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Coffee

Episodes

Posted on June 9th 2025 (8 days)

Dr. Rhonda Patrick discusses coffee's remarkable ability to slow biological aging, reduce DNA damage, and lower cancer risk.

Posted on May 30th 2023 (about 2 years)

Heat therapy (saunas, exercise, hot baths) can enhance slow-wave sleep. This video explores exercise and heat's joint role in sleep regulation.

Posted on October 1st 2022 (over 2 years)

Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.

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News & Publications

  • That morning cup of coffee might do more than boost alertness—it might promote longevity. While many studies link moderate coffee drinking to better health, the timing of those effects is less clear. However, a recent study found that morning-only coffee drinkers were more than 30% less likely to die from cardiovascular disease.

    Researchers analyzed data from more than 40,000 adults in the National Health and Nutrition Examination Survey and 1,400 adults in the Women’s and Men’s Lifestyle Validation Study. They searched for patterns in the timing of coffee consumption and tracked participants for an average of nearly 10 years to monitor deaths from all causes, cardiovascular disease, and cancer.

    Two coffee-drinking patterns emerged: a morning-only pattern (4 a.m. to noon) and an all-day pattern. Compared with people who didn’t drink coffee at all, those who drank coffee only in the morning had a 16% lower risk of dying from any cause and a 31% lower risk of dying from cardiovascular disease, indicating that the health benefits of drinking more coffee were strongest among morning-only drinkers. Surprisingly, caffeine didn’t explain the difference. When the researchers adjusted for both caffeinated and decaffeinated coffee intake, the timing of coffee drinking still mattered.

    These findings suggest that drinking coffee earlier in the day offers more health benefits than drinking it over the course of the day. Coffee induces autophagy–a critical process that helps reduce the risk of cancer and other chronic diseases. Learn more in this clip featuring Dr. Guido Kroemer.

  • Drinking your daily cup of coffee or tea might do more than give you a boost—it could lower your risk of developing multiple serious cardiometabolic conditions simultaneously, like diabetes, heart disease, or stroke. A recent study found that moderate coffee or caffeine consumption may cut your risk of cardiometabolic multimorbidity by as much as 50%.

    Researchers analyzed data from more than 172,000 participants enrolled in the UK Biobank who had no cardiometabolic diseases at the start. Participants reported their coffee, tea, and caffeine consumption; about half provided blood samples for metabolic marker analysis.

    They found that people who drank about three cups of coffee daily (or consumed 200 to 300 milligrams of caffeine daily) were 40% to 50% less likely to develop multiple cardiometabolic diseases than those who drank little or no caffeine. They also discovered that specific blood markers, such as certain lipid components, were linked to coffee and caffeine consumption and a lower risk of cardiometabolic conditions.

    These findings suggest that moderate coffee or caffeine intake reduces the risk of developing cardiometabolic diseases but also slows their progression if they occur. Other evidence points to the many health benefits associated with coffee and caffeine, but it’s crucial to remember their effects on sleep. Learn more in this Aliquot featuring Drs. Guido Kroemer, Satchin Panda, Elissa Epel, Matthew Walker, and Rhonda Patrick

  • Coffee is perhaps best known for its stimulant properties, primarily from its caffeine content. Recent research found that caffeine and its metabolites reduce the risk of Parkinson’s disease, a progressive neurodegenerative disorder affecting more than 10 million people worldwide.

    The research was part of the EPIC study, a large, prospective cohort that spans six European countries. Researchers looked at how much coffee participants reported drinking and then tracked who developed Parkinson’s. They used statistical models to estimate the risk of developing the disease and analyzed caffeine metabolites in blood samples taken several years before any Parkinson’s diagnosis.

    They found that participants who drank the most coffee had a 37 percent lower risk of developing Parkinson’s than non-coffee drinkers. In addition, higher levels of caffeine and its principal metabolites (paraxanthine and theophylline) were associated with a lower risk of Parkinson’s, even after considering other risk factors, such as smoking and alcohol use.

    These findings suggest that drinking caffeinated coffee protects against Parkinson’s disease. However, coffee is also rich in other bioactive compounds, including polyphenols, alkaloids, and others – many of which exert potent neuroprotective effects.

    While some forms of Parkinson’s disease are genetic, most cases involve a complex interaction between genetic and environmental risk factors. Learn more in this clip featuring Dr. Giselle Petzinger.

  • Tea and coffee provide many health benefits, but for some people, the beverages are often a source of added sugar. A recent study found that adding sugar to tea or coffee increased the risk of premature death by 6 percent; adding sugar to coffee alone increased the risk by 11 percent.

    Researchers tracked the health of more than 2,900 men enrolled in the Copenhagen Male Study over thirty years. The men provided information about their tea and coffee consumption and whether they added sugar to these beverages.

    The researchers found that about a third of the men added sugar to their tea or coffee. Those who did were about 6 percent more likely to die prematurely from any cause than those who didn’t add sugar. Adding sugar to coffee alone increased the risk of dying early by about 11 percent.

    The findings from this large, epidemiological study suggest that adding sugar to tea or coffee increases the risk of dying early, negating some of the longevity benefits often ascribed to the two beverages.

    Sugars are natural components of the human diet, found in fruits, vegetables, and dairy products. However, the refined sugar typically added to beverages like tea or coffee is a highly processed product derived from sugar cane or sugar beets. It undergoes rapid metabolism in the body, causing insulin and blood sugar levels to skyrocket. Nearly 75 percent of adults in the US get about one-tenth of their daily calories from added, refined sugar. Learn more about the effects of sugar on human health in this episode featuring Dr. Rhonda Patrick.

  • Drinking tea and coffee may reduce the risk of developing type 2 diabetes, a 2022 study found. Men that drank a beverage enriched in polyphenols present in tea and coffee had lower blood glucose levels and improved insulin sensitivity than those who drank a placebo.

    Eleven healthy men drank a beverage that contained either polyphenols from tea (catechins) and coffee (chlorogenic acids) or a placebo every day for three weeks. Both beverages provided 119 milligrams of caffeine – a little more than the amount present in one cup of coffee. At the end of the three weeks, they ate a high-fat, high-carbohydrate meal, and then researchers measured their blood glucose, insulin, and other metabolic markers.

    The researchers found that consuming the catechin- and chlorogenic-rich beverage reduced the men’s blood glucose levels when consumed with a high-fat or high-carbohydrate meal. Their insulin sensitivity and levels of hormones involved in glucose metabolism increased, as well.

    Catechins are polyphenolic compounds found in tea, cocoa, and berries. Evidence suggests that catechins ameliorate symptoms associated with diabetes. Chlorogenic acids are polyphenolic compounds found in coffee, apples, and berries. Evidence suggests that chlorogenic acids reduce inflammation, a key player in the pathophysiology of diabetes.

  • Coffee is perhaps best known for its stimulating properties, which arise primarily from its caffeine content. However, coffee is also rich in other bioactive compounds, including polyphenols and alkaloids – many of which exert potent antioxidant, cardioprotective, and neuroprotective effects. Findings from a recent study suggest that coffee reduces the risk of cardiovascular disease and promotes longevity.

    The research involved nearly 450,000 adults (median age, 58 years) who were enrolled in the UK Biobank study. Participants provided information about their daily coffee consumption, including the types (instant, ground, or decaffeinated) and number of cups of coffee consumed, demographics, and overall health. Researchers categorized participants according to coffee intake and tracked them for about 12 years.

    Approximately three-fourths of the participants consumed some coffee each day. Even after considering age, sex, ethnicity, obesity, high blood pressure, diabetes, sleep apnea, smoking status, and tea and alcohol consumption, coffee drinkers were less likely to develop cardiovascular disease or arrhythmias (abnormal heart rhythms) or die prematurely. Drinking 2 to 3 cups of coffee per day provided the greatest protection against premature death and cardiovascular disease; drinking 4 to 5 cups per day provided the greatest protection against arrhythmias.

    These findings suggest that regular consumption of ground coffee reduces the risk of premature death, cardiovascular disease, and arrhythmias, potentially prolonging lifespan. Evidence from other studies suggests that filtered coffee is more protective than unfiltered coffee

  • Drinking two to three cups of coffee a day is linked with a longer lifespan and lower risk of cardiovascular disease compared with avoiding coffee. This was the case for ground, instant and decaffeinated coffee.

    In a study including almost 450,000 adults, drinking 2-3 cups of ground coffee per day was linked to a 27% lower all-cause mortality - in other words dying from all non-accidental causes. 2-3 cups of instant coffee per day was linked to a 11% lower all-cause mortality, and 2-3 cups of decaf coffee per day linked to 14% lower all-cause mortality risk - compared to no daily coffee.

    Drinking 2-3 cups of ground coffee per day was linked to a 20% lower risk of CVD, 2-3 cups of instant coffee per day linked to a 9% lower risk of CVD, 2-3 cups of decaf coffee per day had a 6% lower risk of CVD compared to people that abstain from coffee.

    Caffeine is the most well-known component in coffee, but it contains more than 100 biologically active components - including many polyphenols. The benefits on longevity and lower risks of cardiovascular disease - the number one killer in most developed countries - were found in decaf coffee which does not contain much caffeine.

    But the caffeine had a surprising benefit. Ground and instant coffee, but not decaffeinated, was associated with an up to 17% reduction in arrhythmias including atrial fibrillation compared with non-coffee drinkers.

    While there seems to be mounting evidence that coffee is beneficial - it is important to keep in mind that it shifts the body’s internal clock and if consumed later in the day - may disrupt sleep which could counteract positive benefits.

    These findings suggest that regular consumption of ground coffee reduces the risk of premature death, cardiovascular disease, and arrhythmias, potentially prolonging lifespan. Evidence from other studies suggests that filtered coffee is more protective than unfiltered coffee. Watch Q&A #22 to learn more.

  • Drinking coffee may reduce the risk of stroke in women.

    A stroke occurs when blood flow to the brain is interrupted, killing brain cells. It is the second leading cause of disability and death worldwide, affecting the lives of roughly 102 million people. Evidence suggests that inflammation plays an important role in the pathogenesis of strokes. Findings from a 2011 study suggest that coffee reduces the risk of stroke in women.

    Coffee is one of the most consumed beverages worldwide. It is rich in polyphenolic compounds, including quercetin, chlorogenic acid, and others, that exert beneficial health effects in humans. Evidence suggests that coffee reduces inflammation.

    The study involved nearly 35,000 women enrolled in the Swedish Mammography Cohort. The women, who had no history of cardiovascular disease or cancer at the time of their enrollment, completed questionnaires about their coffee consumption and other lifestyle habits. Using hospital medical records, the investigators gathered information about whether the women experienced a stroke during a 10-year follow-up period.

    They found that drinking coffee was associated with a reduced risk of strokes, even after taking other risk factors into consideration, such as smoking, body mass index, diabetes, hypertension, or alcohol consumption. On average, drinking 1 to 2 cups daily reduced risk by 22 percent; 3 to 4 cups reduced risk by 25 percent; 5 or more cups reduced risk by 23 percent.

    These findings suggest that moderate coffee consumption reduces the risk of stroke in women. Other lifestyle behaviors may reduce stroke risk, too, such as sauna use, which may reduce risk by as much as half. Learn more in this presentation by Dr. Rhonda Patrick.

  • Drinking coffee improves vascular function in people with hypertension.

    Coffee is one of the most consumed beverages worldwide. It is rich in polyphenolic compounds, including quercetin, chlorogenic acid, and others, that exert beneficial health effects in humans. Drinking coffee is linked with reduced disease burden and increased lifespan, possibly due to coffee’s ability to induce autophagy. A recent study suggests that coffee consumption improves vascular function in people with hypertension.

    Hypertension is a chronic elevation of blood pressure that, over time, causes end-organ damage and increases the risk of cardiovascular disease, kidney dysfunction, and death. Key features of hypertension include endothelial dysfunction, an alteration of the vascular endothelium (the thin layer of cells that lines the blood vessels), and vascular smooth muscle dysfunction. Medical professionals typically use flow-mediated dilation to assess endothelial function and nitroglycerine-induced vasodilation to assess vascular smooth muscle function. When combined, the two measures are robust predictors of future cardiovascular events.

    The study involved 462 adults (average age, 65 years) who had hypertension. The investigators assessed the participants' flow-mediated dilation and nitroglycerine-induced vasodilation and collected information about their coffee intake. They assigned the participants to one of two groups: coffee consumers and non-consumers.

    They found that most coffee consumers drank about two cups of coffee per day. Coffee consumers were roughly half as likely to have endothelial dysfunction or vascular smooth muscle dysfunction, compared to non-consumers, even after considering other factors, including age, sex, body mass index, systolic blood pressure, abnormal blood lipids, diabetes, cardiovascular disease, smoking, and systolic blood pressure.

    These findings suggest that moderate coffee intake improves measures of endothelial and vascular health. The authors posited that these benefits may be related to the effects of polyphenolic compounds in coffee, especially chlorogenic acid, a bioactive compound that exerts antioxidant properties, among others.

  • Epidemiological studies have identified links between coffee consumption and a variety of health outcomes. For instance, evidence suggests that drinking five to six cups of coffee a day reduces the risk of developing type 2 diabetes, while drinking three to five cups may reduce the risk of developing Alzheimer’s disease and dementia, compared to drinking none at all. A new study suggests that high caffeinated coffee consumption increases a person’s risk for developing dementia.

    The authors of the study drew on data from more 390,000 people enrolled in the UK Biobank study who were tracked over a period of eight to 12 years. Looking at individuals’ neurological diagnoses, the researchers found that while drinking two to four cups of coffee was associated with lower odds of developing dementia compared to drinking no coffee or exclusively decaffeinated coffee, consuming more than six cups of caffeinated coffee per day markedly increased those odds. The greater risk associated with high coffee consumption was present even when researchers statistically accounted for a variety of demographic factors such as water intake, exercise, sleep quality, stress, and body mass index. The effect also held up equally in men and women, as well as across different age groups.

    Further interesting observations emerged when the researchers examined brain scans of more than 17,500 of the study’s participants. The scans revealed that participants who drank six or more cups per day exhibited the lowest average brain volumes – an effect that was not seen in those who drank decaffeinated coffee, suggesting that the effects were driven by caffeine.

    One of the mechanisms that may drive the harmful effects of caffeine on the brain is caffeine’s blockade of the brain’s adenosine A2 receptors, which have been found to play a crucial role in enabling a subregion of the hippocampus (a structure involved in memory formation) to undergo plasticity and learning. In dampening the A2 receptor signal, caffeine might reduce the formation of new connections and potentially dampen levels of neuronal activity to a point where some connections may be eliminated. Importantly, however, research studies in this field are frequently carried out with young mouse brains, and further research across the entire lifespan is needed.

    These findings demonstrate that high caffeine consumption (defined as drinking more than six cups a day) may contribute to brain shrinkage and have a detrimental impact on neurological function. Caffeine consumption also influences sleep quality, which in turn influences brain health. Learn more about how caffeine affects sleep in this clip featuring Dr. Matthew Walker.

  • Coffee consumption is popular worldwide and is associated with reduced risk of cancer, diabetes, and Parkinson’s disease. However, the American College of Cardiology and American Heart Association recommend avoiding caffeine to reduce the risk of cardiac arrhythmias. Findings from a recent observational report suggest coffee consumption may reduce, not increase, the risk of cardiac arrhythmias.

    Cardiac arrhythmias occur when the electrical impulses that control heart rate pulse too quickly, called tachycardia, or too slowly, called bradycardia. Coffee is the primary source of caffeine for most people. Because caffeine increases serum levels of catecholamines (e.g., adrenaline), it is plausible that coffee may increase the risk of cardiac arrhythmias. Although results from one observational study from 1980 support an increased risk of arrhythmias with increased coffee consumption, newer and more comprehensive evidence is needed.

    The authors collected data regarding habitual coffee consumption and the incidence of cardiac arrhythmias from over 380,000 participants of the United Kingdom Biobank, a long-term registry study of United Kingdom citizens. The researchers assigned participants to one of eight categories of coffee consumption: zero, less than one, one, two, three, four, five, or six or more cups daily. Participants also provided a DNA sample for the sequencing of genes related to coffee metabolism.

    Coffee consumption was associated with a reduced risk of cardiac arrhythmia. For each cup of coffee consumed daily, the risk of arrhythmia was reduced by three percent. This means an individual consuming three cups of coffee would have a nine percent risk reduction. This relationship was significant even after taking age, sex, race, metabolic health, smoking, alcohol and tea consumption, and exercise into account. Participants with genetic variants associated with slower caffeine metabolism drank less coffee, but did not have an increased risk of arrhythmia.

    Greater coffee consumption was associated with a reduced risk of cardiac arrhythmias, a result that contradicts earlier evidence. Learn how coffee consumption may induce autophagy to improve other aspects of health in this clip featuring Dr. Guido Kroemer.

  • Chronic liver disease, which may be caused by hepatitis infection, alcohol misuse, or non-alcoholic fatty liver disease, is a major public health concern worldwide. Previous epidemiological research has reported a link between coffee consumption and decreased risk of liver cancer and fatty liver disease. A new report describes the relationship between different types of coffee and liver disease risk.

    Coffee contains a number of bioactive plant compounds including chlorogenic acid, cafestol, and kahweol, which have anti-inflammatory and anti-cancer effects. Coffees vary widely in their preparation including decaffeination, roasting duration, brewing temperature, and filtering. Decaffeinated and filtered coffees may have fewer bioactive compounds, but how these and other processing characteristics impact chronic liver disease risk reductions is unclear.

    The authors collected data regarding coffee consumption from almost 500,000 participants in the United Kingdom Biobank, a long-term registry study of United Kingdom citizens. Participants completed surveys asking about the amount and type of coffee (decaffeinated, instant, ground, or other) they consumed. The researchers used medical and death records to assess disease presence. The average length of time that participants were followed for the study was 10 years.

    Most participants (about 78 percent) consumed coffee, and the average amount of coffee consumed daily was two cups. Compared to non-coffee drinkers, coffee drinkers had a 21 percent lower risk of developing chronic liver disease and a 49 percent lower risk of dying from chronic liver disease. Coffee type did not have an effect on disease risk, with instant and decaffeinated coffee producing similar risk reductions compared with normal ground coffee.

    The authors concluded that the consumption of coffee, regardless of preparation, is protective against chronic liver diseases. They suggested that future research should investigate the effects of a coffee intervention in treating liver disease.

  • Consuming caffeinated beverages such as tea and coffee is a common practice in many cultures around the world. While tea and coffee contain beneficial plant compounds such as antioxidants that lower the risk of disease, the caffeine in tea and coffee increases blood pressure, which may contribute to hypertension-related diseases such as chronic kidney disease, stroke, and glaucoma. Findings of a recent report detail the relationship between caffeine consumption and glaucoma risk.

    In glaucoma, the pressure of fluid inside the eye (called intraocular pressure) increases, damaging the optic nerve at the back of the eye. Over time, as damage to the optic nerve accumulates, the risk of vision loss increases. While previous research investigating acute caffeine intake has demonstrated an increase in intraocular pressure following caffeine conumption, research on chronic caffeine consumption has found no relationship between caffeine intake and glaucoma risk. The risk of habitual caffeine consumption may depend on genetics, as other research has found a positive relationship between habitual caffeine intake and glaucoma in those with genetic susceptibility.

    The authors conducted a genome-wide association study, a type of study in which researchers look for associations between gene variations called single-nucleotide polymorphisms and disease prevalence. The authors collected genetic data, clinical data measuring intraocular eye pressure, and self-reported dietary data regarding coffee and tea consumption from more than 100,000 participants enrolled in the United Kingdom Biobank study. Next, the authors calculated each participant’s polygenic risk score, which estimates an individual’s genetic susceptibility to a specific disease. Finally, the authors performed a Mendelian randomization analysis, which measures variation in specific genes in order to examine the cause and effect relationship between environmental factors (coffee consumption and total caffeine intake) and disease (glaucoma) risk.

    The data revealed that greater total caffeine intake was associated with lower intraocular pressure, but the relationship was not statistically significant. Participants consuming the most caffeine (232 milligrams of caffeine per day or more, the amount in 20 ounces of coffee) had a reduction in intraocular pressure of 0.10 millimeters of mercury (the unit used for blood and eye pressure) compared to participants with the lowest caffeine intake (less than 87 milligrams per day, the amount in one 8-ounce cup of coffee).

    Among participants with a high polygenic risk score for glaucoma, however, consuming greater amounts of caffeine (more than 480 milligrams per day, the amount in 42 ounces of coffee) was significantly associated with an increase in intraocular pressure of 0.35 millimeters of mercury compared to participants consuming the least caffeine (less than 80 milligrams per day, the amount in 7 ounces of coffee). While the authors found no overall relationship between caffeine intake and glaucoma, participants with high polygenic risk scores consuming 321 milligrams of caffeine per day or more were four times more likely to develop glaucoma.

    The authors concluded that they found no relationship between caffeine consumption and glaucoma risk in the general population. However, their analyses revealed a significant relationship between higher caffeine consumption and increased risk of high intraocular pressure and glaucoma incidence in those with the highest genetic susceptibility for the disease.

  • DNA damage occurs with normal metabolism and upon exposure to toxic environmental factors. It is associated with the development of some cancers, cardiovascular diseases, diabetes, and inflammatory bowel diseases. Coffee contains a number of compounds with antioxidant properties, and previous research has shown that coffee and coffee extracts may reduce DNA damage in colon cells and white blood cells. Findings of this randomized controlled trial detail the effects of daily coffee consumption on DNA damage in healthy adults.

    Coffee constituents such as caffeic acid, catechol, hydroxyhydroquinone, trigonelline, and alkylpyridinium compounds enhance cellular protection by activating Nrf2, a transcription factor that regulates the expression of antioxidant proteins like glutathione. Of these constituents, the alkylpyridinium compounds, which are produced during roasting, were the most robust activators of Nrf2. One study comparing dark and medium roast coffee blends found that both blends reduced DNA damage; however, this study did not include a control group.

    The researchers recruited 100 healthy adults to participate in their study and randomly assigned them to one of two groups that were matched for weight and age. During a preconditioning period, they asked participants to consume at least 16 ounces of water per day and to avoid coffee, tea, and other caffeine-containing beverages and foods for four weeks. During the intervention period, participants in one group consumed 16 ounces of freshly brewed dark roast coffee blend per day for four weeks while the other group continued to drink water and avoid coffee. Participants gave blood samples at baseline and at the end of each four-week period for the measurement of DNA damage, using a test called the comet assay, which measures DNA strand breaks.

    DNA damage did not change between the preconditioning and intervention period for participants in the water group, while participants in the coffee group had a reduction in DNA damage. Compared to their baseline intake of coffee and other antioxidant-rich foods and beverages, participants who consumed the study coffee treatment had a significant 23 percent reduction in DNA damage levels. These effects were similar between males and females.

    The authors concluded that regular consumption of dark roast coffee reduces DNA damage in healthy adults compared to water consumption. They advise that future studies should compare the effects of different kinds of coffee (e.g., light, medium, and dark roast) on DNA damage and health.

  • Coffee contains a wide range of bioactive compounds that influence human health. Evidence suggests that coffee consumption reduces the risk of cardiovascular disease-related deaths and certain types of cancer. Findings from a new study suggest that caffeine in coffee improves fat metabolism when consumed prior to exercise.

    Caffeine is an alkaloid compound with potent stimulatory effects. Evidence indicates it improves performance in both endurance and resistance exercise. Some of these effects may be due to caffeine’s capacity to decrease the perception of effort and increase the neural actions on muscle fibers.

    The triple-blind, placebo-controlled, crossover trial involved 15 healthy men (average age, 32 years) who were endurance trained but not regular consumers of caffeine. The men cycled on a stationary bike while slightly increasing the resistance every minute until they reached exhaustion. The test was performed four times, either in the morning (8 a.m.) or afternoon (5 p.m.), with each test separated by seven days. Thirty minutes prior to exercising, the men ingested either anhydrous caffeine powder from green coffee beans (3 milligrams per kilogram of bodyweight) or a placebo. The authors of the study monitored the men’s heart rate, maximal fat oxidation (and the exercise intensity at which it occurs), and respiratory function (VO2 max) during the exercise test.

    They found that maximal fat oxidation and the intensity at which it occurs exhibited a diurnal pattern, with higher values seen when the men exercised in the afternoon rather than in the morning. Caffeine potentiated the diurnal effect, increasing the men’s average maximum fat oxidation by nearly 11 percent in the morning and 29 percent in the afternoon. Caffeine also increased the exercise intensity at which the fat oxidation occurred by 11 percent in the morning and by 13 percent in the afternoon.

    These findings suggest that caffeine improves fat oxidation in endurance athletes and these effects are influenced by a diurnal rhythm. Consuming caffeine in the morning maximized fat oxidation to a degree similar to that seen without caffeine in the afternoon. It is important to note that while caffeine intake may improve fat oxidation, intake late in the day can impair sleep, potentially negating some of the beneficial effects of exercise. Learn more about the effects of caffeine on sleep in this clip featuring sleep expert Dr. Matthew Walker.

  • Colorectal cancer, the third most common cancer among men and women living in the United States, will likely claim the lives of more than 50,000 people this year. The cancer often metastasizes, or spreads, to other sites, particularly the lungs, liver, or brain, decreasing a person’s chances of survival from the disease. Findings from a new study suggest that drinking coffee reduces the risk of colorectal cancer metastasis.

    Coffee contains a multitude of polyphenolic compounds that appear to exert beneficial health effects, including quercetin, chlorogenic acid, and others. Drinking coffee is linked with reduced disease burden and increased lifespan, possibly due to coffee’s ability to induce autophagy. Other evidence suggests that coffee’s beneficial effects arise from its antioxidant and anti-inflammatory effects as well as its capacity to maintain healthy blood insulin levels – a critical aspect in colorectal cancer outcomes.

    The prospective observational cohort study involved more than 1,100 people with colorectal cancer who were enrolled in a larger randomized clinical trial investigating the efficacy of chemotherapy drugs. The study participants, who were between the ages of 51 and 67 years, provided information about what they ate and drank using a food frequency questionnaire.

    Over a period of approximately five years, 93 percent of the participants experienced disease progression, or they died. Participants who drank coffee were less likely to die than those who did not, and this association was dose dependent. For example, those who drank two to three cups per day were 18 percent less likely to die, and those who drank four cups per day were 36 percent less likely to die. These associations held true regardless of whether they drank caffeinated or decaffeinated coffee.

    These findings suggest that drinking coffee reduces the risk of disease progression and death in people with advanced or metastatic colorectal cancer. A key player in suppression of tumor growth is autophagy, a biological process that inhibits cancer-cell survival and induces cell death. Learn more about how coffee induces autophagy in this clip featuring autophagy expert, Dr. Guido Kroemer.

  • Diet-induced insulin resistance caused blood vessels to become leaky which impaired blood and oxygen flow to a brain region involved in learning and memory (animal evidence).

    Obesity and insulin resistance are associated with a leaky blood-brain barrier. This new animal study found that a high-sugar combined with a high-fat diet caused shrinkage of the tight junctions between endothelial cells that make up the blood-brain barrier and actual holes in those cells.

    Obesity is known to increase toll-like receptor activation through a variety of mechanisms. One of the mechanisms is through through associated increases of circulating of lipopolysaccharide. Another mechanism is the leaking of fatty acids from fatty acids, triggering toll-like receptors through the recognition of damage-associated molecular patterns (DAMPs). (See “obesity” section of toll-like receptor article.)

    Furthermore, LPS challenge in animal studies induces microglia in the brain to attack and damage the blood-brain barrier.

    Blocking adenosine may play a role in preventing impairment of the blood-brain barrier by diet-induced obesity

    However, adenosine, which helps us sleep and helps regulate our blood pressure and is blocked by caffeine may play a role in preventing some of the damaging effects obesity has on the blood-brain barrier, which promotes dementia.

    From the article:

    They knew that chronic activation of the receptor Adora2a [an adenosine receptor] on the endothelial cells that line this important barrier in our brain can let factors from the blood enter the brain and affect the function of our neurons.

    Now Medical College of Georgia scientists have shown that when they block Adora2a in a model of diet-induced obesity, this important barrier function is maintained.

    […]

    In the brain, adenosine is a neurotransmitter that helps us sleep and helps regulate our blood pressure; in the body it’s also a component of the cell fuel adenosine triphosphate, or ATP. Adenosine also activates receptors Adora1a and Adora2a on endothelial cells, which normally supports healthy relationships between brain activity and blood flow.

    Problems arise with chronic activation, particularly in the brain, which is what happens with obesity, says Stranahan.

    People who have obesity and diabetes have higher rates of cognitive impairment as they age and most of the related structural changes are in the hippocampus, a center of learning and memory and Stranahan’s focus of study. Fat is a source of inflammation and there is evidence that reducing chronic inflammation in the brain helps prevent obesity-related memory loss.