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You’re going to love this issue of the Science Digest. We’ve got some really interesting stories about the latest research related to nutrition, fitness, and health. Read on to learn how…
Drinking dark roast coffee decreases DNA damage in healthy adults.
Spending time in nature improves brain health.
Eating mushrooms reduces the risk of cognitive impairment in older adults without dementia.
And much more!
In other news…
We’ve got another Crowdcast live Q&A coming up Saturday, June 7, at 9:30 am PDT. The code for this event is quercetin. Remember, you can always access the most recent event code and Q&A calendar on the member’s dashboard.
Catch ya later!
Rhonda and team
Science Digest – May 21, 2021
Drinking dark roast coffee reduces DNA damage in healthy adults.
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 a 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, are the most robust activators of Nrf2. One study comparing dark and medium roast coffee blends found that both blends reduced DNA damage, but the study did not include a control group.
The researchers involved in the present study recruited 100 healthy adults to participate 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.
The researchers found that DNA damage decreased between the preconditioning and intervention period among those who drank coffee. They noted no changes in DNA damage among those who drank water. 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 advised that future studies should compare the effects of different kinds of coffee (e.g., light, medium, and dark roast) on DNA damage and health.
Link to full report.
Learn more about the benefits of coffee on healthspan in this clip featuring Dr. Guido Kroemer.
Spending time in nature improves brain health.
Roughly half of the world’s population lives in urban areas, far removed from the natural environment. Evidence indicates that people who live in urban areas are at greater risk for mental health disorders, such as depression. Findings from a new study suggest that walking in nature reduces ruminative thinking and decreases activity in parts of the brain associated with mental illness.
Ruminative thinking – dwelling on ideas (especially stressors) to excess – is a common feature of mental illness. Rumination can set in motion a cascade of hormonal and physiological responses that harm mental and physical health. A major player in the body’s response to rumination is a biological pathway that starts in the brain’s hypothalamus with the release of corticotrophin-releasing hormone, which drives the stress hormone system and has a direct effect on many parts of the body, including the brain, gut, and DNA.
Spending time in nature is associated with a variety of beneficial effects on mental and physical health. For example, some research indicates that walking in forested areas, a practice sometimes referred to as “forest bathing,” improves immune function, likely due to beneficial bioactive compounds produced by trees and inhaled by walkers. Other research has identified dose-dependent improvements in health following natural experiences.
The study involved 38 mentally healthy men and women living in a large urban area. Half of the participants took a 90-minute walk in a natural area where native plants, animals, and birds were in abundance. The other half took a 90-minute walk in an urban area where there were busy streets and heavy traffic. To rule out any physiological effects of exercise on brain health and function, both groups wore monitors to measure their heart rate and respirations. After their respective walks, participants underwent magnetic resonance imaging (MRI) studies of their brains, with emphasis on the subgenual prefrontal cortex, an area of the brain involved in emotional regulation and reward mechanisms. Before and after the walks, they completed a questionnaire in which they rated their ruminative tendencies.
The monitors revealed that the walks were equal in distance and exerted no physiological effects on the walkers. The MRI studies indicated that after the participants walked in a natural area, their subgenual prefrontal cortex showed less activity. Those who walked in the urban area showed no changes in this region of the brain. Participants who walked in the natural area reported less ruminative thinking after the walk, but those who walked in the urban area did not.
These findings suggest that spending time in the natural environment benefits brain health and reduces ruminative thinking, underscoring the importance of public health measures to increase natural spaces within urban areas. If natural areas are not easily accessible, meditation offers another means of reducing ruminative thinking. Learn more about the benefits of meditation in this episode featuring Dr. Rhonda Patrick.
Link to full study.
Eating mushrooms reduces the risk of cognitive impairment in older adults without dementia.
Mild cognitive impairment is an intermediary stage between normal cognitive functioning and dementia and may be treatable with diet and lifestyle interventions. Mushrooms contain a number of bioactive compounds, such as hericenones and erinacines, that increase nerve growth factor production and ergothione, an antioxidant and cellular protective compound. One group of researchers examined the relationship between mushroom consumption and mild cognitive impairment in older adults.
A large population-based study demonstrated that mushroom intake improved cognitive performance among Norwegian participants (ages 70 to 74 years). A study in Japanese participants (ages 65 years and older) found that eating mushrooms three times per week or more reduced the risk of dementia by 19 percent. However, the effect of mushroom consumption on the risk of mild cognitive impairment is unknown.
The authors reviewed data from over 600 participants without dementia (ages 60 years and older) from a study in Singapore focused on identifying dietary factors associated with healthy aging. Participants provided data regarding demographics, lifestyle, diet, health history, cognitive function, and psychological well being, among others. The researchers interviewed participants to assess their mushroom intake and measured participants’ cognitive function using a standardized questionnaire.
Participants who consumed more than two servings of mushrooms per week (1.5 cups of cooked mushrooms, about 300 grams) were 43 percent less likely to have mild cognitive impairment than those who consumed mushrooms less than once per week. This association was independent of age, sex, education, cigarette smoking, alcohol consumption, hypertension, diabetes, heart disease, stroke, physical activities, and social activities. Participants with mild cognitive impairment were more likely to have hypertension and diabetes and were less active in social activities.
The results of this cross-sectional study support the potential of mushroom consumption in delaying the development of cognitive decline. The authors noted that a strength of their study was their accounting of lifestyle and health factors.
Link to full report.
Spermidine supplementation improves memory performance in older adults.
Spermidine is a polyamine compound that may increase healthspan due to its ability to induce autophagy, the process by which the body removes damaged and dysfunctional cells. In animal models, spermidine supplementation has been shown to prevent memory loss. Findings from a recent report detail the first experiment exploring the effects of spermidine supplementation on memory in older adults without dementia.
Episodic memory, which records specific events, situations, and experiences, declines with age, but this loss may be impeded by certain lifestyle interventions, such as caloric restriction. The effects of spermidine in the body mimic caloric restriction, making it a promising therapy for the reversal of memory loss. Previous research demonstrates the ability of spermidine supplementation to restore memory performance in fruit flies, but the effects of spermidine supplementation on memory performance in humans are unknown.
The authors recruited 30 adults (aged 60 to 80 years) with subjective cognitive decline (self-reported worsening of confusion or memory loss), a condition associated with objective cognitive decline and Alzheimer’s disease. They assigned half of the participants to consume a capsule containing 750 milligrams of a spermidine-rich plant extract containing 1.2 milligrams of spermidine daily for three months, while the other half consumed a placebo supplement. Participants completed memory assessments and other cognitive testing before and after the supplement period.
Participants consuming the spermidine supplement had moderately enhanced memory performance after three months compared to those who took the placebo. In particular, spermidine supplementation enhanced mnemonic discrimination, the ability to differentiate between new and previously encountered items. There was no difference in other cognitive functions between groups.
The authors concluded that spermidine supplementation may be an effective treatment for slowing cognitive decline in older adults with subjective cognitive impairment. They noted that this was a small pilot trial and that larger clinical trials are needed to expand on these results.
Link to full report.
Drinking fructose-containing beverages may increase risk for metabolic disease.
Metabolic diseases, such as type 2 diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD), represent a major public health burden. Dietary factors such as excess sugar intake are associated with greater metabolic disease risk; however, it is unclear how different types of sugars (e.g., glucose, fructose, or sucrose) differentially impact metabolic health. Researchers recently investigated the effects of sugar-sweetened beverages on fatty acid synthesis, blood triglycerides, and hepatic (liver) insulin resistance in healthy males.
Glucose promotes pancreatic release of insulin into the bloodstream so that insulin-sensitive organs such as the liver, skeletal muscle, and adipose tissue can transport the glucose into their cells. Excess glucose (not required for immediate use) is converted to fat in the liver via a process called de novo lipogenesis and then stored in adipose tissue. As fat levels in adipose tissue rise (i.e., overweight and obesity), fat accumulates in the liver, leading to the development of NAFLD. Fructose, the main sweetener found in sugar-sweetened beverages, does not require insulin to be absorbed. It is preferentially taken up by the liver, accelerating NAFLD development, independent of weight gain.
The authors recruited 94 healthy lean males (average age, 23 years) and assigned them to consume beverages sweetened with moderate amounts of either glucose, fructose, or sucrose (a sugar that contains both glucose and fructose) in addition to their normal diet for seven weeks. The beverages contained an amount of sugar found in about two cans of non-diet soda. The researchers assigned a fourth group of participants to consume their normal diet with no added sugar-sweetened beverages. They assessed fatty acid and triglyceride synthesis by the liver and whole-body fat metabolism.
Daily consumption of beverages sweetened with fructose and sucrose, but not glucose, led to a twofold increase in fat production in the liver. Fructose intake did not increase triglyceride production in the liver or whole-body fat metabolism. Participants from all four groups consumed about the same amount of calories, and while body weight tended to increase for all groups, this relationship was only statistically significant for the group consuming glucose-sweetened beverages. Glucose and insulin tolerance did not change with sugar-sweetened beverage consumption.
The investigators concluded that consumption of beverages sweetened with fructose and sucrose increased fat production in the liver. While they did not observe changes in other metabolic markers such as insulin tolerance, they hypothesized that the alterations in fat production by the liver pave the way for metabolic disease.
Link to full report.
Learn about the effects of sugar-sweetened beverages on aging in this episode featuring Dr. Elissa Epel.
Added dietary sugars have harmful effects on health and behavior in mice at human-relevant doses.
Sugar consumption in the United States has increased approximately 50 percent since the 1970s, partly due to the use of high fructose corn syrup, which is often added to beverages and other processed foods. Consumption of added dietary sugars is associated with increased risk for metabolic diseases, such as obesity, type 2 diabetes, cardiovascular disease, and fatty liver disease. The mechanisms that drive these diseases have been explored in research using mouse models, but the dose of sugar used in these studies is usually much larger than what is normally consumed by people. Authors of this report investigated the effects of human-relevant doses of added sugars on health and behavior in mice.
Mouse models are a useful tool in research because mice can be kept in environments where their exposure to light, food, socialization, and other inputs is completely controlled, minimizing variation between mice exposed to a dietary intervention. However, these highly controlled environments, combined with large doses of experimental foods, often limit the generalizability of mouse research for human health. Organismal performance assays, which use seminatural conditions to put experimental animals in direct competition with each other, more accurately measure survival, competitive ability, and reproduction (common measures of evolutionary fitness) in response to environmental exposures.
The investigators fed one group of mice a diet containing 25 percent of calories from a 1:1 mixture of fructose and glucose, the same ratio of sugars found in beverages and processed foods containing high fructose corn syrup. They fed a second group of mice a control diet in which the added sugars were replaced with cornstarch and fiber. Both groups of mice consumed their respective diets and lived in controlled environments for 26 weeks before entering the organismal performance assay, upon which all mice consumed the high-sugar diet. The researchers observed mice as they competed for territory, resources, and mates for 26 to 32 weeks.
Female mice fed a high sugar diet prior to entering the organismal performance assay were twice as likely to die than female mice fed a normal diet. Male mice fed a high sugar diet controlled 26 percent less territory and produced 25 percent fewer offspring compared to mice fed a normal diet prior to entering the organismal performance assay. A high-sugar diet increased fasting cholesterol levels and decreased glucose tolerance in the mice.
The authors concluded that a high sugar diet decreased survival, competitive ability, and reproduction in mice and led to metabolic dysfunction. This study was the first to use organismal performance assays in combination with an environmental intervention and the first to demonstrate the negative health effects of added sugars in mice at human-relevant doses.
Link to full report.
Learn about the effects of refined sugar on health in this episode featuring Dr. Rhonda Patrick.
Omega-3 supplementation improves cognitive performance in cognitively healthy older adults with coronary artery disease.
Dementia is a large and growing health concern facing older adults, with approximately 15 to 20 percent of people aged 65 years and older living with mild cognitive impairment. Omega-3 fatty acids have benefits for those with mild cognitive impairment who also have coronary artery disease, a risk factor for dementia because it restricts blood flow to the brain. Findings of a recent report demonstrate the effects of omega-3 supplementation on cognitive decline in cognitively healthy older adults with coronary artery disease.
The omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) protect the aging brain by decreasing oxidative stress and inflammation and increasing neurogenesis. Consuming omega-3 rich foods such as fish is associated with a decreased risk of Alzheimer’s disease, while low blood levels of DHA are associated with smaller brain volume, a hallmark of cognitive decline. Few studies have measured the impact of long-term omega-3 supplementation on cognitive function in adults without cognitive impairment or dementia.
The researchers enrolled 285 adults (average age, 63 years) who had stable coronary artery disease and were taking cholesterol-lowering statin medication. They assigned half of the participants to consume an EPA and DHA supplement (approximately 3 grams of omega-3 fatty acids total) for 30 months while the other half consumed no supplement. Participants completed a battery of cognitive tests at baseline, 12 months, and 30 months, measuring global cognition, language, verbal fluency, visual-motor coordination, psychomotor speed, and memory.
After 30 months of omega-3 supplementation, participants had significantly better scores for verbal fluency, language, and memory than participants who did not supplement. Participants who supplemented also performed better on two measures of visual-motor coordination. These improvements were measurable at just 12 months of supplementation.
The investigators concluded that combined EPA and DHA supplementation improved cognition in cognitively healthy older adults with coronary artery disease. These results demonstrate the ability of omega-3 fatty acids to protect brain health even in those with coronary artery disease, a risk factor for dementia.
Link to full report.
Learn more about the neuroprotective effects of DHA from krill oil in this episode featuring Dr. Rhonda Patrick.
Daily apple consumption decreases multiple markers of obesity-associated inflammation.
Obesity is characterized by chronic low-grade inflammation, which contributes to the development of cardiovascular disease. While consumption of processed foods and beverages high in saturated fats and simple sugars is associated with a higher risk of cardiovascular disease, consumption of plant-based foods, including fruits, is associated with a lower risk. A recent report describes the effects of daily apple consumption on inflammation, endotoxemia, and metabolism.
One of the causes of obesity-associated inflammation is leaky gut, a condition where the intestinal barrier is compromised, leading to increased levels of bacterial endotoxins (toxins that are released when bacteria die) in the bloodstream, a condition called endotoxemia. This increase in endotoxin levels activates white blood cells to secrete pro-inflammatory cytokines such as interleukin (IL)-6 and IL-17. Plant-based foods such as apples are beneficial for people with obesity because they are rich in bioactive compounds that decrease inflammation and dietary fibers that strengthen the gut barrier.
The researchers recruited 46 participants with overweight and obesity and directed them to avoid foods and beverages rich in polyphenols and/or dietary fibers (e.g., coffee, vegetables, grains, beans, and red/purple/blue fruits) for two weeks. Next, they assigned half of the participants to consume three Gala apples per day for six weeks or to avoid apples. Both groups continued to eat a diet with limited polyphenols and dietary fibers. Participants provided blood samples for the collection of white blood cells and measurement of pro-inflammatory cytokines. After isolating the white blood cells, the researchers stimulated them with endotoxin and measured their response.
Apple consumption decreased plasma C-reactive protein (a pro-inflammatory cytokine) by 17 percent, IL-6 by 12 percent, and endotoxin-binding protein by 20 percent compared with no apple consumption. White blood cells from participants who consumed apples secreted 28 percent less IL-6 and 11 percent less IL-17. While apple consumption increased total antioxidant capacity in blood by 10 percent, it had no effect on cardiovascular disease markers.
These findings suggest that six weeks of daily Gala apple consumption helped mitigate inflammation in those consuming a diet low in polyphenols and fiber, a common feature of the Western dietary pattern. Apple consumption may decrease cardiovascular disease risk in those with obesity, even without weight loss.
Link to full report.
COVID-19 vaccines are effective against variants of concern.
In recent months, several variants of SARS-CoV-2, the virus that causes COVID-19, have emerged. The most notable of these are B.1.1.7, first identified in the United Kingdom; B.1.351, first identified in South Africa; and P.1, first identified in Brazil. To be considered a variant, a virus must have sufficient mutations to change a portion of its genetic code. The B.1.1.7 variant has 17 mutations, the B.1.351 variant has 10 mutations, and the P.1 variant has three mutations. Findings from three recent studies indicate that vaccines and boosters using mRNA technology or recombinant technology are effective against the variants.
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 spike protein located on the SARS-CoV-2 surface. The use of mRNA vaccine technology allows rapid scaling of vaccine production and facilitates modification if the virus mutates significantly. Two mRNA vaccines (Pfizer-BioNTech and Moderna) are currently authorized for use in the United States.
Recombinant vaccine technology inserts the genetic information (DNA) for the spike protein into insect cells, where it is replicated. The DNA is then harvested, purified, and housed in nanoparticles. The Novavax recombinant vaccine has been tested in trials in the United States, United Kingdom, Mexico, and South Africa.
The first of the studies assessed effectiveness of the Pfizer-BioNTech vaccine against the B.1.1.7 variant. The study was conducted in Israel, where 95 percent of all COVID-19 cases were caused by the B.1.1.7 variant. The authors of the study found that two doses of Pfizer-BioNTech vaccine were 97 percent effective against COVID-19 (including those caused by the B.1.1.7 variant) in vaccine recipients aged 16 to 85 years.
The second study was a phase 2 trial that assessed three candidate mRNA vaccines from Moderna: a booster against B.1.351; a combination booster containing a 50-50 mix of the original vaccine and the B.1.351 vaccine; and a booster containing a lower dose of the original vaccine. Vaccination with the B.1.351 booster or the 50-50 mix of the B.1.351 vaccine and the original vaccine increased antibody titers against both the B.1.351 and P.1 variants.
A third study looked at the effectiveness of the Novavax vaccine against the B.1.351 variant among people living in South Africa, where the variant first emerged. The vaccine was tested among HIV-negative and HIV-positive participants. It was 60 percent effective against mild, moderate, and severe COVID-19 illness in HIV-negative participants and 50 percent effective in HIV-positive participants.
These findings indicate that three commonly used vaccines are highly effective against emerging SARS-CoV-2 variants in adults. Ongoing and future trials will assess their efficacy and safety in other populations.
Link to Pfizer study.
Link to Moderna press release.
Link to Novavax study.
Drinking sugar-sweetened beverages increases the risk of early-onset colorectal cancer among young women.
Colorectal cancer cases and death rates in the United States have been declining since the 1980s, likely due to increased awareness and screening, which typically begins at age 50. However, the number of colorectal cancer cases in young adults – those between the ages of 20 and 49 years – is increasing. Findings from a recent study suggest that consumption of sugar-sweetened beverages increases the risk of early-onset colorectal cancer among young women.
Dietary factors play critical roles in colorectal cancer risk. Consumption of plant-based foods have been shown to decrease colorectal cancer risk. For example, ellagic acid, a bioactive compound present in walnuts and pomegranates, breaks down in the gut to yield urolithins, a class of compounds that exert anti-inflammatory and anti-cancer effects. Conversely, evidence suggests that consumption of red meat increases colorectal cancer risk by 20 to 30 percent.
The participants in the present study included approximately 95,000 women who were part of the Nurses Health Study II, a prospective cohort study of female nurses living in the United States between 1991 and 2015. At the time of their enrollment, the nurses were 25 to 42 years old and cancer-free. Every two years, the women provided information about their demographics, lifestyles, and overall health, including whether they had been diagnosed with colorectal cancer. Every four years, they completed food frequency questionnaires that included questions about their dietary patterns. A subset of approximately 41,000 women provided information about their beverage intake during their teen years.
The authors of study found that 109 of the women in the study group developed early onset colorectal cancer. Women who drank two or more servings of sugar-sweetened beverages per day during adulthood were more than twice as likely to develop early onset colorectal cancer than women who consumed less than one serving per week. This risk was dose-dependent, with a 16 percent higher risk per daily beverage increase. If the women drank sugar-sweetened beverages during their teen years, their risk increased 32 percent for each serving per day increase. Replacing sugar-sweetened beverages with artificially sweetened beverages or milk decreased their risk of early onset colorectal cancer by 17 to 36 percent.
These findings suggest that consuming sugar-sweetened beverages during adolescence and adulthood markedly increases a woman’s risk of developing colorectal cancer. Dietary modifications that include consumption of artificially sweetened beverages or milk appear to reduce risk.
Link to study abstract.