Welcome to the May 2021 edition 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. Our medical team, which includes NDs, MDs, PhDs, RDs, an MS, and an LAc, has summarized the essence of several of the most interesting recent studies.

In this issue you will find new studies on how lifestyle factors can influence your health in several ways: (1) exercise and COVID outcomes, (2) breakfast timing and diabetes risk, (3) stress and fast-food consumption, and (4) restaurant/fast food and mortality.

Significant reduction in serious outcomes with regular exercise prior to COVID-19 diagnosis 

As part of the ongoing effort to improve COVID-19 outcomes, a research study investigated whether regular exercise is associated with reduced hospitalization, need for ICU admission, or death due to COVID-19. The study, which took place prior to the approval of COVID-19 vaccines, included 48,440 adult COVID-19 patients (61.9 percent female, mean age 47.5 years, mean BMI 31.2) who had existing medical records documenting the amount of regular exercise they had the prior two years.

The participants were divided into three groups – those consistently inactive (0-10 min/wk accounting for 14.4 percent of the cohort), somewhat active but below the recommended amount (11-149 min/wk; 79.2 percent), and a third group that regularly met the physical activity guidelines (≥ 150 min/wk; 6.4 percent).

The study identified a significantly lower risk of hospitalization, ICU admission, and death due to COVID-19 in the group who completed the recommended amount of exercise on a regular basis. The group exercising less than the recommended amount of exercise had less risk than the inactive group, although the reduction was not always significant.

Adjusting for known factors that increase COVID-19 risk, such as older age, male gender, and pre-existing conditions like heart disease and obesity, subjects in the inactive group were 2.26 times more likely to be hospitalized, 1.73 times more likely to require ICU admission, and 2.49 times more likely to die than patients who were regularly getting the recommended amount of exercise (150 min/wk of moderate-to-vigorous activity).

Subjects who got some exercise were 1.89 times more likely to require hospitalization, 1.58 times more likely to be admitted to the ICU, and 1.88 times more likely to die compared to patients who got the recommended amount of exercise. Interestingly, only older age and history of organ transplant carried a higher risk of hospitalization or death than lack of exercise, and few other factors were riskier for ICU admission. 

Contributed by Sheena Smith, MS MA

  • Sallis R, Young D, Tartof S, et al. Physical inactivity is associated with a higher risk for severe COVID-19 outcomes: a study in 48 440 adult patients. Br J Sports Med Published online April 13, 2021:bjsports-2021-104080. doi:10.1136/bjsports-2021-104080
  • Full text available here

Eating breakfast before 8:30 a.m. and diabetes risk

Incidence of metabolic disorders like insulin resistance, diabetes, and metabolic syndrome are on the rise in the United States. Researchers are seeking to better understand how diet and lifestyle can address the growing concern related to these disorders.

Because prior studies show that intermittent fasting improves metabolic health, these researchers assessed whether first meal timing affected metabolic measures. The study, presented virtually at the Endocrine Society’s annual meeting, showed that breakfast timing might lower the risk of developing type 2 diabetes. The study found that individuals who began eating earlier in the day had lower blood glucose levels and less insulin resistance, regardless of their food timing and period of fasting during the hours prior.

Data from 10,575 adults was analyzed to determine if eating duration and timing were associated with fasting blood glucose levels and estimated insulin resistance. Participants were divided into three groups based on the duration of daily food intake. The three groups included food intake limited to less than 10 hours, food intake between 10 and 14 hours, and food intake over more than 13 hours per day. From these initial three groups, six subgroups were created based on first mealtime before or after 8:30 a.m.

Fasting blood glucose levels did not significantly differ among the three interval groups. Insulin resistance was higher among those with the shortest eating interval duration, but lower across all groups who had a first mealtime before 8:30 a.m. Overall, participants who started eating before 8:30 a.m. had lower blood sugar levels and less insulin resistance, which could reduce the risk of developing type 2 diabetes.

Contributed by Amanda Frick, ND, LAc

Addressing stress might improve fast food and fatty food intake

Weight gain, low income, and obesity are associated with high levels of stress, and chronic stress is associated with a greater preference for high-fat foods and fast foods. Likewise, the risk of being overweight or obese increases in individuals with low income, who often report higher stress. Although the link between stress and food intake is established, previous research has not investigated whether a stress-reduction lifestyle intervention could affect food intake.

In this study, low-income, overweight or obese women (6 weeks to 4.5 years postpartum) were evaluated for stress and food intake. One group received a stress reduction program with videos and peer support group visits, while the second group received reading materials on stress, exercise, and healthy eating. The intervention lasted 16 weeks.

The stress reduction intervention improved overall food intake by decreasing consumption of fat and fast food. The authors noted these results are important because helping patients reduce stress can lead to greater improvements in diet among low-income individuals, specifically noting that a 2-point stress reduction could yield a 14-percent decrease in fat intake.

Contributed by Jennifer Greer, ND, MEd

  • Chang M, Brown R, Wegener D. Perceived stress can mediate the associations between a lifestyle intervention and fat and fast-food intakes. Nutrients 2020;12(12):3606. doi:10.3390/nu12123606
  • Full text available here

And decreasing fast-food consumption could save lives, according to this next research study.

Does “eating out” shorten your lifespan?

Frequent fast-food consumption is known to have negative health consequences. But does eating any restaurant food – whether it’s McDonalds or fine dining – have a similarly negative impact on health? A recent study set out to find out.

In a large study of 35,084 adults (ages 20 and older), the frequency of eating meals prepared outside the home (fast food, sit-down restaurants, vending machines, food carts, or prepared food from a grocery store) was examined in terms of risk of all-cause mortality and cause-specific mortality (from cardiovascular disease [CVD] and cancer). Data from the National Health and Nutritional Education Survey (NHANES: 1999-2014) was used. There were 2,781 deaths during 291,475 person years of follow-up – 511 from CVD and 638 from cancer. Frequency of eating non-home cooked food was classified as less than one meal per week, 1-3 meals per week, 4-6 meals per week, 7-13 meals per week, or two or more meals daily. When comparing the lowest frequency (less than once a week) to the highest frequency (two or more times daily), those who ate out the most had the highest all-cause mortality (hazard ratio: 1.49). The association was stronger for those with lower family income.

It’s probable that many of the meals came from fast food, particularly since the lower income group had a higher all-cause mortality. But even meals from “nice” restaurants tend to be larger portion, higher in fat and sodium, and lower in vegetables and fiber. Too often, vegetables are an afterthought on the plate, if there at all.

Contributed by Kathi Head, ND

Some take-away messages from these studies:

  1. Exercise helps COVID outcomes
  2. Eating breakfast early can decrease risk for type 2 diabetes
  3. Decreasing stress can decrease the tendency to eat fast food
  4. Eating food prepared at home more often can decrease mortality from any cause