Hello, friends!
We’ve lined up some great stories for this issue of the Science Digest, your go-to source for the latest scientific research about nutrition, health, and lifestyle. In this issue, you’ll read how…
Vitamin D supplementation improves cognitive function and lengthens telomeres in people with mild cognitive impairment.
Vitamin D supplementation may help patients clear the SARS-CoV-2 virus.
Melatonin use may reduce risk for COVID-19.
And much more!
In other news:
We’ve got another Crowdcast live Q&A coming up in one hour. The code for this event: fasting. Remember, you can always access the most recent event code and Q&A calendar by visiting your dashboard at foundmyfitness.com/dashboard
And ICYMI: We just finished up a themed month of all-things-sulforaphane, so be sure to check out our Q&A with sulforaphane expert Dr. Jed Fahey, our illustrated how-to guide to sprouting (a great way to obtain sulforaphane), this short companion video showing the sprouting process, a ton of awesome new clips, including this one featuring Dr. Fahey’s remarks regarding the Joe Rogan podcast about sulforaphane being a goitrogen.
Enjoy!
Rhonda and team
Science News Digest – December 5, 2020
Vitamin D supplementation improves cognitive function and lengthens telomeres in people with mild cognitive impairment.
Some scientists have proposed that mild cognitive impairment is a transitional stage before the development of Alzheimer’s disease, one of the most common causes of dementia. Epidemiological evidence suggests that vitamin supplementation may support cognitive function. New research demonstrates reduced oxidative stress and improved cognition after 12 months of vitamin D supplementation in people with mild cognitive impairment.
Current evidence suggests that lifestyle factors like diet and exercise influence the progression of cognitive decline by increasing or decreasing oxidative stress that damages the brain. Previous studies have demonstrated the association between telomere length, a marker of DNA integrity, and mild cognitive impairment or Alzheimer’s disease progression. Vitamin D supplementation has been shown to improve working memory; however, the mechanisms that drive these improvements are unknown.
The randomized placebo-controlled study involved 183 participants who had mild cognitive impairment. Approximately half of the participants took 800 international units of vitamin D daily for one year, and the remainder took a placebo. The authors of the study assessed the participants’ cognitive function and measured key biomarkers, including telomere length and markers of oxidative stress.
Participants who took the vitamin D supplement performed significantly better on tests of cognitive function. Supplementation also increased the participants’ telomere length and decreased markers of oxidative stress in their blood.
The authors believe their findings are consistent with previous studies demonstrating the protective effects of vitamin D in the brain. The optimal dose of vitamin D is unknown and likely varies between individuals, limiting the ability to interpret these results. The authors also noted that blood markers of oxidative stress may not be a reliable measure of the brain environment. Future studies should include more participants and a longer length of supplementation.
Link to full study.
Vitamin D supplementation may help patients clear the SARS-CoV-2 virus.
COVID-19 is a respiratory infection caused by the SARS-CoV-2 virus. A growing number of studies have demonstrated the importance of vitamin D in regulating the immune system and controlling COVID-19 disease severity. Authors of a new study found that vitamin D supplementation shortened SARS-CoV-2 infection in vitamin D-deficient people.
Vitamin D is a hormone that affects the expression of many genes important for immune function. Vitamin D deficiency is associated with greater risk of influenza and other respiratory infections. Unfortunately, one 2012 report estimates that approximately half of all people worldwide have vitamin D insufficiency, and 1 billion have vitamin D deficiency, defined as blood levels less than 12 nanograms per milliliter.
The study involved 40 adults who had a positive SARS-CoV-2 RNA test; mild or no COVID-19 symptoms; and vitamin D deficiency (blood level less than 20 nanograms per milliliter). The authors assigned 16 study participants to take 60,000 international units of vitamin D3 (cholecalciferol) orally until they reached a blood level greater than 50 nanograms per milliliter.
At baseline, the average serum vitamin D level in the treatment group was 8.6 nanograms per milliliter. After two weeks of supplementation, 75 percent of the participants achieved a vitamin D blood level greater than 50 nanograms per milliliter. Those who corrected their deficiency were more likely to clear the virus by day 21 of the study. They also experienced a decrease in serum fibrinogen, a marker of inflammation.
The authors concluded that short-term high dose oral vitamin D supplementation is effective in correcting deficiency and promotes the clearance of SARS-CoV-2. They encouraged cholecalciferol supplementation as a way to decrease viral transmission.
Link to full study.
Learn more about how vitamin D supplementation may reduce susceptibility to COVID-19-associated lung injury in this clip from a Q&A with Dr. Rhonda Patrick.
Melatonin may reduce risk of COVID-19.
SARS-CoV-2 is the virus responsible for COVID-19. As SARS-CoV-2 infection rates climb, scientists continue to search for drugs that could be repurposed for COVID-19 treatment. Authors of a new multiomics study report that melatonin use dramatically reduced the likelihood of SARS-CoV-2 infection, especially for African Americans.
Multiomics is an approach to data analysis that incorporates multiple levels of cellular biology, including the genome (DNA), transcriptome (RNA), and proteome (protein). The network of interactions between these multiple “omes,” a virus, and its host is referred to as the interactome.
The authors built multiomic data sets from several previous studies in humans, animals, and cell lines to investigate the SARS-CoV-2-host interactome. Based on these data sets, the authors identified 34 drugs that could be repurposed for COVID-19. Next, they reviewed the medical records of more than 18,000 participants for use of those drugs and presence of SARS-CoV-2 infection.
They found that melatonin usage was associated with a 28 percent reduced likelihood of having a positive SARS-CoV-2 PCR test for the general population and a 52 percent reduced likelihood for African Americans. The authors also reported similarities between the disease progression of COVID-19 and inflammatory bowel disease as well as inflammatory profiles of COVID-19 and asthma.
This study used state-of-the-art data analysis to find associations between SARS-CoV-2 infection and a number of biological factors; however, clinical trials are needed to confirm the efficacy of melatonin supplementation in preventing or treating infection. This study has not yet completed peer-review.
Link to full study.
Learn more about COVID-19 in these Q&As featuring Dr. Rhonda Patrick, released April 14 and June 10.
High phenolic olive oil consumption improves cognitive function in adults with mild cognitive impairment.
Mild cognitive impairment is an intermediate stage between the normal cognitive deficits commonly associated with aging and dementia. Many adults with mild cognitive impairment progress to having Alzheimer’s disease; however, interventions that increase dietary antioxidant content may improve cognitive function and prevent further decline. A recent study showed that olive oil consumption improves cognition in adults with mild cognitive impairment.
Olive oil contains monounsaturated fatty acids as well as a number of phenolic compounds that act as antioxidants, protecting the body from oxidative stress and inflammation. A growing number of studies demonstrate that olive oil may provide protection against cognitive decline.
The authors of the study recruited 50 adults who had mild cognitive impairment. They assigned participants to consume 50 milliliters of high-phenolic extra virgin olive oil (EVOO) daily, 50 milliliters of moderate phenolic EVOO daily, or to adhere to a Mediterranean dietary pattern (which is rich in olive oil, plants, and whole grains) for the duration of the study. The participants completed cognitive tests at baseline and after one year of following their diet intervention. Some participants also consented to have their DNA sequenced for the presence of the APOE4 gene. Having one copy of the APOE4 gene increases Alzheimer’s disease risk as much as threefold; carrying two APOE4 copies increases risk as much as fifteenfold.
Participants in all three groups experienced improvement in cognitive performance after one year. Participants in both of the groups that consumed olive oil demonstrated additional improvements in global cognition, letter fluency, and stability of impairment. The effects of the olive oil treatments were especially strong in participants carrying at least one copy of the APOE4 gene. The authors did not find significant differences between the olive oil types.
The authors cautioned that their small sample size may have limited their findings. They noted that both olive oils used in the study have phenol concentrations that meet the European Commission’s standard for quality olive oil, making differences in their effects harder to detect. They suggested that future studies should collect biomarkers, use imaging studies to measure disease progression, and include larger sample sizes.
Link to full study.
Psilocybin use with therapy is an effective treatment for depression
Depression affects more than 300 million people globally. Current treatment options are limited in their effectiveness and have side effects that reduce treatment adherence. Emerging research suggests psilocybin may be a safe and effective treatment for depression, with long-lasting results after one to two sessions.
Psilocybin is the psychoactive compound found in hallucinogenic mushrooms of the Psilocybe genus and others. Recent research has greatly expanded the understanding of psychedelic drugs and their effects on mental illness. For example, ketamine, a short-acting anesthetic with hallucinogenic effects, is available for use in the United States to treat depression, anxiety, and post-traumatic stress disorder. Psilocybin may provide similar benefits with a lower risk of chemical addiction, however.
Adults with depression who were not taking antidepressant medication were invited to participate in either immediate psilocybin treatment or be placed on an eight-week waitlist for treatment. Twenty-four participants completed the study treatment of two psilocybin sessions with supportive psychotherapy. The authors used a standardized rating scale called the GRID-Hamilton Depression Rating Scale (GRID-HAMD) to measure depression severity.
One week after psilocybin treatment, participants reported a statistically significant decrease in depression symptoms (average GRID-HAMD score = 8.0, mild depression) compared to those on the waitlist (average GRID-HAMD score = 23.8, very severe depression). This effect remained four weeks post-treatment with participants in the immediate treatment group reporting average GRID-HAMD scores of 8.5 compared to 23.5 in the waitlist group. Nearly three-fourths of all participants experienced a 50 percent or greater reduction in depression symptoms by four weeks following psilocybin treatment.
Previous research by these investigators has reported similar results in people with both cancer and depression. The authors suggested these findings demonstrate the ability of psilocybin-assisted therapy to produce large, rapid, and sustained improvement in people who have depression.
Link to full study.
Psilocybin expert Dr. Roland Griffiths is the corresponding author for this study. Watch this clip in which he discusses psilocybin use and mental illness.
High sugar intake increases cancer risk.
Current dietary guidelines for people living in the United States recommend limiting sugar intake to less than 10 percent of total daily calories. Despite these recommendations, evidence indicates that some people living in the United States consume as much as 23 percent of their daily calories in the form of added sugars. Findings from a recent study suggest that high dietary sugar intake increases a person’s risk for cancer.
Cancer is the second leading cause of death in the United States. Unlike normal cells, cancer cells preferentially rely on glycolysis (the breakdown of sugar) to produce energy. This altered metabolism, widely recognized as a hallmark of cancer, promotes cell proliferation and cancer metastasis.
The authors of the study drew on data from more than 101,000 participants enrolled in NutriNet-Santé, an ongoing observational cohort study based in France. Participants completed online 24-hour dietary records detailing their usual consumption of more than 3,500 food and beverage items. The authors of the study performed statistical analyses to identify associations between sugar intake and cancer risk, taking into account known risk factors, such as socioeconomic status, body size, lifestyle, medical history, and nutritional factors.
They found that higher dietary sugar intake increased the overall risk of developing cancer 17 percent. The risk of breast cancer increased 50 percent with high sugar intake. These findings suggest that reducing dietary sugar intake decreases a person’s risk of developing cancer and highlight the importance of policies and interventions to reduce intake.
The effects of sugar extend to longevity, as well. In fact, consumption of sugar-sweetened beverages is associated with dramatically accelerated telomere shortening – equivalent to as much as five years of a person’s life. Watch this clip in which Dr. Elissa Epel discusses the harmful effects of what she calls a “toxic lifestyle,” one that includes the consumption of sugary drinks.
Link to study abstract.
Related editorial
Exercise exploits the immune system to fight cancer.
Exercise is a critical component of public health recommendations to prevent cancer. A growing body of scientific research demonstrates that engaging in exercise after a cancer diagnosis can improve outcomes, but the mechanisms that mediate these effects are not fully characterized. Findings from a new study demonstrate that exercise alters the metabolism of cytotoxic T cells to improve their ability to attack cancer cells.
Cytotoxic T cells play key roles in the body’s immune response. They destroy malignant cells by triggering apoptosis – a type of cellular self-destruct mechanism that rids the body of damaged or aged cells.
The authors of the study placed mice with cancer into one of two groups. Half of the mice exercised on a treadmill, but the other half remained inactive. They transferred cytotoxic T cells from the exercised mice into the inactive mice. Then they isolated T cells, blood, and tissues from the exercised mice. Finally, the authors injected both groups of mice with antibodies that would destroy the animals’ cytotoxic T cells.
The mice that exercised exhibited slower cancer growth and reduced death rates than the inactive mice. The inactive mice that received the cytotoxic T cells from exercised mice showed marked improvements in their disease status. The exercised mice had high blood levels of lactate, which altered the T cells’ metabolism and increased the cells’ activity. Destroying the animals’ cytotoxic T cells negated the beneficial effects that the exercise had in terms of cancer growth and survival.
Taken together, these findings suggest that exercise alters cytotoxic T cells to mediate exercise-induced cancer suppression. Treatment protocols that incorporate exercise might improve outcomes by activating the immune system.
Link to full study.
A Western diet impairs odor-related learning and memory in mice.
Loss of olfactory system function – the sense of smell – is an early indicator of cognitive decline in people with type 2 diabetes and obesity. A new study in mice demonstrates the negative effects of a high-fat, high-sugar Western dietary pattern on odor-related learning and memory.
Smell is an important regulator of behavior and memory, especially in non-human animals like mice. Evidence suggests that olfactory system dysfunction is related to decreased neurogenesis in the olfactory regions of the brains. Changes in smell may signal decreased neurogenesis in other areas of the brain, which may indicate cognitive decline and Alzheimer’s disease progression.
The investigators fed mice either standard chow, a high-fat diet (54 percent of calories from fat), or a Western diet (42 percent of calories from fat, 34 percent of calories from sugar) for eight months. They measured body weight, blood glucose, olfactory learning and memory, and cellular mechanisms of smell.
After just three months of consuming a Western diet, mice showed declines in odor-related learning and memory. Weight gain and loss of glucose control were similar between the mice eating the Western and high-fat diets, but higher than among the mice eating the standard chow. After eight months, the mice consuming the Western and high-fat diets exhibited a diminished sense of smell and impaired olfactory learning and memory. However, the authors were unable to detect cellular changes related to this outcome.
These findings add to a growing number of studies investigating the role of diet, diabetes, and obesity in cognitive decline. The authors encourage future researchers to investigate the interactions between olfactory and endocrine systems in people with obesity and type 2 diabetes.
Link to full study.
Simple sugars alter gut microbiota and induce colitis in mice.
Colitis is an inflammatory bowel disease characterized by inflammation of the colon, accompanied by diarrhea and weight loss. It is caused by a combination of genetic and environmental factors and is more common among people who adhere to a Western dietary pattern high in simple sugars. New research demonstrates how consumption of simple sugars may alter the composition of the gut microbiota in a way that promotes inflammation and disease.
Akkermansia muciniphila (A. muciniphila) is a bacterial species commonly found in the human gut. It degrades mucin, a type of gelatinous protein produced by the intestines to maintain a barrier between the cells that line the gut and the gut microbiota. Dietary imbalances can cause A. muciniphila to damage the gut barrier integrity and induce inflammation. People with obesity and metabolic disease often have fewer A. muciniphila in their guts, prompting many to explore this species as a probiotic for a number of conditions.
The authors of the study first used a model of colitis that mimics environmental exposure to toxins and then replicated these results in a second model of colitis that mimics genetic susceptibility to colitis. They fed mice a diet providing 10 percent glucose by weight (similar to the sugar content of sugar-sweetened soda) or a normal diet for one week prior to the development of colitis. Mice on the high glucose diet exhibited worse colitis severity, including more diarrhea and weight loss. Mice who continued to consume a high glucose diet after developing colitis continued to experience more severe symptoms.
Through a number of intricate experiments, the authors determined that a high sugar diet increased the number of mucin-degrading bacteria such as A. muciniphila and Bacteroides fragilis. When given antibiotics (which destroy gut bacteria, including mucin-degrading species), glucose-treated mice exhibited less inflammation and less severe colitis symptoms. Finally, when genetically susceptible mice were given a fecal microbiota transplant from glucose-fed healthy mice, they developed more severe colitis, demonstrating the ability to transmit risk from one mouse to another.
This study provides new information about the effects of dietary sugars on colitis severity. The authors provided a wealth of data from a series of well-controlled experiments in mice; however, they noted that the microbiota of mice and humans are very different and clinical studies are needed to confirm these results.
Link to full study.
Learn more about eating to grow a healthy gut microbiome in our episode with Drs. Erica and Justin Sonnenberg.
A woman’s cardiovascular health influences that of her children.
Cardiovascular disease is an umbrella term that includes coronary artery disease, heart attack, and stroke, among others. Together, these diseases are the primary cause of death among people living in the United States. Findings from a recent study indicate that a woman’s cardiovascular health influences that of her children.
The study drew on data from nearly 6,000 mother-father-child triads of participants enrolled in the Framingham Heart Study, a long-term, ongoing study of cardiovascular disease risk among people living in Framingham, Massachusetts. The authors of the study scored the participants’ cardiovascular health according to the American Heart Association scoring system, ranking them as having poor, intermediate, or ideal cardiovascular health.
The study spanned nearly 72,000 person-years, during which 718 cardiovascular events occurred. Children of mothers whose cardiovascular health was ideal lived nine more years free of cardiovascular disease than those whose mothers had poor cardiovascular health. Onset of poor cardiovascular health occurred earlier among children whose mothers had poor cardiovascular health, with nearly twice the risk of early-onset cardiovascular disease compared with children of women with ideal cardiovascular health.
These findings suggest that a woman’s cardiovascular health can predict that of her children and underscore the importance of public health and clinical interventions designed to improve cardiovascular fitness.
Link to study abstract.
