Welcome to the December 2024 issue of Research Extracts. “The Extracts” is designed to keep busy practitioners and savvy consumers up to date on the latest research on diet, nutrients, botanicals, the microbiome, the environment, and lifestyle approaches to good health and wellness. Our medical team, including NDs, MDs, PhDs, RDs, an MS in chemistry, an MS in biology, and an LAc, summarizes the essence of several interesting recent studies.

In this issue: (1) Mental Health Moment: how probiotics affect mood in runners, (2) dark chocolate improves mood in postmenopausal women, (3) physical activity improves longevity, and (4) affect of dietary vitamin C on sleep.

Mental Health Moment: Protective Effects of Probiotics on Mood in Runners

Athletic performance relies on mental and physical systems working together. The gut-brain axis plays a key role in regulating digestion and mood and can influence how athletes perform and recover after exercise. Excessive or strenuous exercise has been seen to alter the gut microbiome towards dysbiosis and may contribute to other negative consequences such as inflammation or low mood. 

The present study explores the effects of probiotic supplementation on mood and inflammatory markers in marathon runners. Participants, healthy males ages 30-45 who were engaged in athletic training for at least one year and able to run a marathon, were randomly assigned to control or probiotic supplementation groups for 30 days. Daily, the probiotic group received 1 billion CFUs of a blend of Lactobacillus acidophilus, Lactobacillus lactis, Bifidobacterium lactis, and Bifidobacterium bifidum.

Blood samples, anthropometric measures, mood assessments, and food registration questionnaires were completed before and after the 30-day study period. Inflammatory markers as well as blood glucose, glutamine, and serotonin concentrations were measured.

As would be expected, tension was lower, and fatigue was higher, in both groups after the marathon was completed. However, vigor was lower after the marathon in the placebo group compared to the probiotic group, indicating that probiotic supplementation helped to preserve runners’ vigor. The total mood disturbance score was lower in the probiotic group after the marathon indicating less worsening of mood compared to the placebo group. Inflammatory markers showed improved inflammatory balance of IL-2 and IL-4 and reduced lipopolysaccharide after the marathon in the probiotic-supplemented group. 

Note: Thorne’s FloraSport 20B® is a stable, high-potency probiotic blend of clinically studied bacterial strains including Lactobacillus acidophilus and Bifidobacterium lactis that support gut health, immune function, and exercise recovery in children and adults, including athletes.*

Contributed by Carly Duffy, MPH, RD

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Eating Dark Chocolate Daily Improves Mood in Postmenopausal Women

Do you need another reason to love dark chocolate? Research studies have shown that polyphenols (antioxidants) found in chocolate have many health benefits, and dark chocolate contains more polyphenols and less sugar than other types of chocolate. Could dark chocolate decrease symptoms of depression and improve sleep in postmenopausal women? 

In a triple-blind, randomized trial, participants received either 78% dark chocolate or milk chocolate daily for eight weeks. Participants included 60 postmenopausal women (no menstruation for at least 12 months), ages 45-65, who reported mild or moderate depression using the Beck Depression Inventory (BDI). The participants consumed 12 grams of either dark or milk chocolate daily during the study period. 

Study measures included the BDI for depression symptoms, the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality, a food frequency questionnaire to ensure participants were eating their usual diet, and the International Physical Activity Questionnaire to ensure participants were maintaining their usual level of physical activity. 

After eight weeks of chocolate supplementation, compared to baseline, the mean depression score was significantly reduced in the dark chocolate group, but not the milk chocolate group, using both BDI scores and clinical diagnosis by a psychologist. However, there were no significant differences between groups in sleep quality as measured by the PSQI. While the mechanism of action by which dark chocolate consumption improves depression symptoms is not yet fully understood, the authors suggested these findings could be incorporated into nutritional counseling for postmenopausal women as this population often seeks natural solutions for managing menopause-related symptoms and eating chocolate is both easy and enjoyable. 

Note: Try a supplement with your chocolate. Thorne’s Meta-Balance provides an all-natural approach for women’s hormonal harmony.*

Contributed by Jennifer L. Greer, ND, MEd

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Physical Activity and Longevity: Key Insights from Recent Research

Physical activity is often regarded as the foundation of a healthy lifestyle, yet its potential impact on life expectancy is frequently underestimated or misunderstood. With less than half of American adults meeting current guidelines for aerobic activity, recent research highlights the profound benefits of regular movement, particularly for those who are least active. Using advanced modeling techniques, this current study evaluated the life expectancy gains associated with various levels of physical activity among Americans ages 40 and older.

The findings reveal that if all participants were as active as the top 25%, average life expectancy could increase by 5.3 years. For those in the least active quartile, becoming as active as the top 25% could result in an extraordinary gain of 11 years. While achieving this level of activity may not be realistic for everyone, there’s encouraging news: individuals in the least active group could add an impressive six hours to their life expectancy for every hour of increased activity. These findings suggest that even small efforts to move more can yield substantial benefits.

The study also examined the effort required to achieve measurable improvements across each level. For example, adding 28.5 minutes of walking per day could move someone from the least active quartile to the second, increasing their life expectancy by an average of 6.3 years. Similarly, for a person in the second quartile, adding 27.8 minutes of walking per day could add 2.8 years, moving that person from the second quartile to the third. These findings illustrate how incremental changes in daily activity can significantly enhance longevity.

Small environmental and societal changes can support these efforts. Creating walkable neighborhoods, investing in green spaces, and promoting active transportation can help individuals incorporate movement into their daily lives. These initiatives not only improve individual health but also enhance public wellness by addressing disparities in access to physical activity opportunities. Furthermore, they could increase the number of adults meeting aerobic activity guidelines.

Note: This research reinforces the idea that small, consistent increases in physical activity can lead to significant gains in both individual and population-level health outcomes. It serves as a reminder that it’s never too late to start moving more – modest efforts can deliver lasting benefits, extending both the quality and length of life.

Contributed by Ashley Huber, MS

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Dietary Vitamin C and Sleep Disorders

Several studies have found correlations between low vitamin C (either serum levels or dietary intakes) and several sleep disorders, including sleep apnea, insomnia, sleep deprivation memory impairment, and restless legs syndrome. This current study sought to add to this body of literature by examining the relationship between dietary vitamin C intake and sleep over a long period of time. Data of 68,221 participants from the UK Biobank were collected at several timepoints starting in 2006 and ending in 2023. Vitamin C intake was assessed via 24-hour dietary recall questionnaires.

Dietary vitamin C intake in the highest quartile (132.88-191.51 mg/day) was associated with improved sleep. Dietary vitamin C intake in this range resulted in a 22% decreased risk of having a sleep issue. When analyzed by disorder, higher intakes were specifically associated with a 25% decreased risk for sleep apnea. When stratified (narrowed down) by gender and age, men under age 60 were those who most benefited. 

Why does vitamin C benefit sleep? The authors speculate it’s because of vitamin C’s antioxidant effects in addition to its effect on balancing inflammation. In this study, higher dietary intakes of vitamin C were associated with lower levels of C-reactive protein, a measure of inflammation in the body. 

Note: It would be quite easy to obtain the necessary amount of vitamin C from diet alone. For example, some of the foods highest in vitamin C include: ½ cup red bell pepper (95 mg), ¾ cup of orange juice (93 mg), ¾ cup of grapefruit juice (70 mg), and 1 kiwifruit (64 mg). Thorne also offers vitamin C in both capsule and powdered forms.

Contributed by Kathi Head, ND

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