Welcome to the November 2023 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, which includes NDs, MDs, PhDs, RDs, an MS clinical nutrition, an MS biology, and an LAc, summarizes the essence of several interesting recent studies.

In this issue: (1) Mental Health Moment: social jetlag and the microbiome, (2) chocolate for leaky gut, (3) food timing and diabetes risk, and (4) the Mediterranean diet preserves muscle while decreasing visceral fat.

Social Jetlag and the Gut Microbiome

Social jetlag is caused by a fluctuating pattern of sleep and wake times based on schedule changes between workdays and work-free days. These changes in sleep patterns are similar to those of shift workers, but on a smaller scale. But because circadian rhythm disruptions can impact chronic disease risk, any disruption is worth taking note of.

In this study, the researchers examined the relationship between social jetlag sleep pattern changes and the gut microbiome, as well as impacts on cardiometabolic health, in adults ages 18-65. To measure social jetlag, the participants submitted a self-reported questionnaire detailing their sleep patterns, including sleep duration and frequency of sleep disturbances. To examine the gut microbiome, at-home stool samples were collected, and typical food-intake patterns and diet quality were assessed using a food frequency questionnaire. Blood samples were collected to measure glucose, insulin, and lipid profiles.

The study found that 16 percent of participants were affected by social jetlag, with a greater than 1.5-hour difference between workday and non-workday sleep patterns. In looking at the gut microbiome variability between groups, there was a higher abundance of undesirable bacterial species in the individuals with social jetlag. Diet quality was also poorer in the social jetlag group, which is an important component to examine because diet is a key driver of microbiome makeup. Among other markers of health, anxiety was slightly elevated in the social jetlag group, as was inflammation in the male participants. Overall, this study found several connections between circadian misalignment, health risk, and lifestyle patterns, showing the importance of adequate and consistent sleep for supporting healthy living.

Note: How is your circadian rhythm? You can test the ebb and flow of your sleep-wake cycle hormones – melatonin and cortisol – with Thorne’s easy, at-home Sleep Test. Just collect saliva samples at four times during the day.

Contributed by Carly Duffy, MPH, RD

Reference

Dark Chocolate Consumption Improves Leaky Gut in Athletes

Athletes, particularly in endurance sports, are at risk for developing increased intestinal permeability, commonly called “leaky gut.” This adverse change in the ability of the intestinal wall to control absorption of particles often leads to gastrointestinal symptoms that can decrease both sports performance and overall quality of life. Certain nutrients, whether consumed as food or as supplements, can benefit the gut microbiome, gut health, and athletic performance. One such class of nutrients, antioxidants called polyphenols, are found in foods like berries, spices, and chocolate.

In a study of male soccer players, 24 elite athletes and 23 amateur athletes completed gut permeability testing, including blood levels of lipopolysaccharide (LPS), zonulin, and occludin – blood markers that provide evidence of changes in intestinal permeability. Following baseline measures, the elite soccer players were randomly assigned to one of two groups – normal diet with 40 grams dark chocolate daily or normal diet only for 30 days. After 30 days, LPS, zonulin, and occludin were measured again.

Compared to moderate exercise in amateur athletes, the intensive exercise of elite athletes was associated with higher levels of zonulin, occludin, and LPS, indicating increased leaky gut among the elite athletes. In the second phase of the study, elite athletes whose diets were supplemented with dark chocolate had no change in zonulin, occludin, or LPS levels from baseline. Conversely, participants who did not consume dark chocolate had increased markers of intestinal permeability at the end of the study. These results indicate a positive benefit of dark chocolate consumption on intestinal permeability.

Note: For athletes who need an NSF Certified for Sport® option, EnteroMend® contains L-glutamine, soluble fiber, and botanical extracts that support overall intestinal health, including decreased gut permeability.*

Contributed by Jennifer L. Greer, ND, MEd

Reference

Eating Vegetables First Improves Blood Sugar Response after Meals 

As we head into the food-filled holiday season, it is timely to highlight that how fast you eat and the order in which you consume different food groups can affect your blood sugar and insulin response. Previous research has found that eating quickly (within 10 minutes) appears to cause a significantly greater blood sugar spike than eating the same meal slowly.1 

Eighteen healthy young women (average age 21) with no family history of type 2 diabetes were divided into three groups, with each participant consuming an identical meal (671 kcal) on three separate days, with variations in food order (vegetables or carbohydrates first) and eating speed (10 or 20 minutes). 

Each test meal was given one week apart at the same time of day (9:00 a.m.) following a 12-hour fast, and consisted of protein (fish), vegetables (broccoli and tomato), and carbohydrates (white rice). Each group rotated among the following three meal patterns and participants were monitored to ensure compliance.

  • Carbohydrates (6 min), protein (7 min), vegetables (7 min) – total eating time = 20 minutes
  • Vegetables (7 min), protein (7 min), carbohydrates (6 min) – total eating time = 20 minutes
  • Vegetables (4 mins), protein (3 min), carbohydrates (3 min) – total eating time = 10 minutes

Blood samples were collected at four different points: at baseline, then 30, 60, and 120 minutes later. Blood glucose, insulin, triglycerides, and free fatty acid concentrations were examined.

The study found that eating vegetables at the beginning of the meal led to significantly lower blood sugar and insulin levels (p<0.05) at 30 minutes post-consumption compared to when rice was eaten first, regardless of whether the meal was consumed fast or slow.

Although eating slowly is certainly beneficial and can help prevent overeating, this study showcases that eating vegetables first and carbohydrates (like rice) last appears to be helpful for improving blood sugar and insulin response following meals, regardless of how fast one eats.

Note: If you are looking for digestive support to tackle your next holiday meal or the occasional overindulgence, then consider Thorne’s Advanced Digestive Enzymes.*

Contributed by Carina Toledo, MS Clinical Nutrition, MHI

References

A Modified Mediterranean Diet and Exercise Decreases Visceral Fat and Percent Body Fat and Increases Lean Muscle Mass

One concern about weight-loss programs is that individuals often lose lean muscle mass along with the fat. Therefore, it’s prudent to take steps to alleviate this problem, either with dietary choices, exercise, nutritional supplements, or all three. The current study looked at a weight-loss program and its effects on body composition.

As an interim sub-analysis of the ongoing PREDIMED-Plus study (n=6,874), a subset of participants (n=1,521; ages 55-75) from seven study centers in Spain were randomly allocated to a treatment group (n=760) or a control group (n=761). Treatment consisted of a calorie-restricted (30% lower) version of the Mediterranean diet, physical activity equivalent to 45 minutes of walking daily (six days a week), and behavioral support; the control group was told to eat a Mediterranean diet with no calorie restriction or specific dietary or behavioral counseling and were not advised to increase exercise. The entire study will last eight years and will evaluate the effects of this intervention on the incidence of cardiovascular disease. This completed interim study lasted three years and evaluated body fat and lean muscle mass (as percents of body weight) and amount of visceral fat (in grams) after one and three years; endpoints were 5-percent improvement or greater from baseline to evaluation.

At the 1-year and 3-year follow-ups, participants in the intervention group compared to the control group had:

  • Greater decreases in percent body fat
    • 0.94-percent greater reduction after one year
    • 0.38-percent greater reduction after three years
  • Greater reductions in visceral fat deposition
    • 126 grams less after one year
    • 70.4 grams less after three years
  • Greater increases in percent lean muscle mass
    • 0.88-percent greater increase after one year
    • 0.34-percent greater increase after three years

At 1-year and 3-year follow-ups, participants in the intervention group compared to baseline (starting) values had:

  • 1.14-percent total fat mass loss after one year
  • 0.52-percent total fat mass loss after three years

  • 154 grams of visceral fat loss after one year
  • 75.1 grams of visceral fat loss after three years

  • 1.07-percent total lean muscle mass increase after one year
  • 0.47-percent total lean muscle mass increase after three years

The control group exhibited negligible changes.

Overall, the improvements with the diet and exercise intervention were more significant after one year than after three years.

Note: Help maintain weight management goals with supplements that promote healthy metabolism, like Thorne’s Metabolic Health.* Support lean muscle mass during a weight-loss program with Thorne’s Amino Complex, Whey Protein Isolate, Creatine, or for a non-powder option, try NiaCel® 400.*

Contributed by Kathi Head, ND

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