging, household products, and personal care items, are known endocrine disruptors that persist in the body and increase the risk of cancer, liver damage, and immune system dysfunction. Recent research suggests that PFAS in drinking water may elevate the risk of cancers affecting the mouth and throat as well as the digestive, endocrine, and respiratory systems.

Researchers collected data on PFAS levels in U.S. public drinking water systems and county-level cancer rates from 2016 to 2021. Then, using statistical analysis, they estimated the number of cancer cases attributable to PFAS exposure.

They found that PFAS in drinking water was associated with increased cancer rates in the digestive, endocrine, respiratory, and mouth/throat systems, with risk increases of up to 33%. Among men, PFAS exposure was linked to higher rates of leukemia and cancers of the urinary tract, brain, and soft tissues, while among women, it was associated with thyroid, mouth/throat, and soft tissue cancers. Their analysis estimated that PFAS in drinking water contributes to approximately 4,600 to 6,900 new cancer cases annually, depending on the dataset used.

These findings highlight the potential risks of PFAS exposure. Because PFAS are present in plastics, microplastics are a significant source of exposure. Learn more about PFAS and microplastics in our overview article.

Glyphosate exposure in mice accelerates Alzheimer's disease processes, with the herbicide's metabolites persisting in brain tissue six months after initial exposure. jneuroinflammation.biomedcentral.com

Brain Alzheimer's Dementia Pollution

Glyphosate, a widely used herbicide, has been linked to widespread inflammation and neuronal damage in the brain. A recent study in mice found that glyphosate and its primary metabolite, aminomethylphosphonic acid, persist in brain tissue for months after exposure, potentially contributing to neurodegenerative changes.

Researchers exposed ordinary mice and mice prone to developing Alzheimer’s to varying doses of glyphosate daily for 13 weeks. Six months later, they examined the animals' brain tissues for lingering glyphosate, metabolites, and key markers of Alzheimer’s pathology, including amyloid-beta plaques, tau tangles, and inflammation.

They discovered that glyphosate’s primary metabolite remained in brain tissue even after six months of non-exposure. Glyphosate-exposed Alzheimer’s-prone mice had lower survival rates, more difficulty in spatial memory tasks, and increased markers of Alzheimer’s pathology, including larger and more numerous amyloid-beta plaques and higher levels of phosphorylated tau protein. Both groups of mice exhibited persistent inflammation in their brains and blood.

These findings suggest that glyphosate exposure may contribute to long-lasting brain changes, accelerating processes involved in Alzheimer’s disease. Learn how to mitigate exposures to environmental toxins like glyphosate in this Aliquot featuring Drs. Dale Bredesen, Michael Snyder, and Rhonda Patrick.

Frequent use of personal care products, such as fragrances and nail products, raises 'forever chemical' levels by 10% to 20% during pregnancy and breastfeeding. www.sciencedirect.com

Pregnancy Pollution Breast Milk

Personal care products like makeup, hair treatments, and nail polish often contain per- and poly-fluoroalkyl substances (PFAS). These compounds—often called “forever chemicals"—are linked to serious health risks, including cancer, heart disease, and immune dysfunction. A recent study found that using certain personal care products during pregnancy and breastfeeding raises PFAS levels in the body, exposing developing infants to these toxic compounds.

Researchers analyzed data from nearly 2,000 women in the Maternal-Infant Research on Environmental Chemicals Study to examine how personal care product use affects PFAS concentrations in blood plasma during pregnancy and in breast milk postpartum. Participants reported how often they used eight personal care products, including nail polish, hair sprays, and fragrances, throughout pregnancy and after delivery. The researchers compared personal care use to PFAS levels in blood and breast milk samples collected at specific points.

They found that using certain products frequently—such as daily fragrances or weekly nail care products—was associated with PFAS levels 10% to 20% higher in blood during early pregnancy. Similarly, mothers who used permanent hair dye shortly after delivery had 15% to 20% higher PFAS levels in their breast milk. These patterns were consistent across multiple personal care product categories and for PFAS chemicals known to persist in the body for years.

These findings suggest that personal care products increase PFAS exposure during pregnancy and breastfeeding. PFAS are also found in plastics, which can break down into microplastics and enter the human body. Learn more about microplastics and PFAS exposure in this episode featuring Dr. Rhonda Patrick.

Exposure to fine particulate matter in air pollution more than doubles the risk of developing eczema. journals.plos.org

Inflammation Pollution Skin Oxidative Stress

Eczema, a chronic inflammatory skin condition, affects roughly 10% of people in the United States. Evidence suggests that environmental factors, including air pollution, influence the risk of developing eczema. A recent study found that exposure to fine particulate matter (PM2.5), a key component of ambient air pollution, more than doubles the risk of eczema.

Researchers drew on data from adults enrolled in the All of Us Research Program. They compared people with eczema to those without, linking their zip codes to average annual PM2.5 concentrations. Then, they analyzed the relationship between PM2.5 levels and eczema while adjusting for factors like demographics, smoking, and other skin conditions.

They found that people with eczema were exposed to higher levels of PM2.5 than those without eczema. People with eczema lived in areas with about 2% higher PM2.5 concentrations, and the risk of eczema increased considerably with higher pollution levels. The odds of having eczema were more than twice as high (158%) in areas with the highest PM2.5 concentrations, even after accounting for smoking and other health conditions.

These findings suggest that air pollution contributes to the development of eczema. Given that PM2.5 can infiltrate the skin and contribute to skin barrier dysfunction, oxidative stress, and inflammation, addressing air pollution could be a key strategy for preventing and managing eczema. Sulforaphane, a bioactive compound derived from broccoli, promotes the excretion of air pollutants. Learn more in this clip featuring Dr. Jed Fahey.

Exposure to benzyl butyl phthalate, a common plastic additive in everyday items, was found to cause extensive reproductive cell disruption and DNA damage. journals.plos.org

Metabolism Inflammation DNA Damage Pollution Environment Genome

The risks of everyday plastics may go beyond environmental concerns, affecting our reproductive health on a cellular level. Benzyl butyl phthalate (BBP), a common plastic additive found in toys, cleaning products, food packaging, and cosmetics, has been linked to reproductive and developmental impairments. A recent study in worms found that BPP induced abnormalities in chromosome segregation and increased cell death in reproductive cells.

Researchers exposed C. elegans, a type of roundworm, to four different concentrations of BBP: 1, 10, 100, and 500 micromolar. Then, they measured the chemical’s effects on the worms' chromosomes and cell structure while tracking its metabolism into two primary byproducts: monobutyl phthalate and monobenzyl phthalate.

They found that exposure to 10 micromolar BBP induced considerable cellular disruption, increasing germ cell apoptosis, abnormalities in chromosome structure, and elevated levels of DNA damage throughout the reproductive tissues. The compound also triggered increased oxidative stress and affected critical genes involved in cell cycle progression and oxidative metabolism.

These findings suggest that BBP exposure profoundly affects reproductive health by impairing the cellular processes necessary for healthy chromosome segregation and genomic stability. A person’s phthalate burden may contribute to poor metabolic function, inflammation, and cognitive dysfunction. Learn how sauna use induces substantial sweat losses, promoting the excretion of toxic compounds like BBP.

Frequent use of common household chemicals—including fluoride-based anti-caries agents, air fresheners, and disinfectants—increases the risk of cognitive decline in older adults. pubmed.ncbi.nlm.nih.gov

Brain Aging Dementia Pollution Dental

Cognitive decline—especially among older adults with dementia—can profoundly affect a person’s quality of life and increase their dependency on others. Evidence suggests that environmental exposures influence the risk of dementia. A recent study found that certain household chemicals, widely used for personal hygiene, cleaning, and disinfecting, may pose an unexpected risk for cognitive decline** in older adults.

Researchers analyzed data from a large cohort study of adults over 65. They evaluated how frequently the participants used eight common household chemicals, including insecticides, air fresheners, and disinfectants, and then examined whether these products were linked to declines in cognitive function.

They found that frequent use of anti-caries agents raised the likelihood of developing cognitive decline by 68%, while frequent use of air fresheners increased it by 148%, and disinfectants raised it by 40%. In general, more frequent chemical use was linked with worsening cognitive function.

Anti-caries agents prevent or reduce the development of dental caries, also known as cavities or tooth decay. Common anti-caries agents include fluoride mouth rinses, toothpaste formulations, and dental varnishes or sealants. Air fresheners contain various indoor pollutants, including phthalates and benzene. When these substances react with ozone, they create harmful byproducts that can harm the central nervous system. Sulforaphane, a bioactive compound derived from broccoli, boosts the excretion of pollutants like benzene. Learn more in this clip featuring Dr. Jed Fahey.

Higher exposure to 'forever chemicals'—synthetic substances pervasive in our environment—is linked to decreased kidney function in young adults, potentially driven by gut bacteria and metabolite changes. www.sciencedirect.com

Gut Microbiome Pollution

More than 10% of people worldwide have chronic kidney disease, a debilitating condition that progressively impairs the kidneys' capacity to filter waste and excess fluid from the blood. Evidence suggests that toxic exposures increase kidney disease risk. A recent study found that higher exposure to PFAS—so-called “forever chemicals"—was linked with decreased kidney function in young adults, potentially mediated by gut bacteria and metabolite changes.

The study involved 78 young adults at high risk for metabolic disease. Researchers measured their baseline PFAS levels, gut bacterial composition, and blood metabolite profiles. Then, they assessed the participants' kidney function.

They found that for each incremental increase in PFAS exposure, kidney function declined by roughly 2.4%. Shifts in specific gut bacteria and their metabolites, such as lower levels of Lachnospiraceae and increased levels of metabolites, explained up to half of the association between PFAS and reduced kidney function.

These findings suggest that PFAS contribute to kidney damage by disrupting gut health and metabolic processes. PFAS, short for per- and polyfluoroalkyl substances, are synthetic chemicals widely used in consumer products for their water- and stain-resistant properties. Microplastics often contain PFAS that can leach into the environment and accumulate in the body. Learn more about microplastics and PFAS exposure in this episode featuring Dr. Rhonda Patrick.

Flame retardants used in electronics are found in up to 85% of black plastic household items, including kitchen utensils and toys—an unintended consequence of recycling. pubmed.ncbi.nlm.nih.gov

Cancer Pollution

Flame retardants commonly used in electronics carry considerable health risks, from carcinogenicity to endocrine disruption. Despite their harmful effects, these chemicals are often recycled into household items, including kitchen utensils, toys, and food packaging. A recent study found that black plastic household products may contain flame retardants, particularly those derived from recycled electronic products.

Researchers screened 203 black plastic household products for bromine, a compound used in many flame retardants. They further analyzed products with bromine concentrations higher than 50 parts per million (ppm) for specific flame retardants and plastic types, such as acrylonitrile butadiene styrene and high-impact polystyrene, both commonly used in electronics.

They found that 85% of the analyzed products contained flame retardants, with concentrations as high as 18,600 ppm, or as much as 22,800 milligrams per kilogram. Notably, a banned compound called decaBDE (and its replacement) was found in many household items. Plastics typically used in electronics, such as polypropylene, contained much higher levels of these chemicals than other types.

These findings suggest that current recycling practices introduce hazardous flame retardants into everyday plastic household products, raising concerns about unintentional exposure to these toxic compounds. As these plastic items degrade, they contribute to the growing problem of microplastics, which can carry harmful chemicals like flame retardants into the environment and the food chain, further amplifying health risks. Learn more about microplastics in this video featuring Dr. Rhonda Patrick.

Microplastic particles inhaled by pregnant rats can accumulate in the tissues of their offspring, revealing a potential pathway for generational plastic contamination. www.sciencedirect.com

Pregnancy Development Pollution

Airborne microplastic particles may be doing more than just floating in the air—they could be making their way into future generations. A recent study found that micro- and nanoplastic particles can accumulate in the tissues of offspring after mothers inhale them during pregnancy.

Researchers assigned pregnant rats to one of two groups. They exposed one group to airborne polyamide-12 micro- and nanoplastics for about four hours on ten days during pregnancy—roughly equivalent to 120 minutes per day during a human pregnancy—while the other group received no exposure and served as a control group. Polyamide-12 is used in clothing, other textiles, kitchen items, carpets, and automotive products. After the pups were born, the researchers collected tissue samples from the two-week-old pups' lungs, liver, kidneys, heart, and brain to see if the particles persisted.

They found that the micro- and nanoplastic particles were present in the tissues of all the pups whose mothers had inhaled them but found no particles in the control group. These findings confirm that the particles can migrate from the respiratory system, pass through the placenta, and remain in the tissues of the young even after birth.

These findings suggest that exposure to micro- and nanoplastics during pregnancy can promote their accumulation in offspring, raising concerns about their long-term effects on health. Microplastic particles are smaller than 5 millimeters, while nanoplastics are even tinier—less than 1 micrometer in size. These particles often form when larger plastic items break down due to physical wear, heat, or exposure to sunlight. Micro- and nanoplastic particles are ubiquitous environmental pollutants found in air, water, soil, and food. Learn more about microplastics in our overview article.

Exposure to 'forever chemicals,' commonly found in plastics, is linked to 80 minutes less sleep per night and increased sleep disturbances. www.sciencedirect.com

Sleep Pollution

Many people find getting a good night’s sleep challenging, and some research suggests that chemicals like per- and poly-fluoroalkyl substances (PFAS), known as “forever chemicals,” could be part of the problem. A recent study found that PFAS exposure is linked to shorter sleep duration and increased sleep disturbances.

Researchers measured PFAS levels and proteins related to metabolism and inflammation in the blood of 136 healthy young adults. They asked the participants about their sleep duration, sleep disturbances, and sleep-related impairments.

They found that, on average, those with the highest PFAS levels in their blood slept roughly 80 minutes less per night than those with the lowest levels. Participants with elevated PFAS levels reported more trouble falling and staying asleep, frequent awakenings, and daytime fatigue.

The researchers also found that specific proteins—11-beta-dehydrogenase isozyme-1 and cathepsin B—might participate in PFAS-driven sleep disruption. 11-beta-dehydrogenase isozyme-1 regulates cortisol, influencing metabolism and stress responses, while cathepsin B breaks down proteins, supporting immune functions such as antigen presentation and inflammation.

These findings suggest that PFAS exposure disrupts sleep by altering metabolic and immune pathways. PFAS are principal components of plastic, which can break down and enter the environment as microplastics. Consequently, microplastics may be a major contributor to PFAS exposure. Learn more about microplastics and PFAS exposure in this episode featuring Dr. Rhonda Patrick.

More than 3,600 food-contact chemicals used in packaging and storage detected in humans, including several toxic substances associated with cancer, fertility issues, and hormone disruption. www.nature.com

Cancer Bisphenol A Pollution Sauna

Despite the perceived safety of the U.S. food supply, many chemicals used in food packaging and storage may be hazardous. In fact, food scientists have found that more than 1,800 food-contact chemicals migrate into foods—many of which have never undergone toxicity testing. New research demonstrates that more than 3,600 of these toxic compounds have been detected in humans.

Researchers compared a list of more than 14,000 known food-contact chemicals to five major biomonitoring programs and several databases that track chemicals in the human body. They then prioritized chemicals frequently found in food packaging and examined evidence for their presence in humans.

They found that 3,601 of these chemicals have been detected in humans. Of these, 194 were identified in biomonitoring programs, 80 of which carry a high toxicity risk. They also confirmed that 63 of 175 chemicals of concern were present in the human body, and most lacked safety data.

These findings suggest that human exposure to food-contact chemicals is widespread, highlighting the need for stricter safety regulations. Many food-contact chemicals include bisphenol A, phthalates, and other toxic substances that promote cancer, impair fertility, and disrupt hormone signaling. Although many of these compounds accumulate in the body over time, some are preferentially excreted in sweat. Learn how sauna use promotes sweating, helping the body rid itself of some toxic substances.

Children exposed to skincare lotions and oils have higher urinary phthalate levels—known endocrine disruptors—even when products are labeled "phthalate-free." ehp.niehs.nih.gov

Pollution Skin

The lotion you apply to your child’s skin might do more harm than good, according to new research. Children are especially vulnerable to harmful exposures through their skin because they have more skin surface area relative to their body size, better blood flow, and higher skin hydration than adults. A recent study found that using skincare lotions and oils significantly increased toxic phthalates in children’s urine.

Researchers surveyed parents of children aged 4 to 8 about their children’s use of skincare products and then tested the children’s urine for phthalates.

They discovered that children who used lotions had 1.17 times more mono-benzyl phthalate in their urine, and those exposed to oils had 2.86 times more monoethyl phthalate, 1.43 times more monobutyl phthalate, and 1.40 times more low-molecular-weight phthalates. Surprisingly, children who used products labeled “phthalate-free” didn’t have lower phthalate levels. The researchers speculated that phthalates used in packaging materials (such as bottles or tubes) migrated into the products.

These findings suggest that everyday skincare products, such as lotions or oils, expose children to high phthalate levels. Phthalates are known endocrine disruptors—compounds that can mimic or impair the activity of the body’s natural hormones and may harm children’s development and physiology.

Many skincare products also contain microplastics, which carry considerable health risks. Learn more about microplastics in our overview article.

Local water sources likely contribute a shocking 2,400 microplastic particles to a typical serving of soda. www.sciencedirect.com

Diet Pollution

If drinking a nice, cold soda sounds appealing, you’re not alone. Roughly half of all adults and nearly two-thirds of kids in the US consume at least one soft drink daily—mostly sodas. These drinks typically contain considerable amounts of sugar, raising concerns about their effects on dental and metabolic health. However, a recent study has uncovered a more alarming issue: Microplastic contamination is pervasive in these popular beverages.

Researchers analyzed the microplastic content in a popular soda brand purchased in various US locations: Atlanta, Los Angeles, Chicago, and Washington, DC. The sodas were in aluminum, glass, or plastic containers.

They found that the average concentration of microplastic particles in 100 milliliters of soda was 166, with some samples reaching a staggering 482 particles—meaning that a typical 16.9-ounce (~500-milliliter) bottle of soda could contain more than 2,400 microplastic particles. Interestingly, the sodas in glass containers had the highest concentrations of particles. The study investigators speculated that the primary contributors to the sodas' microplastic contamination were local water sources (near the packaging plants).

These findings suggest that microplastic contamination in sodas is ubiquitous and adds to the growing body of evidence about microplastics in food and beverages. Learn more about microplastics in our overview article.

Microplastics absorbed in the gut may promote cancer cell migration and metastasis. www.sciencedirect.com

Cancer Gut Pollution

Plastic pollution is a growing environmental concern, with tiny plastic particles infiltrating various ecosystems, including the human body. The gut is crucial in this process, serving as the main gateway for microplastics and nanoplastics to enter the body. A recent study found that human colorectal cancer cells can absorb microplastic particles, raising concerns about their potential effects on health.

Researchers exposed four human colorectal cancer cell lines to polystyrene micro- and nanoplastics of various sizes (0.25, 1, and 10 micrometers) and concentrations. They tracked the particles' uptake into cells and monitored their behavior during cell division.

They found that all the cancer cells absorbed micro- and nanoplastics, with the highest uptake observed in HCT116 cells—a type of cells commonly used to study various aspects of tumor biology. Notably, the cells didn’t eliminate the absorbed particles. Instead, they passed them on during cell division, sharing them between the original and new cells. Even short-term exposure to the smallest particles (0.25 micrometers) increased the cells' movement, which could facilitate metastasis.

These findings suggest that micro- and nanoplastics accumulate in cells and pass into progeny cells during cell division. Once inside the cells, they promote cell migration, potentially enhancing the spread of cancer. Some harmful effects of microplastics may be due to compounds commonly used in plastic manufacturing, such as bisphenol A, phthalates, and heavy metals. Learn more about microplastics in our overview article.

Early exposure to a common pollutant changes the gut microbiome, potentially influencing metabolic health. ehp.niehs.nih.gov

Microbiome Metabolism Hormones Inflammation Pollution

Persistent organic pollutants are pervasive environmental toxicants that threaten human health. These compounds break down slowly and are often called “forever chemicals.” Surprisingly, the concern isn’t just that these chemicals affect health but rather the mechanisms by which they do so. A recent study in mice found that exposure to persistent organic pollutants altered the animals' gut microbiome composition, skewing it toward a less beneficial profile.

Researchers exposed young mice to the persistent organic pollutant tetrachlorodibenzofuran (TCDF), a widely distributed byproduct of various chemical processes. They analyzed the animals' gut microbial composition and assessed the physiological and metabolic effects of the exposure.

They found that mice exposed to TCDF had lower quantities of short-chain fatty acids, indole-3-lactic acid (an anti-inflammatory compound), and hunger-modulating hormones. Exposed mice also had fewer Akkermansia muciniphila, a type of bacteria that modulates metabolism.

These findings suggest that early life exposure to persistent organic pollutants alters the gut microbiome in mice, adversely affecting metabolism. Learn about the importance of early life establishment of the gut microbiome in this episode featuring Dr. Eran Elinav.

Melamine cleaning sponges, known as "magic erasers," may contribute up to 4.9 trillion microplastic particles to aquatic environments globally, due to breakdown during use. www.eurekalert.org

Pollution Environment

Melamine cleaning sponges are composed of hard, plastic strands assembled into a soft, lightweight foam. Commonly known as “magic erasers,” they are immensely popular due to their highly abrasive qualities. A recent study found that the global microplastic burden from melamine cleaning sponges may exceed 4.9 trillion particles, based on current sales.

Researchers assessed microplastic release from melamine cleaning sponges under different scrubbing conditions, focusing on the shape, makeup, and number of fibers created. Then they quantified annual accumulation based on typical melamine sponge sales from two popular online retailers.

They found that melamine sponges released straight and branched microplastic fibers made of poly(melamine-formaldehyde) polymer, ranging from 10 to 405 micrometers long. These fibers formed as the sponge’s structure broke down due to friction; consequently, the rougher the surface and denser the sponge, the more fibers produced. They estimated that sponge wear could release up to 6.5 million fibers per gram of sponge, potentially contributing up to 4.9 trillion fibers to aquatic environments globally.

These findings suggest that melamine cleaning sponges are major contributors to the global microplastic burden. Human exposure to microplastics occurs through ingestion, inhalation, and skin contact. Evidence indicates that these particles accumulate in various body fluids and tissues and may increase the risk for metabolic dysfunction, neurotoxicity, and some cancers.

Read study abstract.

Coming soon: A comprehensive overview article about microplastics and their putative effects on human health.

Shorter-chain PFAS alternatives, found in common household products, readily penetrate human skin, potentially increasing the health risks associated with these "forever chemicals." www.sciencedaily.com

Cancer Immune System Pollution Environment Skin

Perfluoroalkyl substances, or PFAS, are synthetic compounds found in food packaging, household products, and plastic bottles. These “forever chemicals” persist in the body for indefinite periods, posing significant health risks such as cancer, liver damage, and immune system dysfunction. To address these concerns, chemical companies have introduced shorter-chain PFAS alternatives, which break down more quickly in the environment. However, a recent study found that these alternatives readily penetrate the skin, potentially increasing the health risks associated with PFAS exposure.

Researchers designed a three-dimensional model that mimicked the qualities of human skin. They applied various PFAS to the model skin, including perfluoroalkyl carboxylic acids (used on/in non-stick cookware, water and stain repellents, and food packaging) and perfluoroalkane sulfonic acids (used on/in carpets, clothing, paper products, and cleaning agents) and assessed whether the compounds were absorbed (consequently taken up into the bloodstream), unabsorbed, or retained within skin tissue.

The researchers found that the skin absorbed as much as 58.9% of short-chain PFAS, and the absorption rate decreased as the carbon chain length increased. Interestingly, they found that large quantities of longer-chain PFAS (as much as 68.3%) were retained in the skin instead of being absorbed.

These findings suggest that PFAS, especially shorter-chain forms, readily penetrate human skin and can gain access to the bloodstream. They also underscore the potential health risks of PFAS exposure and the need for further research and regulation.

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People with inflammatory bowel disease have 49 percent more microplastics in their feces than healthy people, suggesting a potential link between microplastics and chronic gut inflammation. pubs.acs.org

Gut Inflammation Pollution Intestinal Permeability

Inflammatory bowel disease (IBD) is an umbrella term for chronic inflammatory conditions that affect the gut, primarily Crohn’s disease and ulcerative colitis. A growing body of evidence suggests that microplastics – tiny plastic particles ranging between 5 millimeters and 100 nanometers – are pro-inflammatory, potentially contributing to chronic disease. A recent study found that people with inflammatory bowel disease had roughly 49 percent more microplastics in their feces than healthy people.

Researchers measured microplastic concentrations in the feces of 102 participants. Half of the participants had IBD, and the other half were healthy. Participants completed questionnaires about their plastic usage and exposure.

The researchers found that the fecal concentration of microplastic particles in the feces of participants with inflammatory bowel diseases averaged 41.8 particles per gram of dry matter. In comparison, healthy participants' concentrations averaged 28.0 particles per gram. The various particles were in sheets, fibers, fragments, and pellets; most were smaller than 300 micrometers. Participants with higher fecal concentrations tended to have more severe IBD. The primary sources of microplastic exposure were plastic packaging (for food and water) and dust.

These findings suggest that microplastic exposure is linked to the disease process of IBD or that IBD might exacerbate microplastic retention in the body. They also add to the growing evidence suggesting that microplastics influence human health. Scientists have found microplastics throughout the human body, including the sputum, lungs, heart, liver, blood, endometrium, testis, amniotic fluid, and placenta00153-1/fulltext).

Microplastics were identified in 80 percent of surgically removed blood clots, potentially elevating the risk and severity of heart attacks, strokes, and respiratory issues. www.thelancet.com

Pollution Environment Cardiovascular

Blood clots that form in the heart, arteries, and veins – called thrombi – are a major risk factor for heart attack, stroke, and respiratory problems. Evidence suggests that environmental factors contribute to thrombi formation. A recent study identified microplastics in 80 percent of surgically removed thrombi.

Researchers surgically removed thrombi from patients scheduled for arterial or venous thrombectomy in the brain, heart, or legs using plastic-free surgical implements and storage techniques. Using mass spectrometry, they assessed the thrombi for microplastic particle content and determined the particles' sizes, shapes, and numbers.

They found that 80 percent of the thrombi contained microplastics, including polyamide 66, polyvinyl chloride, and polyethylene. Higher concentrations of microplastics were associated with greater disease severity.

This study was small, but its findings suggest microplastics are present in human thrombi and further increase disease risk. Microplastics are pervasive environmental contaminants present in land, water, and air. They have also been detected throughout the human body, including the sputum, lungs, heart, liver, blood, endometrium, testis, amniotic fluid, and placenta. Recent research found that microplastics in human arterial plaques increase the risk for cardiovascular disease-related events nearly fivefold.

High levels of "forever chemicals" linked with cancer and reproductive problems found in seafood. www.sciencedaily.com

Cancer Pollution Environment

Polyfluoroalkyl substances, or PFAS, are synthetic compounds used in food packaging, household products, and drinking water. PFAS aren’t excreted in bodily fluids like sweat or urine; instead, they persist in the body indefinitely and are often referred to as “forever chemicals.” A recent study found that seafood – including fish and shellfish – contains high PFAS levels.

Researchers asked more than 1,800 people living in the northeastern U.S. about the amount and types of seafood they ate. Then, they measured PFAS levels in fish, lobster, shrimp, and scallops purchased from a market in that area.

They found that the participants were regular seafood consumers, with adults consuming approximately 34 grams daily and children consuming 5 grams – slightly higher than national averages. They also found that the fish contained less than 1 nanogram per gram (ng/g) of PFAS; the shrimp contained 1.74 ng/g, and the lobster contained 3.30 ng/g. These levels may pose health concerns among high seafood consumers.

These findings suggest that seafood is an abundant source of PFAS. Future research may illuminate the benefits and risks of consuming seafood. Exposure to PFAS has been linked to various health issues, including increased cholesterol levels, changes in liver function, and impaired immune function. Some studies suggest a potential association between PFAS exposure and increased risks of certain cancers and reproductive problems

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Microplastic accumulation in arterial plaques increases the risk for cardiovascular disease-related events nearly fivefold. www.nbcnews.com

Heart Disease Inflammation Bisphenol A Pollution Oxidative Stress Cardiovascular

Tiny plastic particles, often called microplastics – ranging between 5 millimeters and 100 nanometers – are ubiquitous environmental pollutants. Scientists have identified microplastics in food (especially seafood), soil, drinking water, fresh- and saltwater bodies, and air. A recent study found that microplastics accumulate in human arterial plaques, increasing the risk for cardiovascular disease-related events, such as heart attack or stroke, nearly fivefold.

The study involved 257 patients undergoing carotid endarterectomy, a procedure in which a surgeon removes plaques from the heart’s arteries. Researchers analyzed the plaque for the presence of microplastics, measured the patients' inflammatory biomarkers, and tracked their health for about three years.

They found that more than half of the patients (58.4 percent) had microplastics in their arterial plaques, appearing as jagged-edged foreign particles. Those with microplastics in their plaques were 4.53 times more likely to experience a cardiovascular disease-related event during the three-year follow-up than those without microplastics. They were also more likely to be male, younger, and have diabetes, cardiovascular disease, abnormal blood lipids, and higher inflammatory markers.

These findings suggest that microplastics, a ubiquitous environmental pollutant, accumulate in arterial plaques, markedly increasing the risk of cardiovascular disease-related events. Evidence indicates that microplastic exposure is associated with many other adverse health outcomes. For example, a comprehensive review of the effects of microplastics revealed that microplastics induce oxidative stress and increase the risk for metabolic dysfunction, neurotoxicity, and some cancers. Some of these effects may be due to compounds commonly associated with plastic manufacturing, such as bisphenol A, or BPA, phthalates, and heavy metals that are present in and on microplastics.

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Commonly used haircare products emit toxic, airborne compounds during a typical home haircare session. engineering.purdue.edu

Pollution Environment

Many hair care products contain siloxanes – a broad class of silicone-based compounds – that can become airborne during hair drying and styling. Evidence suggests siloxanes persist in the environment and cause liver or lung damage in rodents. A recent study found that a person can inhale up to 17 milligrams of siloxanes in a single home haircare session.

Researchers conducted multiple experiments that replicated typical home haircare sessions using hair dryers, styling equipment, and products. Then, they measured the amount of chemicals emitted during the sessions using mass spectrometry.

They found that the number of airborne chemicals emitted during haircare sessions, including monoterpenes, monoterpenoids, and propylene glycol, increased considerably indoors, especially when the various haircare products were heated. The most abundant chemical was a siloxane compound called D5, with participants inhaling up to 17 milligrams of siloxane in a single session.

Using an exhaust fan reduced the amount of inhalable D5 by roughly half; however, the quantities of the exhausted compound increased outdoors. The researchers estimated that the emission of D5 from indoor to outdoor environments in the U.S. could be as high as six metric tons yearly.

These findings suggest that people who use widely available haircare products in indoor environments are exposed to large quantities of inhalable, harmful compounds. These compounds can then be transmitted to the outdoor environment, where they persist, potentially posing considerable health threats.

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High particulate matter exposure increases the risk of Parkinson's disease by nearly 20 percent. www.neurology.org

Parkinson's Pollution Environment Neurodegeneration

People who live in large cities or near industrial areas are often exposed to high levels of particulate matter – a mixture of solid particles and liquid droplets in air pollution that forms fine inhalable particles with diameters typically 2.5 micrograms (PM2.5) or less. A recent study found that high exposure to PM2.5 increases the risk of developing Parkinson’s disease by nearly 20 percent.

Researchers conducted a population-based study of more than 21 million older adults living in the US. They assessed their exposure to particulate matter based on their geographical location and ascertained whether they had Parkinson’s disease based on Medicare records.

They found that people exposed to the median PM2.5 level were 56 percent more likely to develop Parkinson’s than those with the lowest PM2.5 exposures. For every additional microgram per cubic meter of PM2.5 exposure, risk increased by 4.2 percent. In the Mississippi-Ohio River Valley, where particulate matter levels are high, the risk of developing Parkinson’s disease was 19 percent greater than in the rest of the country.

These findings suggest that exposure to particulate matter markedly increases a person’s risk of developing Parkinson’s disease, aligning with other evidence pointing to the disease’s environmental origins. Parkinson’s disease is a neurodegenerative disorder that affects the central nervous system. Caused by the destruction of nerve cells in the part of the brain called the substantia nigra, it typically manifests later in life and is characterized by tremors and a shuffling gait. Learn more about Parkinson’s disease and therapies in this episode featuring Dr. Giselle Petzinger.

Herbicide exposure linked to impaired neurobehavioral performance in teens. neurosciencenews.com

Parkinson's Development Pollution

Exposure to environmental toxins can harm brain health, especially in teens and children, who are fundamentally more vulnerable than adults to toxic exposures. Herbicides to control weeds and insect repellents to control vector-borne diseases are prevalent worldwide, but scientists don’t fully understand their effects on brain health. A new study shows that exposure to common herbicides impairs teen neurobehavioral performance.

Researchers measured urinary concentrations of common herbicides (glyphosate and 2,4-D) and an insect repellent (N,N-diethyl-meta-toluamide, commonly known as DEET) in 519 teens living in agricultural communities in Ecuador. They tested the teens' neurobehavioral performance in five areas: attention/inhibitory control, memory/learning, language, visuospatial processing, and social perception.

They detected glyphosate in the urine of 98.3 percent of the teens and 2,4-D in 66.2 percent. Higher glyphosate concentrations correlated with lower scores in social perception; higher 2,4-D concentrations correlated with lower scores in attention/inhibitory control, memory/learning, and language. DEET exposure did not influence neurobehavioral performance.

Glyphosate is a broad-spectrum herbicide widely used in agriculture and forestry to control unwanted vegetation. It is known for effectively eliminating weeds and has been a key component of many commercial herbicide products, including Roundup. However, the use of glyphosate has also been a subject of controversy due to concerns about its potential harm to human health and the environment.

These findings suggest that herbicide exposure negatively influences neurobehavioral performance in teens. Listen to Dr. Rhonda Patrick discuss herbicides, pesticides, and disease risk in this Q&A.

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Agricultural PM2.5 pollution significantly worse for dementia risk: 13 percent increase compared to 5 percent from wildfires. www.sciencedaily.com

Aging Dementia Pollution

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. It forms fine inhalable particles with diameters typically 2.5 micrograms (PM2.5) or less. Exposure to particulate matter promotes oxidative stress and increases the risk of developing many chronic diseases, including cardiovascular disease, cancer, hypertension, and diabetes. A recent study found that particulate matter in air pollution from agriculture increases the risk of dementia in older adults.

The study involved more than 27,000 adults enrolled in the Environmental Predictors of Cognitive Health and Aging study. Participants were over the age of 50 and dementia-free at the time of enrollment. Using spatiotemporal and chemical transport models, researchers assessed the participants' exposure to PM2.5 from nine emission sources over a 10-year period.

They found that exposure to higher levels of PM2.5 increased the risk of dementia by 8 percent. When they examined specific PM2.5 sources, they discovered that agriculture PM2.5 increased dementia risk by 13 percent, while wildfire PM2.5 increased risk by 5 percent.

These findings suggest that reducing PM2.5 pollution, particularly from agricultural and wildfire sources, could benefit cognitive health in older adults. However, further research is necessary to validate these findings and explore potential intervention strategies.

Evidence suggests that sulforaphane, a bioactive compound derived from broccoli, counters some of the harmful effects of particulate matter. Learn more about sulforaphane in our comprehensive overview article.

Read study abstract.

Air pollution exposure impairs strategic decision-making. www.sciencedaily.com

Brain Pollution

Exposure to air pollution increases a person’s tendency to make mistakes, a new study shows. Chess players who were exposed to fine particulate matter in air pollution made more frequent – and more serious – mistakes during play than when not exposed.

The study involved 121 elite chess players. Researchers measured the players' exposure to air pollutants during tournament play over a period of about three years. Then, using artificial intelligence, they assessed the players' performance during each of the tournaments.

They found that a modest increase in particulate matter of just 10 micrograms per cubic meter increased a player’s probability of making a mistake by more than 26 percent. In general, this modest increase raised mistake severity by nearly 11 percent. However, later in the matches, when decision-making time became limited, the increase in the particulate matter raised mistake severity by more than 20 percent.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. It is present in fine inhalable particles, with diameters that are generally 2.5 micrograms or less. Evidence suggests that exposure to particulate matter in air pollution promotes oxidative stress, increases the risk of developing many chronic diseases, and accelerates aging.

These findings suggest that exposure to particulate matter in air pollution impairs decision-making and increases mistakes. Such findings may have relevance for people who work in professions that require strategic decision-making while experiencing exposure to particulate matter, such as firefighters or air traffic controllers, or for those who live or work downwind from pollution sources.

People who live in highly urban environments near busy roads may wish to consider using a high-quality air purifier such as a HEPA filter to help reduce their exposure to particulate matter.

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Higher fetal exposure to air pollution during the second and third trimester of pregnancy score lower in cognition, motor coordination, and language www.colorado.edu

Brain Pregnancy Development Pollution

Exposure to air pollution during mid-to-late pregnancy interferes with fetal neurodevelopment.

Exposure to air pollution during mid-to-late pregnancy interferes with fetal neurodevelopment, a new study shows. Children whose mothers were exposed to high levels of air pollution scored roughly three points lower on cognitive tests than children exposed to lower levels.

The study involved 161 mother-child pairs living in Southern California, an area known for its high air pollution levels. The researchers gauged the mothers' exposure to particulate matter (a mixture of solid particles and liquid droplets that may have neurotoxic properties) during their pregnancies. When the children reached the age of two years, they underwent tests to assess their neurodevelopment.

The researchers found that children who were exposed to particulate matter in air pollution during pregnancy – especially during the second and third trimesters – had lower composite cognitive scores than children exposed to lower levels. They also performed worse on measures of fine and gross motor skills, language, and expressive communication.

These findings suggest that fetal exposure to particulate matter in air pollution during the second and third trimesters of pregnancy impairs cognitive performance later in life. These trimesters correspond with periods during which critical neurodevelopmental processes occur, such as myelination, neuronal migration, synaptogenesis, and neurogenesis.

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Just two hours of air pollution exposure interferes with regular brain activity. www.sciencedaily.com

Depression Pollution Blood-Brain Barrier

Even short-term exposure to air pollution affects brain function, a new study shows. People exposed to diesel exhaust for just two hours had reduced connectivity in areas of the brain associated with attention and focus.

Researchers exposed 25 healthy adults to diesel exhaust and filtered air for two hours, with a two-week break between each exposure. Before and after the exposures, the researchers measured activity in a region of the participants' brains called the default mode network.

They found that compared to pre-exposure, participants had reduced connectivity throughout the default mode network of their brains after brief exposure to diesel exhaust. There were no changes in connectivity following exposure to filtered air.

The default mode network is a collection of interconnected neural structures involved in attention and focus. Disturbances in default mode network connectivity are associated with poor working memory, reduced performance, and work-related productivity losses.

Sulforaphane, a bioactive compound derived from broccoli – and particularly abundant in broccoli sprouts – promotes urinary excretion of some components of air pollution. Learn more in the clip featuring Dr. Jed Fahey.

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Air pollution may increase stroke risk for intracerebral hemorrhage by 54%. (2003) www.sciencedaily.com

Pollution Aneurysm

Exposure to air pollution increases the risk of stroke by more than half.

Air pollution contains many toxic substances, including chemicals, gases, and particulate matter – a mixture of solid particles and liquid droplets that exert neuroinflammatory effects. Exposure to air pollution promotes oxidative stress and increases the risk of developing many chronic diseases, such as cardiovascular disease, cancer, hypertension, and diabetes, markedly shortening people’s lives. Findings from a 2003 study suggest that exposure to air pollution is associated with an increased risk of stroke.

A stroke is a neurological disorder characterized by the interruption of blood flow to the brain. Strokes are typically classified as either ischemic or hemorrhagic. Ischemic strokes, which account for approximately 87 percent of all strokes, are characterized by the blockage of an artery. Hemorrhagic strokes, which account for 13 percent of strokes, are characterized by bleeding from a blood vessel that supplies the brain.

The researchers reviewed admission data from hospitals in and around Kaohsiung, Taiwan, an industrial area known for its high levels of air pollution. They obtained air quality assessments of the same area via government monitoring stations that provided measurements of gases (sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone) and particulate matter with diameters of 10 micrograms (PM10) or less. Because weather influences air quality, they also collected humidity and temperature readings from the government weather agency.

They found that exposure to higher levels of nitrogen dioxide and PM10 was associated with increased risk of stroke, especially on warm days (68°F or warmer). The risk of ischemic stroke increased by 55 percent for greater nitrogen dioxide exposure and by 46 percent for greater PM10 exposure. The risk for hemorrhagic stroke increased by 54 percent with greater exposure to either nitrogen dioxide or PM10.

These findings suggest that exposure to common air pollutants, especially during warmer weather, increases the risk of stroke. The investigators posited that this increased risk is due to the inflammatory effects of particulate matter and the increase in plasma viscosity and serum cholesterol levels that occur with exposure to high temperatures and humidity.

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Using a HEPA filter during pregnancy increased child full-scale IQ by 2.8 points. medicalxpress.com

Brain Pregnancy Development Pollution

Background: Developmental exposure to air pollution is associated with diminished cognitive abilities in observational studies, but no randomized controlled trial has examined the effect of reducing air pollution on cognition in children.

Objectives: We sought to quantify the impact of reducing exposure to particulate matter (PM) during pregnancy on children’s cognitive performance at 4 y of age.

Methods: In this single-blind, parallel-group, randomized controlled trial in Ulaanbaatar, Mongolia, we randomly assigned 540 nonsmoking pregnant women (268 intervention and 272 control) to receive 1–2 portable high-efficiency particulate air (HEPA) filter air cleaners or no air cleaners. The air cleaners were used from a median of 11 wk gestation until the end of pregnancy. The primary outcome was full-scale intelligence quotient (FSIQ) assessed using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) when children were a median of 48 months old. We imputed missing outcome data using multiple imputation with chained equations, and our primary analysis was by intention to treat.

Results: After excluding known miscarriages, stillbirths, neonatal deaths, and medical conditions that impeded cognitive testing and imputation, 475 (233 control and 242 intervention) children were included in our analyses. In an unadjusted analysis, the mean FSIQ of children who were randomly assigned to the intervention group was 2.5 points [95% confidence interval (CI): −0.4, 5.4 points] higher than that of children in the control group. After adjustment to account for an imbalance in preterm birth between groups, the effect estimate increased to 2.8 points (95% CI: −0.1, 5.7).

Conclusions: Reducing PM air pollution during pregnancy may improve cognitive performance in childhood.

Link to full publication.

Air pollution may attenuate the beneficial association vigorous physical activity with low white-matter hyperintensity volume n.neurology.org

Exercise Brain Aging Pollution Aerobic Neurodegeneration Small Vessel Disease

Air pollution negates some of the beneficial effects of vigorous-intensity exercise.

Components present in air pollution – a mixture of toxic chemicals, gases, and particulate matter – can cross biological barriers, including the blood-brain barrier. Exposure to air pollutants is associated with poor health outcomes and an increased risk for both acute and chronic diseases. A recent study suggests that air pollution negates some, but not all, of the beneficial effects of vigorous-intensity aerobic exercise.

Robust evidence demonstrates that vigorous-intensity aerobic exercise (defined as activity that achieves a heart rate that is 70 to 80 percent of one’s maximum) benefits brain health. For example, vigorous-intensity aerobic exercise appears to activate the endocannabinoid system to promote motor sequence memory and learning. Other evidence suggests it improves mood.

The study involved 8,600 adult participants enrolled in the UK Biobank study. Participants wore wrist accelerometers to track their physical activity. They also underwent magnetic resonance imaging (MRI) to assess their structural brain volumes and identify the presence of white matter hyperintensities – areas of the brain that show up as distinct white areas on MRIs and indicate cerebral small blood vessel disease. The investigators estimated the participants' exposure to air pollution based on where the participants lived.

The investigators found that the more physically active participants were, the less their brains showed evidence of shrinkage, and the fewer white matter hyperintensities they exhibited – an effect roughly equivalent to being three years younger. Participants who were exposed to more air pollution exhibited greater brain shrinkage than those with less exposure – about the amount observed in one year of normal aging. However, participants who exercised the most and had the most exposure to air pollution demonstrated no evidence of more brain shrinkage, but they exhibited more white matter hyperintensities, especially if they engaged in vigorous-intensity aerobic exercise.

These findings support earlier studies that demonstrate the beneficial health effects of vigorous-intensity exercise on the brain but suggest that exercising in areas where air pollution is high negates some of these benefits. The authors recommended that because most air pollution comes from vehicle exhaust, people should exercise in areas far from heavily trafficked roads.

PCB exposure linked to increased visceral fat: "persistent compound PCB189 was related to a high proportion of fat in the abdomen" www.sciencedaily.com

Obesity Pollution Metabolic Syndrome Visceral Fat

Exposure to PCBs may increase visceral fat.

Persistent organic pollutants are ubiquitous environmental toxicants that pose considerable threats to human health. These compounds typically degrade slowly and are often referred to as “forever compounds.” A 2012 study found that exposure to the organic pollutants polychlorinated biphenyls (PCBs) was associated with having increased visceral fat.

PCBs were historically used in industrial and chemical applications, such as coolants, transformer insulators, capacitors, motors, paints, and electrical wire coatings. Although PCBs have been banned in the United States, the compounds are widespread in the environment. Exposure to PCBs is associated with an increased risk of adverse health effects, including many chronic disorders, such as cardiovascular disease, diabetes, hypertension, melanoma, and non-Hodgkin’s lymphoma. PCB exposure may also be linked to neurodegenerative disease PCBs bioaccumulate in human muscle and adipose tissue, brain, liver, and lungs and have long elimination half-lives, ranging from 10 to 15 years.

The cross-sectional study involved more than 1,000 adults (70 years and older) living in Sweden. Participants provided information about their medical histories, education level, exercise habits, smoking habits, and medication use. A subset of 287 participants underwent magnetic resonance imaging to assess body fat location and quantity. Investigators collected blood samples from the participants to detect the presence of persistent organic pollutants.

They found that higher blood concentrations of the organic pollutant PCB189, a highly chlorinated PCB, were associated with having greater quantities of visceral fat, suggesting that environmental exposures influence fat deposition in humans. Interestingly, PCB189 exposure and increased visceral fat are associated with type 2 diabetes, potentially providing a mechanistic link between body fat and diabetes risk.

Although exposure to persistent organic pollutants is likely unavoidable, some PCBs are excreted in sweat. Sauna use, which induces copious sweating, may promote PCB excretion. Learn more about the beneficial health effects of sauna use in our overview article.

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Living in Areas With More Greenery May Boost Cognitive Function neurosciencenews.com

Brain Pollution

Residential greenspace exposure improves cognitive function.

Spending time in nature is associated with a variety of beneficial effects on mental and physical health. For example, recent research demonstrated that spending time in the natural environment reduces ruminative thinking. Other research indicates that walking in forested areas improves immune function, likely due to beneficial bioactive compounds produced by trees and inhaled by walkers. Findings from a new study suggest that residential greenspace exposure improves cognitive function in middle-aged women.

The investigation included more than 13,000 women enrolled in the Nurses' Health Study II, an ongoing study of health outcomes of female nurses living in the United States. The participants completed an online battery of cognitive tests that gauged psychomotor speed, attention, learning, and working memory. The investigators calculated the participants' exposure to greenspace based on satellite imagery of their residential address and evaluated the effects of possible mediators of cognitive function, such as air pollution exposure, depression, and physical activity.

They found that even after considering the participants' ages at assessment, race, and socioeconomic status, women who had greater greenspace exposure scored higher on aspects of psychomotor speed and attention than women with less exposure. The difference in scores was roughly equivalent to one year of chronological aging. Greenspace exposure did not appear to affect learning or working memory. They also found that exposure to pollution was not a mitigating factor, but depression was, aligning with previous research.

These findings suggest that residential greenspace exposure benefits cognitive performance in middle-aged women. They also underscore the importance of public health efforts to promote the incorporation of natural areas into urban planning.

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APOE4 carriers had a 4.92 higher odds of committing suicide in a high air pollution environment (mexico city) www.sciencedaily.com

Brain Alzheimer's Depression Genetics Pollution

Air pollution exposure promotes Alzheimer’s disease-related hallmarks in the brains of children.

Components present in air pollution – a mixture of chemicals, gases, and particulate matter – can cross biological barriers, including the blood-brain barrier. Evidence suggests that children exposed to air pollution exhibit altered brain structure and metabolic function and demonstrate impaired cognitive performance. A 2018 study identified pathological hallmarks associated with Alzheimer’s disease in the brains of children and young adults living in Mexico City, an area known for its high levels of air pollution.

The primary pathological hallmarks associated with Alzheimer’s disease are amyloid-beta plaques and tau neurofibrillary tangles. Amyloid-beta is a toxic 42-amino acid peptide that clumps together, forming plaques in the brain. Tau is a protein that, when modified via the chemical process of phosphorylation, can form aggregates called neurofibrillary tangles in the brain. Scientists classify the severity of neurofibrillary tangle formation according to the Braak staging system, which ranks severity on a scale of I to VI, with VI being the most severe.

The investigators examined autopsy-derived brain tissues from 203 subjects living in Mexico City, ranging in age from 11 months to 40 years, to identify the presence of amyloid-beta plaques and tau neurofibrillary tangles. They calculated the subjects' cumulative burden of particulate matter exposure based on their place of residence and noted the subjects' cause of death. They also conducted genotyping to determine whether the subjects were carriers of APOE4, a genetic variant that increases a person’s risk of developing Alzheimer’s disease.

They found that 99.5 percent of the subjects' brains exhibited abnormally high levels of amyloid-beta and hyperphosphorylated tau, even as early as 11 months of age. Approximately one-fourth of subjects between the ages of 30 and 40 years exhibited stage III or IV neurofibrillary tangles. Subjects who carried the APOE4 variant were at least 23 times more likely to exhibit stage IV tangles. Interestingly, APOE4 carriers were nearly five times more likely to commit suicide than non-carriers.

These findings suggest that exposure to air pollution in early life increases a person’s risk for developing Alzheimer’s disease. People who carry the high-risk genetic variant APOE4 are at substantially greater risk and may, additionally, be vulnerable to greater suicide risk. Omega-3 fatty acids help maintain blood-brain barrier integrity and may reduce the risk of Alzheimer’s disease in APOE4 carriers. Learn more in this open-access peer-reviewed article by Dr. Rhonda Patrick.

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Air pollution may promote the production of autoantibodies against tight-junctions and neural proteins: neuroinflammation in children in Mexico City www.sciencedaily.com

Brain Alzheimer's Inflammation Pollution Autoimmunity Blood-Brain Barrier

Exposure to air pollution promotes the production of autoantibodies against tight-junctions of the blood-brain barrier.

Separately, evidence has also shown that even very young children show evidence of amyloid-beta build up under these conditions.

From the article:

The study found when air particulate matter and their components such as metals are inhaled or swallowed, they pass through damaged barriers, including respiratory, gastrointestinal and the blood-brain barriers and can result in long-lasting harmful effects.

The results found that the children living in Mexico City had significantly higher serum and cerebrospinal fluid levels of autoantibodies against key tight-junction and neural proteins, as well as combustion-related metals.

“We asked why a clinically healthy kid is making autoantibodies against their own brain components,” Calderón-Garcidueñas said. “That is indicative of damage to barriers that keep antigens and neurotoxins away from the brain. Brain autoantibodies are one of the features in the brains of people who have neuroinflammatory diseases like multiple sclerosis.”

Microplastics found deep in lungs of living people for first time www.theguardian.com

Pollution

Microplastics found in human lungs.

Microplastics are small pieces of plastic or other polymer-based materials, typically less than five millimeters (about one-quarter inch) in size. They are ubiquitous environmental pollutants, having been identified in food (especially seafood), soil, drinking water, fresh- and saltwater bodies, and air. A recent study has identified microplastics in human lungs.

Exposure to microplastics has been associated with a wide range of negative health outcomes in humans. For example, a comprehensive review of the effects of microplastics revealed that the pollutants induce oxidative stress and increase the risk for metabolic dysfunction, neurotoxicity, and some cancers. Some of these effects may be due to compounds commonly associated with plastic manufacturing, such as bisphenol A, or BPA, phthalates, and heavy metals, that are present in and on microplastics.

The investigators collected lung tissue samples from the upper, middle, or lower lobe of 13 patients (average age, 63 years) undergoing scheduled lung surgery. They soaked the tissue samples in hydrogen peroxide to break down the tissue while maintaining the integrity of non-human materials. Then they characterized the materials using spectroscopy, a research tool that uses light scatter to measure concentration.

They identified a total of 39 microplastic fibers, fragments, or films in 11 of the 13 samples, an average of three per sample, ranging up to eight per sample and equating to approximately 0.69 microplastics per gram of tissue. They identified 12 different polymer types, the most abundant of which were polypropylene (23 percent) and polyethylene terephthalate (18 percent), commonly known as PET. Polypropylene is used in a wide range of manufacturing applications, including food containers and plastic pipes. PET is commonly used in water and soft drink bottles.

These findings demonstrate that inhaled microplastics may be present in human lungs. They also underscore the need for further investigation into the health effects of microplastic exposure.

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Particulate matter in wildfires harms the brain. www.eurekalert.org

Pollution Neurodegeneration

Global climate change is driving an increase in wildfire activity characterized by larger fires and longer fire seasons. Wildfire smoke, which can spread over immense geographical areas, often contains a variety of pollutants and exerts a wide range of adverse effects on human health. Evidence from a new rodent study suggests that particulate matter in wildfires drives neuroinflammation, increasing the risk for neurodegenerative diseases.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. It is present in fine inhalable particles, with diameters that are generally 2.5 micrograms (PM2.5) or less. Ultrafine particles less than 1 microgram in diameter, referred to as nanoparticles, are often enriched in highly reactive metals such as iron, aluminum, titanium, and others. Exposure to particulate matter in air pollution promotes oxidative stress, increases the risk of developing many chronic diseases, and accelerates aging.

The investigators studied the effects of wildfire smoke on mice that were housed in a mobile lab located roughly 186 miles (300 kilometers) away from naturally occurring wildfires in the western United States. They exposed the mice to the smoke for four hours every day for 20 days and assessed the animals' immune and inflammatory responses.

They found that the animals were exposed to high levels of PM2.5. This exposure switched on the activity of brain microglia (immune cells); promoted the infiltration of pro-inflammatory immune cells and molecules into the brain tissues; and increased accumulation of amyloid-beta 42, a toxic protein associated with Alzheimer’s disease and neurodegeneration. Particulate matter exposure also decreased the production of compounds that protect the brain against aging, such as nicotinamide adenine dinucleotide (commonly known as NAD+) and taurine.

These findings suggest that exposure to PM2.5 in wildfire smoke elicits harmful effects on the brain via activation of immune and inflammatory responses. The investigators noted that the mobile lab used in this study was located a considerable distance from the smoke sources, likely diluting the animals' exposure and reflecting PM2.5 exposures far lower than those experienced by humans living closer to the fires.

Robust evidence demonstrates that HEPA filter air purifiers reduce indoor PM2.5 concentrations and improve health outcomes, and many government agencies and public health authorities recommend the use of indoor HEPA filters to reduce wildfire smoke exposure and its negative health effects. In addition, well-fitting N95 masks and equivalent respirators can reduce PM2.5 exposure. Interestingly, dietary consumption of omega-3 fatty acids may help protect the brain from damage associated with PM2.5 exposure. Learn more about the health effects of omega-3 fatty acids in this episode featuring Dr. Bill Harris.

Link to study abstract.

Older adults with a higher BMI spread more infectious SARS-CoV-2 aerosol particles. www.pnas.org

Obesity Pollution COVID-19

The SARS-CoV-2 virus is transmitted through aerosols that are generated when an infected person breathes, talks, sneezes, or coughs. The amount and size of aerosol droplets a person exhales can vary drastically between individuals and may be affected by diet and age. Findings of a recent study suggest that humans and non-human primates with greater age and body mass index (BMI) produce more aerosol droplets during COVID-19 infection.

Aerosol droplets are produced when air passes over mucus-coated airways during breathing. This mucus determines the size of aerosol droplets produced. A healthy mucus layer forms large droplets, while a dysfunctional mucus layer produces droplets that aerosolize into many smaller infectious droplets. Mucus structure and composition are influenced by age, environment, disease, and the microbiota. A Western, obesity-promoting diet is often deficient in fiber, starving the beneficial bacteria in the gut that produce metabolites such as short chain fatty acids that regulate the lung mucus barrier. Older adults also experience degradation of the lung mucus layer, potentially influencing aerosol droplet size.

The researchers recruited 194 participants from the United States. They asked participants to breathe into a particle detector to measure the quantity of exhaled particles in the size range of three to five micrometers. They characterized participants who exhaled 156 particles per liter of air or less during the breath test as low spreaders and participants above this level of superspreaders. The particle detector was connected to an air filter that collected the particles so the concentration of SARS-CoV-2 virus could be measured. The investigators also used a sample of eight non-human primates to better understand the effects of SARS-CoV-2 infection. The investigators exposed rhesus macaques and green monkeys to either the SARS-CoV-2 or tuberculosis virus and monitored them for up to 60 days. The non-human primates performed a similar breath test as the one used in the human participants.

The authors found no relationship between sex and aerosol particle number; however, there were significant statistical relationships among age, BMI, and particle size. The strongest correlation was found between particle size and BMI-years, which is calculated as BMI multiplied by age. Participants in the bottom 50 percent for BMI-years exhaled significantly less aerosol than participants in the top 50 percent. In non-human primates, SARS-CoV-2 or tuberculosis infection increased the number of aerosol particles exhaled in proportion to the amount of viral RNA measured from mucus swabs.

The authors concluded that age, BMI, and active infection decrease aerosol particle size and may contribute to viral spread. Future models of pandemic progression should take these factors into account.

Link to full publication.

Exposure to air pollution increases depression risk. apple.news

Depression Pollution

Depression is a complex neuropsychiatric disorder that affects millions of people worldwide. Although many factors contribute to a person’s risk for developing depression, such as childhood trauma or stressful life events, genetic predisposition for the condition plays a prominent role. Findings from a recent study suggest that air pollution exerts harmful neuropsychiatric effects, especially among people genetically predisposed to depression.

Air pollution contains myriad toxic substances, including chemicals, gases, and particulate matter – a mixture of solid particles and liquid droplets that may have neurotoxic properties. Exposure to air pollution promotes oxidative stress and increases the risk of developing many chronic diseases, including cardiovascular disease, cancer, hypertension, and diabetes, markedly shortening people’s lives.

The new study involved 352 healthy adults living in Beijing, China, a city known for its high levels of air pollution and relatively homogeneous population. The investigators determined each participant’s genetic propensity for developing depression – referred to as a polygenic risk score – and tracked air quality near the participants' homes. Participants completed various mental tasks while undergoing brain scans.

The scans revealed that people who were exposed to air pollution performed poorly on mental tasks. This effect was more pronounced among those who had a higher polygenic risk score for depression as well as those exposed to the highest levels of air pollution. The findings held true even after considering other factors, such as age, sex, and education, which can influence depression risk.

These findings suggest that air pollution impairs neurocognitive function, especially among people genetically predisposed to depression. They also underscore public health efforts to ameliorate the harmful effects of pollution. Some evidence indicates that dietary components, such as omega-3 fatty acids and sulforaphane (a bioactive compound derived from broccoli), may negate some of the harmful effects of exposure to air pollution. Watch this clip in which Dr. Jed Fahey describes how sulforaphane provides protection from benzene, a carcinogenic compound present in air pollution.

Sulforaphane promotes urinary excretion of benzene, a common air pollutant. academic.oup.com

Pollution Sulforaphane NRF2

Sulforaphane promotes the production of glutathione, a powerful antioxidant that facilitates the body’s excretion of toxic substances. When glutathione binds with benzene, a known carcinogen present in air pollution, the two form mercapturic acids, which can be excreted and measured in urine. Findings from a 2019 study demonstrated that sulforaphane provided in a broccoli sprout beverage promoted excretion of benzene, as reflected in urinary mercapturic acid levels.

The intervention study involved 170 healthy adult participants between the ages of 21 and 65 years living in Qidong, China, an area known for its high levels of air pollution. The participants drank a placebo or a broccoli-sprout beverage containing one of three doses of sulforaphane – “high,” “medium,” or “low" – twice a day for a period of 10 days. After drinking the beverage, the participants provided a urine sample, which was assessed for benzene metabolites.

The authors of the study found that the high dose of sulforaphane markedly increased the production of several urinary metabolites. In particular, excretion of mercapturic acids increased by more than 63 percent in those taking the high dose. Mercapturic acid excretion in those who received the medium and low dose, however, was not significantly different from those who took the placebo.

These findings demonstrated that a broccoli sprout beverage containing sulforaphane enhanced the detoxication of benzene, an important airborne pollutant, and suggest that population-based strategies that employ a dietary approach are viable options for improving healthspan in humans.

Link to full study.

Nanoparticles in air pollution accumulate in the brains of young adults: A common denominator in neurodegenerative disease? www.sciencedaily.com

Alzheimer's Parkinson's Development Pollution

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the two most common neurodegenerative conditions in older adults, affecting a combined 36 million people worldwide. Evidence suggests that exposure to air pollution increases the risk of developing these diseases. Findings from a recent study demonstrate that particulate matter in air pollution accumulates in the brains of young adults and may serve as a common denominator in the pathophysiology of AD and PD.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. It is present in fine inhalable particles, with diameters that are generally 2.5 micrograms or less. Ultrafine particles less than 1 microgram in diameter, referred to as nanoparticles, are often enriched in highly reactive metals such as iron, aluminum, titanium, and others. They may serve as catalysts for reactive oxygen species formation and promote protein misfolding and aggregation. Nanoparticles in air pollution are not regulated and carry many health risks. They are also present in food additives and food packaging materials.

The authors of the study documented biomarkers of AD and PD present in brainstem samples taken during the autopsies of 186 healthy children and young adults (age range, 11 months to 27 years) living in the metro area of Mexico City, a region known for its high levels of air pollution. They also conducted magnetic remanence studies to quantify the presence of metal-rich nanoparticles in the brainstem samples. Finally, using high resolution scanning and transmission electron microscopy and energy-dispersive X ray analysis, they identified the composition, location, size, and shape of nanoparticles in the substantia nigra region of a randomly chosen single sample taken from the larger group. Damage to the substantia nigra is a hallmark of PD.

They found that all of the brainstem samples contained iron-, aluminum-, and titanium-rich nanoparticles. The quantity of nanoparticles varied among the brain samples, likely due to the level and duration of exposure. The authors posited that these nanoparticles could have been acquired via both oral and respiratory routes from food sources and airborne exposures, respectively. Damage to the mitochondria, endoplasmic reticulum, and neuromelanin in the single brainstem sample correlated with the presence of iron-, aluminum-, and titanium-rich nanoparticles.

These findings suggest that exposure to nanoparticles is pervasive, with evidence confirmed as early as 11 months of age. Such exposures may put people living in urban areas where high levels of air pollutants are present at greater risk for developing AD and PD.

Exposure to air pollutants may increase risk of death due to COVID-19. www.eurekalert.org

Pollution

Air pollution contains many toxic substances, including chemicals, gases, and particulate matter. Exposure to air pollutants is associated with poor health outcomes and increased risk of disease. Findings from a new study suggest that exposure to air pollutants, especially nitrogen dioxide, increases the risk of death due to COVID-19.

Nitrogen dioxide is a gaseous air pollutant composed of nitrogen and oxygen. Commonly measured in air in terms of parts per billion, nitrogen dioxide is often present in air in urban areas with heavy automobile traffic. Exposure to nitrogen dioxide is associated with increased susceptibility to respiratory infections.

To understand the relationship between exposure to key urban air pollutants (especially PM2.5, nitrogen dioxide, and ozone) and COVID-19 outcome, the authors of the study considered the case-fatality rate and the mortality rate – two major death outcomes associated with COVID-19. The case-fatality rate refers to how many of those with a confirmed diagnosis of COVID-19 die as a result of the disease. The mortality rate refers to the total number of COVID-19 deaths in the population.

They found that exposure to urban air pollutants increased risk of poor outcome in COVID-19 in a dose-dependent manner. For every 4.6 parts per billion increase of nitrogen dioxide in the air, the case-fatality rate increased more than 11 percent and the mortality rate increased more than 16 percent. The authors' analysis also revealed that reducing nitrogen dioxide exposure could have prevented nearly 15,000 deaths among those who tested positive for COVID-19.

These findings suggest that people living in urban areas where air pollution levels are high are at great risk of poor outcomes associated with COVID-19. They also support current efforts to reduce exposure to air pollutants in urban areas in the United States.

Another prominent component of air pollution is benzene. Research indicates that sulforaphane, a phytochemical derived from broccoli sprouts, promotes excretion of benzene. Watch this clip featuring Dr. Jed Fahey to learn more.

Link to full study.

Decreased exposure to air pollution associated with improved cognitive development and increases BDNF levels in children. www.sciencedaily.com

Brain Development Pollution BDNF

Exposure to air pollutants is associated with an increased risk of developing many health disorders, including heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections. Some evidence suggests that exposure to air pollution can impair neurological development in children. A 2014 study showed that reducing exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with improved cognitive development and increased BDNF levels in children.

Polycyclic aromatic hydrocarbons are produced during the combustion of coal, oil, gasoline, trash, tobacco, and wood. High-temperature cooking, such as grilling, promotes the formation of PAHs in meat and other foods. PAHs promote the formation of DNA adducts – covalent modifications of DNA that can drive carcinogenesis.

The study involved two cohorts of mother-child pairs who lived near a coal plant in China. One cohort of pairs was made up of 150 women who were pregnant while the coal power plant was operational and the other was made up of 158 women who were pregnant after it closed. None of the women smoked, and they all lived within 2.5 kilometers (about 1.5 miles) from the coal plant.

The authors of the study analyzed BDNF levels and their relationship to adduct formation and developmental outcomes in the two cohorts. They collected umbilical cord blood and maternal blood samples and measured the amount of DNA adducts in the samples. They also measured plasma levels of BDNF. When the children reached the age of two years, they underwent standardized testing that assessed motor, adaptive, language, and social development.

The children who were born to women who were pregnant after the plant closed had lower levels of PAH-DNA adducts, higher concentrations of BDNF, and higher developmental scores than those who were born to women who were pregnant when the plant was operational. Higher BDNF levels were associated with developmental scores. The findings suggest that reducing exposure to air pollutants during pregnancy lowers levels of PAH-DNA adducts and increases BDNF levels in infants.

Interestingly, clinical trials have demonstrated that sulforaphane, a compound derived from cruciferous vegetables (especially broccoli sprouts), can reduce the harmful effects of exposure to air pollutants (including PAHs) in humans. Sulforaphane works by switching on the activity of the body’s in-house detoxication pathways. Learn more about sulforaphane in this podcast featuring Dr. Jed Fahey.

Link to full study.

Perchlorate, a pollutant in water, harms human health. www.eurekalert.org

Pollution

Perchlorate, a chemical used to propel rockets and airbags, accumulates in the environment as a pollutant. A new study suggests that perchlorate can enter the water supply and might be more detrimental to human health than previously thought.

Perchlorate is transported from the blood into the thyroid gland by the sodium/iodide symporter, or NIS, which usually transports iodide and sodium. Iodide, the negatively charged form of iodine, is involved in producing thyroid hormone, which plays an important role in metabolism and development.

Previous research has demonstrated that sodium and iodide are co-transported by the NIS symporter in a two to one ratio in an energetically favorable reaction. The current study investigated the mechanism by which perchlorate affects the function of this transporter.

The authors of this cell culture study used radioactive iodine to determine how perchlorate influenced iodide transport across the NIS symporter. Using varying concentrations of perchlorate, they measured how much iodide was transported compared to sodium.

The authors found that perchlorate inhibited the transport of iodide in two ways. First, it competed with iodide for a receptor site. In a second mechanism, perchlorate altered the shape of the transporter by blocking one of the two sodium binding sites. Normally, iodide is co-transported into thyroid cells with two sodium ions, providing the energy required to drive iodide into the cell. When perchlorate blocks one of the sodium binding sites, a single sodium ion is transported with iodide in a less energetic reaction. This slower iodide transport means that less iodide reaches the thyroid gland leading to lower thyroid hormone production.

These findings suggest that perchlorate in the environment, even at low levels, can decrease the amount of iodide taken up by the thyroid gland. The resulting reduction in thyroid hormone production can be harmful to health, particularly to sensitive populations, including pregnant women, fetuses, and nursing infants.

Link to study abstract.

Global air pollution shortens people’s lives on a scale greater than warfare, other forms of violence, infection, and more. www.eurekalert.org

Pollution

Exposure to air pollution promotes oxidative stress and increases the risk of developing many chronic diseases, including cardiovascular disease, cancer, hypertension, and diabetes. Data from a new study indicate that ozone gas and particulate matter present in air pollution claim more lives than wars and other forms of violence by an order of magnitude.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. It is present in fine inhalable particles, with diameters that are generally 2.5 micrograms (PM2.5) or less. Ozone is a reactive, colorless gas with a strong odor. It irritates the respiratory system and may cause health problems by damaging lung tissue, reducing lung function, and sensitizing the lungs to other irritants, especially among the very young, very old, or those with compromised respiratory or immune function.

The authors of the study performed statistical analyses to investigate age-dependent increases in premature death rates and years of life lost from five categories of disease – lung cancer, lower respiratory illness, chronic obstructive pulmonary disease, heart disease, and stroke. The analyses were based on an atmospheric model that calculated worldwide exposure to PM2.5 and ozone gas, as well as mortality data from 41 cohort studies in 16 countries.

They found that nearly 9 million people die every year from air pollution-related causes, and more than one-third (35 percent) of these deaths occur in East Asia. The lowest death rates were in Australia, which has the most stringent air quality standards worldwide. Roughly 75 percent of air pollution-related deaths occur in people over the age of 60 years. The premature death rate exceeded that caused by warfare and other forms of violence, smoking, HIV/AIDS, parasitic and vector-borne diseases combined.

Other research suggests that sulforaphane, a compound derived from broccoli and other cruciferous vegetables, promotes the detoxication of some airborne pollutants and may provide a strategy to ameliorate their long-term health risks. Learn more about sulforaphane in this clip featuring Dr. Jed Fahey.

Link to full study.

Brake dust air pollution may have the same harmful effects on immune cells as diesel exhaust. www.eurekalert.org

Immune System Pollution

Air pollution from diesel exhaust contains a mixture of both toxic chemicals and particulate matter. Many studies have found associations between exposure to diesel exhaust and subsequent poor health outcomes such as increased asthma, heart disease, and cancer. Findings from a new study suggest that brake dust air pollution may have some of the same harmful effects on health as diesel exhaust.

Brake dust is a form of air pollution that consists of metal particles generated from mechanical abrasion from brakes. These particles are small enough to be inhaled deep into the lungs, where they drive the production of reactive oxygen species, promoting inflammation and altering the function of immune cells. Approximately 20 percent of the particulate matter in air pollution is from brake dust.

The study was conducted in macrophages (a type of immune cell) exposed to brake dust obtained from a brake pad testing factory. Following exposure to the dust, the macrophages were challenged with a bacterial pathogen to determine the cells' ability to initiate an immune response and carry out phagocytosis, the process by which macrophages engulf and destroy pathogens.

The cells demonstrated dose-dependent decreases in mitochondrial depolarization (a process that inhibits the production of mitochondrial reactive oxygen species), increased secretion of immune-related cytokines, and decreased phagocytosis. Following 24-hour incubation in a brake pad particle-free environment, the macrophages regained their ability to carry out an appropriate immune response.

Although this research was performed in cells and future research will need to confirm the effects brake dust has on animals, these findings suggest that exposure to brake pad abrasion particles may be as harmful as exposure to diesel exhaust. They also highlight the importance of pollution mitigation strategies in public health interventions.

Link to full study.

Depression and suicide linked to air pollution www.theguardian.com

Brain Depression Behavior Pollution

Air pollution contains a myriad of toxic substances. Exposure to air pollutants is associated with poor health outcomes and increased risk of disease. Findings from a recent review and meta-analysis suggest that high concentrations of particulate matter in air pollution may increase the risk of developing depression.

Depression is the most common mental health disorder worldwide, affecting approximately 322 million people – more than 4 percent of the global population. Between 2005 and 2015, rates of depression increased by more than 18 percent, and public health experts predict that by the year 2020, depression likely will rank second in the global burden of disease.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. Some evidence suggests that exposure to particulate air pollutants accelerates aging.

The authors of the review conducted a meta-analysis of 14 studies involving more than 680,000 participants living in North America, Europe, and Asia. They found that as concentrations of particulate matter increased, the risk of depression and suicide increased. Specifically, for every 10 microgram per cubic meter increase in particulate matter that is 2.5 microns or less in width, the risk of depression increased by 19 percent and risk of suicide increased by 5 percent.

The mechanisms that drive these links may be related to increased oxidative stress and neuroinflammation as a consequence of exposure to air pollutants. These findings point to the need for improving air quality and monitoring at-risk groups living in areas where air quality is poor.

Ozone air pollution was associated with a significant increase in emphysema. www.sciencedaily.com

Pollution

Ozone air pollution was associated with a significant increase in emphysema. Lung scans of more than 7,000 participants were compared across 6 metropolitan regions in the US and air pollution levels were measured at the homes of study participants.

This was a big study with analysis of more than 15,000 CT scans repeated on thousands of people over 18 years.

The study also found that if the ambient ozone level was 3 parts per billion higher where you live compared to another location over 10 years, that was associated with an increase in emphysema roughly the equivalent of smoking a pack of cigarettes a day for 29 years.

This study was a large prospective study so causation cannot be established. However, the authors developed novel and accurate exposure assessment methods for air pollution levels at the homes of study participants, collecting detailed measurement of exposures over years in these metropolitan regions, and measurements at the homes of many of the participants which strengthen the data.

New placebo-controlled trial finds that healthy adults given a broccoli sprout beverage high in sulforaphane had a 63% increase in benzene excretion. academic.oup.com

Cancer Pollution Sulforaphane NRF2 Glucoraphanin

A new placebo-controlled trial finds that healthy adults given a broccoli sprout beverage high in sulforaphane had a 63% increase in excretion in the carcinogen benzene which is a compound found in air pollution and tobacco smoke.

The study also showed that the sulforaphane’s role in benzene excretion was dose-dependant. The high sulforaphane dose increased benzene excretion by 63% and half the sulforaphane dose caused an 11% increase in benzene excretion.

The high dose broccoli sprout beverage contained 600 μmol of glucoraphanin (sulforaphane precursor) and 40 μmol sulforaphane, whereas the half dose contained 300 μmol of glucoraphanin and 20 μmol of sulforaphane.

I have referred to other studies showing similar effects of broccoli sprouts on benzene excretion. To learn more about how sulforaphane increases the excretion of carcinogens like benzene check out the in-depth episode we did on sulforaphane. https://www.foundmyfitness.com/episodes/sulforaphane

How Air Pollution Causes Diabetes - The Atlantic www.theatlantic.com

Diabetes Pollution

The particles examined in this study are known as PM2.5, or particulate matter that’s 2.5 micrometers big—30 times smaller than a human hair. They are emitted by various types of industry and fuel burning, but in the United States, the biggest source of PM2.5 is cars, says Ziyad Al-Aly, the study’s senior author and an assistant professor of medicine at Washington University at St. Louis. When there’s lots of PM2.5 in the air, the air might look smoggy or hazy. In lighter concentrations, the particles are invisible.

The study, published in The Lancet Planetary Health, linked data from 1.7 million American veterans who had been followed for a median of 8.5 years with air data from the EPA and NASA. It also aggregated past international research on diabetes and air pollution to devise a model to estimate diabetes risk based on the level of pollution, and it used the Global Burden of Disease study to estimate how many years of healthy life were lost due to this air-pollution-induced diabetes. Globally, 8.2 million years of healthy life were lost in 2016 to pollution-linked diabetes, it showed.

https://www.thelancet.com/journals/lanpla/article/PIIS2542-5196(18)30140-2/fulltext

Air Pollution, health, and genetic risk www.nature.com

Inflammation Genetics Pollution Environment

[Abstract] Uncovering the interaction between genomes and the environment is a principal challenge of modern genomics and preventive medicine. While theoretical models are well defined, little is known of the G × E interactions in humans. We used an integrative approach to comprehensively assess the interactions between 1.6 million data points, encompassing a range of environmental exposures, health, and gene expression levels, coupled with whole-genome genetic variation. From ∼1000 individuals of a founder population in Quebec, we reveal a substantial impact of the environment on the transcriptome and clinical endophenotypes, overpowering that of genetic ancestry. Air pollution impacts gene expression and pathways affecting cardio-metabolic and respiratory traits, when controlling for genetic ancestry. Finally, we capture four expression quantitative trait loci that interact with the environment (air pollution). Our findings demonstrate how the local environment directly affects disease risk phenotypes and that genetic variation, including less common variants, can modulate individual’s response to environmental challenges.

Prolonged exposure to air pollution below the US national safety standards is linked to a 7.3% increase in all-cause mortality. www.nejm.org

Pollution Mortality

Most of the studies on air pollution have included populations whose socioeconomic status is higher than the national average and who reside in well-monitored urban areas. This does not tell us what the health effects are of long-term exposure to low levels of air pollution in smaller cities and rural areas or among minorities or persons with low socioeconomic status (sensitive populations). This study involved 60 million people in the United States who receive Medicare and live in smaller cities or rural areas. This study showed that long-term exposures to particulate matter less than 2.5 μm and ozone were associated with a 7.3% increased risk of death, even at levels below the current annual national safety standards. In another study, the authors also looked at Medicare recipients and air pollution exposure risks and found that lifestyle factors such as smoking, BMI, and many other potential confounders did not change the data. With air pollution declining, it is critical to estimate the health effects of low levels of air pollution, below the current National standards, in order to determine whether these levels are adequate to minimize the risk of death. The Clean Air Act requires the EPA to set air quality standards that protect sensitive populations (such as those on Medicare) and studies like this may be important in order to inform regulatory policy going forward.

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