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Breast Milk

Breast milk and breastfeeding featured article

Nutrition in the first year of life is crucial to an infant's development and lifelong health. Early nutritional deficits are intrinsically linked to impaired mental and physical growth. Consequently, the risk of developing metabolic and cardiovascular diseases such as obesity, diabetes, and hypertension in childhood and later life is likely determined by early feeding and nutritional status.

Breastfeeding is the biologically superior way to feed an infant. The American Academy of Pediatrics recommends exclusive breastfeeding for the first six months of an infant's life and continued breastfeeding while introducing age-appropriate foods until an infant is 12 months old or older. This provides the infant optimal nutrition and immunity while supporting growth and development.

Breastfeeding provides many benefits to infants and mothers. For example, research in developing and industrialized nations demonstrates that breastfeeding is associated with reduced risk of...

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breast milk

The effects of nicotine and cigarette smoke exposure on breast milk and breastfeeding

Posted on April 3rd 2022 (over 3 years)

In this clip, Dr. Rhonda Patrick describes some of the harmful effects of nicotine and cigarette smoke exposure on breast milk quality and breastfeeding duration.

breast milk

Breast milk contains stem cells, which can be passed to the infant | The Biology of Breast Milk

Posted on April 3rd 2022 (over 3 years)

In this clip, Dr. Rhonda Patrick describes the strange phenomenon and role of mammary stem cells in breast milk.

breast milk

Beneficial microbes are transferred to the baby while breastfeeding | The Biology of Breast Milk

Posted on April 3rd 2022 (over 3 years)

In this clip, Dr. Rhonda Patrick describes the unique community of microbes present in human breast milk.

Topic Pages

  • Nicotinamide riboside

    Breast milk contains nicotinamide riboside, a bioavailable NAD⁺ precursor absorbed enterally to support neonatal NAD⁺ biosynthesis and metabolism.

News & Publications

  • 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.

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  • Polystyrene nanoplastic exposure alters breast milk proteins, potentially impairing neurodevelopment in breastfed infants. www.utep.edu
    Nutrition Development Vitamin A Breast Milk

    Beta-lactoglobulin is a protein in breast milk. It binds to retinol, a form of vitamin A that plays a crucial role in neurodevelopment, facilitating its transport. A recent study found that nanoplastic exposure induces structural changes in beta-lactoglobulin, impairing retinol binding and transport.

    Researchers conducted a multi-part study to investigate the effect of polystyrene nanoparticles on beta-lactoglobulin. First, they measured changes in the protein’s structure and its ability to bind retinol. Then, they examined polystyrene’s effects on lysozyme, an antibacterial protein found in breast milk. Finally, they assessed the effects of polystyrene exposure in worms.

    They found that polystyrene nanoparticles induced dose-dependent structural changes in beta-lactoglobulin, impairing its ability to bind to retinol. They identified similar structural abnormalities in lysozyme, driving the formation of amyloid fibrils (abnormal protein clumps). In worms, polystyrene impaired movement, similar to the effects of the neurotoxin paraquat.

    These findings suggest that polystyrene nanoparticles alter breast milk protein structures and functions, potentially driving nutritional deficiencies and neurological damage.

    Coming soon: a comprehensive overview article on microplastics.

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  • THC from a single use of cannabis accumulates in breast milk for up to 12 hours in breastfeeding women. news.wsu.edu
    Cannabinoid Development Breast Milk

    Breastfeeding is the biologically superior way to feed an infant. However, harmful substances in the mother’s blood can transfer to and accumulate in her breast milk. A recent study found that tetrahydrocannabinol (THC), the primary psychoactive ingredient in cannabis, accumulates in breast milk after a single use, persisting for several hours.

    The study included 20 healthy young women who were breastfeeding their infants and used cannabis at least once weekly. Participants collected samples of their breast milk after abstaining from cannabis use for at least 12 hours and at several intervals over an eight- to 12-hour period after use.

    Researchers found that participants' breast milk contained THC even after 12 hours of abstention. THC concentrations peaked about two hours after cannabis use; however, in some cases, concentrations peaked as early as half an hour after use. Concentrations were higher with multiple uses and remained elevated throughout the 12-hour study period. On average, infants received approximately 16.2 micrograms per kilogram of body weight of THC over 12 hours.

    These findings suggest that THC accumulates in breast milk after a single use of cannabis. The effects of THC on the developing infant brain are unclear. However, research on rodents has identified lasting, mild effects on memory and learning following a single, extremely low dose of THC equivalent to 0.2 micrograms per kilogram in humans – far less than the average dose the infants in this study received. Other harmful compounds, including nicotine, caffeine, and heavy metals, can pass into breast milk, too. Learn more about breast milk and breastfeeding in our overview article.

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  • Flaxseed oil supplementation boosts levels of some omega-3 fatty acids but not DHA in lactating women. pubmed.ncbi.nlm.nih.gov
    Omega-3 Development Breast Milk

    Flaxseed oil is rich in alpha-linolenic acid (ALA), a precursor to docosahexaenoic acid (DHA), an omega-3 fatty acid critical for infant brain and eye development. A recent study found that supplementing the diets of lactating women with flaxseed oil altered the levels of some omega-3 fatty acids in breast milk, plasma, and red blood cells but not DHA.

    The study involved seven lactating women who consumed 20 grams of flaxseed oil daily for four weeks. Researchers collected and analyzed samples of the participants' breast milk and blood before, during, and after the supplementation period to assess changes in fatty acid composition.

    They found that levels of ALA, eicosapentaenoic acid (EPA), and docosapentaenoic acid (DPA) increased considerably in the participants' breast milk, plasma, and red blood cells throughout the study. However, DHA levels were not significantly altered in any of the assessments.

    These findings suggest that dietary supplementation with flaxseed oil in lactating women boosts the presence of omega-3 fatty acids ALA, EPA, and DPA in breast milk and blood. However, flaxseed oil supplementation does not influence DHA levels, highlighting the complexity of fatty acid conversion and the need for further research into dietary strategies that could enhance DHA content in lactating women.

    DHA is the most abundant omega-3 fatty acid in a newborn’s brain and influences mental and psychomotor development. ALA can be converted to DHA in the body, but the conversion rate is notably low. The mother’s diet and lifestyle strongly influence the quantity of DHA in breast milk. Learn more about breast milk and breastfeeding in our overview article.

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  • Breastfeeding for six months or more appears to reduce the risk of cardiovascular problems developing in mothers for at least three years after delivery, according to new study. www.scimex.org
    Metabolic Syndrome Breast Milk Cardiovascular

    Breastfeeding benefits mothers by promoting post-partum weight loss and reducing the risk of certain types of cancer later in life. A new study suggests that breastfeeding also supports maternal cardiometabolic health. Women who breastfed for at least six months were leaner and had lower blood pressure than those who didn’t.

    Researchers conducted health check-ups on 160 mother-child pairs enrolled in Screening Tests to Predict Poor Outcomes of Pregnancy, a long-term study that assessed women’s risk for pregnancy complications. They assessed the women’s cardiometabolic health via blood pressure, body measurements, and serum metabolic markers (glucose and lipids). They determined breastfeeding duration via the children’s health records.

    They found that the cardiometabolic health of women who breastfed for at least six months was considerably better than those who did not breastfeed, as evidenced by lower body mass index (BMI) and blood pressure. These differences persisted even after considering factors like BMI, socioeconomic status during early pregnancy, prenatal smoking, and maternal age during early pregnancy. In women who had experienced pregnancy complications (such as preeclampsia or gestational diabetes), breastfeeding for at least six months reduced blood pressure, insulin, and triglycerides, while increasing HDL cholesterol levels.

    These findings suggest that breastfeeding for a minimum of six months benefits the cardiovascular health of mothers, particularly those who experienced pregnancy complications. They also highlight the importance of breastfeeding as a potential means to reduce the risk of cardiovascular issues in women following childbirth. However, the investigators conceded that this was a small study, potentially hindering its translatability to a broad audience. Learn more about the maternal benefits of breastfeeding in our overview article.

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  • Breast milk lipid molecule stimulates brain stem cells to produce oligodendrocytes, effectively reversing white matter damage in neonatal mice. corporate.dukehealth.org
    Brain Development Breast Milk

    Premature infants are at greater risk for developing cerebral palsy, a motor disability caused by brain injury-related white matter losses, impairing movement, balance, and posture. However, a new study in mice indicates that a cholesterol-like molecule present in breast milk may protect against cerebral palsy. Mice administered breast milk were protected from the harmful effects of white matter losses.

    Researchers tested the ability of several oxysterols (naturally occurring cholesterol-like molecules) in human breast milk to promote the production of oligodendrocytes, a type of cell that stimulates white matter development. They found that the oxysterol 20-alpha hydroxycholesterol induced oligodendrocyte production through the sonic hedgehog pathway – a well-known pathway involved in neurodevelopment.

    Then, they gave neonatal mice that had experienced inflammation-driven brain injury and subsequent white matter losses 20-alpha hydroxycholesterol. They found that the compound promoted white matter formation, reversing the animals' brain injuries.

    These findings suggest that 20-alpha hydroxycholesterol, a compound present in breast milk, influences neonatal white matter development and may benefit infants at risk for cerebral palsy or other brain injury-related disorders. Learn more about the benefits of breast milk in our overview article.

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  • Breastfeeding for 12 months or more linked to higher math and English test scores in 16-year-olds. healthnews.com
    Development Breast Milk

    Breastfeeding profoundly affects an infant’s brain, greatly influencing intellectual development. A new study shows that longer breastfeeding improves children’s academic performance. Children who breastfed for longer duration performed better on standardized tests than those who breastfed for shorter periods.

    Researchers drew on data from the Millennium Cohort Study, which included 5,000 children born in England between 2000 and 2002. They looked at how long each child was breastfed (based on their mothers' reports) and how well they performed on standardized tests around the age of 16 years.

    They found that children who breastfed for longer tended to perform better on standardized tests of math and English, even after considering factors like socioeconomic status and maternal cognitive ability. In addition, children who breastfed for at least four months scored an average of two to three points higher on standardized tests than children who never breastfed.

    These findings suggest that breastfeeding for a longer duration modestly improves academic performance later in life. Learn more about the benefits of breastfeeding in our comprehensive overview article.

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  • Babies breastfed for at least three months are less likely to get sick. bmcpublichealth.biomedcentral.com
    Immune System Development Breast Milk

    Breastfeeding protects infants from many common illnesses, a new study has found. Babies breastfed for at least three months were less likely to spend time in the hospital or develop asthma, colds, ear infections, or other common conditions.

    Researchers tracked the health and breastfeeding histories of nearly 4,000 children living in Ireland. They compared the rates of hospitalization and illnesses of babies fed breast milk exclusively for 90 days or more to those who never breastfed.

    They found that babies breastfed for 90 days or more were less likely to develop chest infections, common colds, ear infections, asthma, respiratory problems, eczema, skin allergies or problems, vomiting, and colic, compared to those who never breastfed. Breastfed babies were also less likely to require medical treatment or be hospitalized.

    These findings support the practice of breastfeeding for optimal infant health. They also underscore the benefits of breast milk, even for infants born in a developed nation.

    Breast milk is a complex, dynamic fluid that contains nutritional and non-nutritional components that positively influence an infant’s health and development. These components work together synergistically to supply a compensatory immune “system” that includes antimicrobial and anti-inflammatory agents, immunomodulatory factors, leukocytes, and others. Learn more about breast milk and breastfeeding in our overview article.

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  • Breastfeeding for longer duration boosts cognitive performance later in life. journals.plos.org
    Development Intelligence Breast Milk

    Children who were breastfed for 12 months or longer scored higher on standardized intelligence tests – even in their teens, according to a new study. These findings held true even after considering other factors that might influence intelligence.

    Researchers asked the mothers of more than 7,800 children living in the United Kingdom how long they breastfed their children. They collected information about each mother’s socioeconomic status and cognitive abilities and administered standardized intelligence tests to the children at the ages of 5, 7, 11, and 14 years.

    They found that across the board, longer-duration breastfeeding – 12 months or more – improved children’s performance on intelligence tests at all ages, even up to the age of 14 years. After considering factors that might influence the children’s cognitive performance, such as the mother’s socioeconomic status or intelligence, the researchers found that compared to non-breastfed children, children who were breastfed for longer periods performed modestly higher on intelligence tests from early childhood into their teen years.

    Breastfeeding is the biologically superior way to feed an infant. Evidence suggests that breastfeeding has profound effects on the developing infant’s brain, promoting increases in white matter volume, especially in parts of the brain associated with language, emotional regulation, and cognition.

    This study’s findings suggest that breastfeeding for longer duration influences an infant’s cognitive performance later in life. Learn more about the benefits of breastfeeding in our overview article.

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  • Fast food diet before pregnancy can impact breast milk and baby’s health www.joh.cam.ac.uk
    Diet Breast Milk Lactate

    Fast food during pregnancy harms both mother and offspring and interferes with milk production.

    Fast foods – burgers, fries, pizzas, sugar-sweetened drinks, and many others – are often high in calories, saturated fat, added sugars, and salt. Regular consumption of fast foods is associated with an increased risk for many chronic diseases. Findings from a recent study suggest that eating fast food during pregnancy negatively influences maternal health during pregnancy and undermines the nutritional quality of a mother’s breast milk.

    Breast milk is a complex and highly dynamic fluid that changes in composition in response to the growing infant’s needs. It contains both nutritional and non-nutritional components and is profoundly influenced by maternal health and dietary intake.

    The investigators fed one group of mice a high-fat, high-sugar diet that mimicked the nutritional content of fast food before, during, and after pregnancy. They fed another group a normal diet. They assessed the mothers' metabolic health, milk output, and milk composition, and assessed the offspring’s health.

    They found that the mice that ate the high-fat, high-sugar diet were heavier and had higher blood glucose and insulin levels during pregnancy than the mice that ate the normal diet. They also had fatty livers and showed signs of changes in their pancreatic tissues. More of the offspring born to the mice that ate the high-fat, high-sugar diet died during the lactation period due to poor maternal mammary gland development and diminished milk protein production.

    These findings suggest that eating foods that are high in fat and sugar (such as fast foods) during pregnancy negatively influences maternal health and undermines the nutritional quality of a mother’s breast milk. Learn more about breast milk and breastfeeding in our overview article.

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  • Babies Breastfed for a Year or More Better Protected Against Adult Obesity www.newsweek.com
    Obesity Development Breast Milk

    Breastfeeding for a year or longer protects infants against obesity in later life.

    Obesity is a condition in which a person has too much body fat. Having obesity increases a person’s risk for many chronic diseases, including diabetes, heart disease, cancer, and others. New research suggests that breastfeeding for a year or longer protects infants against obesity in later life.

    Breastfeeding is the biologically superior way to feed an infant. The American Academy of Pediatrics recommends exclusive breastfeeding for the first six months of an infant’s life and then continued breastfeeding while introducing age-appropriate foods until an infant is 12 months old or older. This provides the infant optimal nutrition and immunity while supporting growth and development.

    To model short-term versus long-term breastfeeding in humans, the investigators weaned one group of rat pups at three weeks of age (typical weaning time) and another group at four weeks of age (delayed weaning time, comparable to a year or more in humans). Once the animals were weaned, half of each group were fed a normal diet, and half were fed a high-fat diet until they reached adulthood. The investigators measured the animals' bodyweight, analyzed their body composition, and measured their energy expenditure.

    They found that rats that ate a normal diet and were weaned at the typical and delayed times did not differ in terms of bodyweight in adulthood. But rats that had a delayed wean time and were fed a high-fat diet were leaner than those that were weaned at the typical time and fed a high-fat diet. The delayed rats also had higher energy expenditures and more active brown fat, a type of fatty tissue involved in thermogenesis, or heat production. The delayed rats' brown fat contained higher quantities of various proteins involved in thermogenesis, including fibroblast growth factor 21 (FGF21). FGF21 activates neurons in the brain involved in metabolic regulation.

    These findings suggest that prolonged breastfeeding protects against obesity in later life, likely mediated by the influence of FGF21 on metabolic regulation. Learn more about the beneficial effects of breastfeeding for both infants and mothers in our overview article.

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  • Longer periods of lactation (breast feeding) may promote lower visceral and pericardial fat, an effect that persists many years through midlife www.sciencedaily.com
    Cancer Pregnancy Development Breast Milk Visceral Fat

    Breastfeeding may reduce fatty deposits around the heart and other organs.

    The benefits of breastfeeding on infant health are widely known, but breastfeeding benefits maternal health, too. For example, evidence suggests that women who breastfeed experience a faster return to pre-pregnancy weight and have a lower risk of developing cardiovascular disease and certain types of cancer Findings from a 2021 study suggest that breastfeeding is associated with having less pericardial and visceral adipose tissue.

    Pericardial adipose tissue is fat that accumulates in and on the pericardium – the membrane that surrounds the heart. Visceral adipose tissue is fat that is stored in the abdominal cavity near the liver, pancreas, and intestines. Evidence suggests that pericardial and visceral fat produce adipokines, cell-signaling molecules that drive metabolic dysfunction.

    The investigators drew on data from the Coronary Artery Risk Development in Young Adults study, an ongoing examination of the risk factors for cardiovascular disease in young adults living in the United States. The participants included 910 women who had given birth at least once during the 25 years of follow-up. They provided information about their reproductive histories, overall health, lifestyles, and how long they breastfed. The investigators used computed tomography to measure the women’s body fat.

    They found that women who breastfed had less pericardial and visceral fat than women who did not, even when considering the women’s age, race, smoking status, body mass index, fasting glucose, family history of diabetes, fat intake, total cholesterol, and physical activity. The protective effects of breastfeeding were duration-dependent, with longer-duration breastfeeding exerting greater effects, and appeared to last through midlife.

    These findings suggest that breastfeeding is associated with having less pericardial and visceral adipose tissue. Learn more about the benefits of breastfeeding in our overview article.

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  • Density of carotenoid pigments in the eye predicts levels breast milk. www.mdpi.com
    Eyes Carotenoids Breast Milk

    “Pregnancy and lactation can change the maternal nutrient reserve. We evaluated the association of macular pigment optical density (MPOD) with dietary and breastmilk carotenoids in postpartum women.

    MPOD measurements and dietary intake of five carotenoids were obtained from 80 mothers in the first three months postpartum. Breastmilk samples from a subset of mothers were analyzed to determine their nutrient composition. The association between MPOD and dietary or breastmilk carotenoids was quantitatively assessed to better understand the availability and mobilization of carotenoids.

    Our results showed that dietary α-carotene was positively correlated with MPOD. Of the breastmilk carotenoids, 13-cis-lutein and trans-lutein were correlated with MPOD when controlled for the total lutein in breastmilk. Other carotenoids in breastmilk were not associated with MPOD. Maternal MPOD is positively correlated with dietary intake of α-carotene in the early postpartum period, as well as with the breastmilk content of lutein."

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  • Compound that lends spiciness to pepper transfers to breast milk, potentially influencing infant food choices in later life. www.sciencedaily.com
    Nutrition Breast Milk

    Breast milk is a complex and highly dynamic fluid that contains both nutritional and non-nutritional components. Some of these components provide breast milk aroma and taste aspects, such as those associated with garlic or coffee, potentially influencing the breastfed infant’s dietary preferences later in life. Findings from a new study suggest that the non-nutritional compound piperine transfers into breast milk, providing pungent flavor aspects.

    Piperine is a bioactive compound found in black pepper that exerts anti-inflammatory, anti-pain, and anti-arthritic properties. Evidence indicates that piperine potentiates the beneficial health effects of curcumin, a bioactive compound found in turmeric.

    Pungency is a sensory aspect of food, often referred to as spiciness, heat, or “bite.” Pungent compounds elicit their effects by triggering a specific protein in the mouth, called the TRPV1 receptor. Interestingly, repeated piperine exposure desensitizes the TRPV1 receptor.

    The study involved 18 healthy breastfeeding mothers (average age, 32 years). Each of the mothers consumed a dish (referred to as a “curry”) containing a mixture of pungent ingredients, including red chili, ginger, piperine, and turmeric. The mothers provided breast milk samples one hour before consumption of the curry and again at one, two, and three hours afterward. The investigators assessed the milk for the presence of pungent compounds using mass spectrometry.

    They found that piperine transferred to the breast milk but in concentrations far below the taste threshold for adults. However, the authors noted that despite the low concentrations, piperine would still interact with the infant’s TRPV1 receptors, potentially desensitizing them and contributing to greater tolerance to piperine later in life.

    In a related study, the investigators found that aroma compounds present in the curry dish transferred to breast milk, altering the milk’s aroma. Taken together, these findings suggest that non-nutritive substances present in a breastfeeding mother’s diet transfer to her milk, potentially influencing dietary preferences later in her infant’s life. Learn more about the composition of breast milk in our overview article.

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  • Sugars found in human breast milk boost cognitive flexibility. www.tandfonline.com
    Nutrition Development Breast Milk

    Breastfeeding during early childhood is associated with positive life outcomes, ranging from improved metabolic health to greater cognitive ability. Researchers believe this effect stems from human breast milk being particularly rich in indigestible sugars, many of which are exclusive to the human species and known as human milk oligosaccharides (HMOs). Now, a new study reports that a particular class of HMOs may be uniquely crucial – at least when it comes to cognitive development.

    The researchers conducted their study in piglets, whose anatomical and cognitive development resembles that of human children. Starting at two weeks of age, piglets were randomly selected to receive one of four milk replacement formulas: a control formula mimicking the oligosaccharide composition of pig milk, and three others containing various types of HMOs.

    Eight weeks later, piglets were transitioned to a solid diet and trained on a challenging memory task that required them to remember which four out of 16 possible locations in a large arena contained hidden food rewards. For an extra challenge, they started each new trial from a different drop-off point, which meant that they had to actively engage with their surroundings to navigate to the rewarded spots.

    Then the animals completed a test of cognitive flexibility – the ability to adapt to changing environments and rules. The researchers baited a new set of four locations with the food rewards and watched how quickly piglets reacted to the change. They found that the piglets that had consumed formula containing sialylated HMOs (HMOs containing a special sugar called sialic acid) were better learners than their peers, especially those whose formula mimicked pig milk. This last group were slowest to learn the new reward locations and more likely to accidentally re-visit spots where they had already collected a reward – a sign of short-term memory lapse.

    These results suggest that sialylated HMOs are a particularly crucial component of breast milk for the development of flexible cognition. This effect might be underpinned by the oligosaccharides' high content of sialic acid, which is found in brain cell membranes and implicated in regulating cellular communication, developmental gene activity, and myelination, (the process of coating neuronal axons in fatty tissue that speeds up signaling). Learn more about HMOs and other beneficial components of breast milk in this episode featuring Dr. Rhonda Patrick.

    Link to full publication

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  • "Decoy" proteins in amniotic fluid and breast milk protect fetuses and infants from severe COVID-19. medicalxpress.com
    COVID-19 Breast Milk

    Most pregnant women who develop COVID-19 experience mild or asymptomatic illness and rarely transmit the disease to their infants in utero or postpartum. Findings from a new study suggest that specialized “decoy” proteins in amniotic fluid and breast milk protect fetuses and newborns from severe COVID-19.

    SARS-CoV-2, the virus that causes COVID-19, gains entry to cells via various receptor proteins, including angiotensin-converting enzyme 2 (ACE2), CD26, CD147, and neuropilin-1 (NRP-1), among others. These proteins are typically embedded in cellular membranes, but they can also be found in soluble form, existing freely in bodily fluids. Some evidence suggests that soluble forms of ACE2, in particular, serve as “viral traps,” or decoys, effectively preventing SARS-CoV-2 from interacting with membrane-bound forms.

    The authors of the study analyzed amniotic fluid (collected at 37 weeks' gestation) and breast milk (collected at two and six weeks postpartum) that had been stored prior to the COVID-19 pandemic. They centrifuged the samples and then measured the amount of soluble ACE2, CD26, CD147, and NRP-1 present.

    Their analysis revealed that all the samples contained an abundance of the soluble forms of the various proteins. Amniotic fluid contained more CD26 than breast milk, but breast milk contained higher amounts of ACE2 and NRP-1. In addition, the soluble proteins in amniotic fluid were of different isoforms (shorter) than those in breast milk. These findings suggest that soluble receptors in breast milk and amniotic fluid act as decoy receptors to reduce the risk of SARS-CoV-2 infection and/or severe COVID-19 outcomes in fetuses and infants.

    Interestingly, human milk oligosaccharides (HMOs) in breast milk serve as decoys to protect the infant from gut infections. In order for pathogenic bacteria to cause infection, they must first target and bind to specific carbohydrates found on the cells that line the gut. However, the overall structure and shape of HMOs mimics that of the carbohydrate targets. The pathogens bind to the HMOs, instead, foiling their ability to establish themselves in the gut. Learn more about HMOs and other immunomodulatory aspects of breast milk in our overview article.

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  • Vaccine-based mRNA does not pass into breast milk. jamanetwork.com
    Pregnancy Breast Milk

    Maternal exposures during lactation influence the composition of a woman’s breast milk. Out of concern that the mRNA in mRNA-based COVID-19 vaccines could pass into breast milk and alter infant immunological development, many lactating women have declined vaccination against COVID-19 or have stopped breastfeeding prior to vaccination. Findings from a new study indicate that mRNA from an mRNA-based vaccine does not pass into breast milk.

    mRNA-based vaccines contain the genetic instructions for synthesis of a single viral protein that, when injected into the body, stimulates the immune system to make antibodies against a specific target. The mRNA is housed in lipid nanoparticles to protect it, and because mRNA can’t enter a cell’s nucleus, concerns about its safety are low. Robust evidence indicates that the mRNA-based vaccines against COVID-19 are highly effective, and a small, prospective cohort study found that maternal vaccination may provide protection against COVID-19 in breastfed infants.

    The current study involved seven lactating women (average age, 37 years) who were scheduled to receive either the Pfizer BioNTech or Moderna mRNA-based vaccines against COVID-19. The women provided breast milk samples prior to vaccination and between four and 48 hours afterward. The samples were chilled or frozen until they were analyzed for mRNA content via real-time quantitative polymerase chain reaction assay.

    Analysis of the breast milk samples revealed that none of the samples contained detectable levels of vaccine mRNA. The authors of the study posited that if small quantities of mRNA were present in the breast milk (below the detection limits of their assay), they would likely be broken down in the infant gut. Although this was a very small study, these findings suggest that mRNA-based vaccines against COVID-19 are safe for lactating women and their infants, but further study in larger groups is warranted.

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  • Sugar present in breast milk promotes myelin repair in multiple sclerosis. www.eurekalert.org
    Multiple Sclerosis Breast Milk

    Myelin, a fatty substance that insulates nerve axons and facilitates nerve signal conduction, is produced by the oligodendrocytes of the central nervous system. Myelination, the process of accruing myelin, begins early in life and plays a critical role in cognitive development and life-long neuronal function. Findings from a new study suggest that N-acetylglucosamine, a sugar present in breast milk and widely available as a dietary supplement, promotes remyelination in people who have multiple sclerosis.

    Multiple sclerosis is an immune-mediated disorder characterized by an inability to remyelinate nerve axons subsequent to inflammatory damage. Symptoms of the disease vary and can include numbness or tingling in the limbs, difficulty walking, fatigue, and problems with vision and speech, among others. The disease affects more than 2 million people worldwide.

    The rodent study investigated the role of N-acetylglucosamine in a mouse model of multiple sclerosis. The authors of the study gave mice either N-acetylglucosamine or a placebo in their drinking water for three days. They assessed the mice for nerve axon damage and impaired motor function (likelihood of falling) while the mice walked on a spinning rod.

    The authors found that administration of N-acetylglucosamine protected nerve axon damage and prevented motor function losses in the mice that received the N-acetylglucosamine. They also reported unpublished data indicating that people with multiple sclerosis who have low levels of serum N-acetylglucosamine typically experience a more progressive disease course and greater disability than those with higher levels of the compound.

    Taken together, these findings demonstrate that N-acetylglucosamine may be beneficial in treating people who have multiple sclerosis. More research is needed to confirm this possibility.

    Interestingly, some evidence suggests that people who have multiple sclerosis experience functional improvements with the fasting-mimicking diet, a dietary strategy that promotes immune cell turnover. Learn more about the fasting-mimicking diet and multiple sclerosis in this clip featuring Dr. Valter Longo.

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  • Breast milk components affect infant growth and help prevent obesity in early childhood. www.eurekalert.org
    Pregnancy Breast Milk

    Breastfeeding is the biologically superior way to feed an infant. The American Academy of Pediatrics recommends exclusive breastfeeding for the first six months of an infant’s life and then continued breastfeeding while introducing age-appropriate foods until an infant is 12 months old or older. This provides the infant optimal nutrition and immunity while supporting growth and development. New research shows that components of breast milk called human milk oligosaccharides may influence infant growth and prevent obesity in early childhood.

    Human milk oligosaccharides, or HMOs, are complex, indigestible sugars present in breast milk. More than 200 HMOs have been identified, and they are the third most abundant factor in breast milk after fat and lactose. The quantity and composition of the HMOs in breast milk are genetically determined and differ slightly between women. The primary role of HMOs is to serve as prebiotics – compounds that induce the growth or activity of beneficial bacteria – in the infant gut. In turn, these beneficial bacteria produce short-chain fatty acids and other substances that prevent the colonization of pathogenic bacteria in the gut.

    The study analyzed more than 800 breast milk samples from women enrolled in a prospective population-based birth cohort study in Finland. The authors of the study then analyzed growth data for children from age 3 months to 5 years old and linked it to their mothers' HMO composition to test for associations.

    The analyses revealed that high concentrations of an HMO called 2'-Fucosyllactose (2'FL) and low concentrations of an HMO called Lacto-N-neotetraose (LNnT) influenced growth in infancy and early childhood. In particular, HMO diversity and the concentration of LNnT were inversely associated. In addition, concentrations of 2′FL were directly associated with child height and weight between the ages of 3 and 12 months. Watch this clip in which Drs. Erica and Justin Sonnenberg describe some of the beneficial properties of HMOs.

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  • Infants given formula containing milk fat globule membranes (found in human breast milk) scored better on tests of cognitive, language & motor skills. news.ku.edu
    Pregnancy Protein Breast Milk

    The fatty acids in breast milk are encapsulated in fat globules surrounded by a triple-layered structure called a milk fat globule membrane, or MFGM. The MFGM is interspersed with a variety of proteins, enzymes, and cholesterol that confer many of the antibacterial and anti-inflammatory properties of breast milk – the gold standard of infant nutrition.

    MFGM influences many aspects of infant growth, especially cognitive development. Unfortunately, most infant formulas do not contain MFGM. However, a recent clinical trial found that MFGM from cows' milk exerts similar beneficial effects on human infants when included in infant formula. The double-blind, randomized, controlled trial involved 451 healthy, full-term infants who received either regular formula or formula containing MFGM and lactoferrin (a protein found in human and cows' milk) at concentrations similar to human milk.

    At the end of the 18-month-long study, the infants who received formula with the MFGM and lactoferrin scored higher on cognitive, language, and motor development tests than infants who received ordinary formula. In fact, their scores were similar to those observed in children who were breastfed, suggesting that the addition of MFGM and lactoferrin to infant formulas could narrow the gap in cognitive development commonly observed between formula-fed infants and breastfed infants.

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