Welcome to the July 2020 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 studies.

This issue looks at lifestyle factors that influence various aspects of health: (1) diet and acne, (2) work-home boundaries and stress, (3) what makes a centenarian, and (4) protein and exercise to prevent muscle wasting.  

You really are what you eat

Remember how mom told you that if you ate too many sweets or fried foods then it would make your skin break out? Turns out she was probably right. Although casual observations have long been made connecting diet to acne, the data to support such a connection is lacking, so the connection is usually written off as opinion rather than science. However, this observational study of 24,000 adults with acne now lends credibility to a connection.

The study, a part of a larger, ongoing dietary survey of adults in France, identified that 46 percent of participants had current acne or a history of acne. Comparing the occurrence of acne with dietary patterns, researchers determined that intake of milk and sugar-sweetened beverages, and consumption of fatty and high-sugar foods, correlated with adverse skin symptoms.

Although an observational study of this kind is not designed to determine a mechanism behind the connection, the study does lend support to the theory that a high-fat, high-sugar diet leads to inflammation, oxidative stress, and higher circulating levels of hormones, such as insulin-like growth factor 1 (IGF-1), that contribute to poor skin health.

Contributed by Jacqueline Jacques, ND


  • Penso L, Touvier M, Deschasaux M, et al. Association between adult acne and dietary behaviors: findings from the NutriNet-Santé Prospective Cohort Study. JAMA Dermatol. Published online June 10, 2020. doi:10.1001/jamadermatol.2020.1602

Does greater boundary control affect after-work stress?

Increases in technology give workers the flexibility to efficiently complete work-related tasks away from the office. While this can be beneficial because it allows for more time at home with family, a constant connection to work can lead to a blurring of work-family boundaries and increased outside-of-work stress.

This research study examined the factors that contribute to boundaries between work and family and how varying levels of boundary control can affect after-work stress. Employees who reported less boundary control/greater demands on work-family boundaries were more likely to experience negative thoughts about work, a negative mood, and poorer sleep.

Implementing technological boundaries, such as keeping work email notifications turned off outside of work hours, was more likely to lead to a reduction in after-work stress than communication boundaries (example: setting expectations for communication outside of work hours). In addition, working for a supervisor who is supportive of work-family boundaries and the perception of fewer expectations on those boundaries resulted in less negative thoughts about work.

Contributed by Jennifer Greer, ND, MEd


  • Park Y, Liu Y, Headrick L. When work is wanted after hours: Testing weekly stress of information communication technology demands using boundary theory. J Organ Behav 2020. https://doi.org/10.1002/job.2461
  • Full text is available here

For more suggestions regarding successfully working from home, check out these Take 5 blog posts:

Factors that contribute to living to 100

I have long been intrigued with the topic of longevity and the factors that contribute to a person living to age 100. Apart from the mythical Shangri-La in the Himalayas where everyone was happy, healthy, and almost immortal, what factors contribute to longevity?

My grandfather lived to be 100 and, in addition to some longevity genes, his lifestyle most likely contributed. During the summers we visited my grandparents at a lake in Northern Minnesota and I recall the following three things about him: He always pushed back from the table when he felt satisfied – none of this having to “clean his plate,” he walked a mile or two every day, and after lunch he took a nap. He also lived in his own home and taught piano lessons until he was 99.

So I was interested in the results of a new study that examined longevity factors in Washington State. The researchers looked at mortality data between 2011 and 2015 for 144,665 individuals and developed a model for predicting the likelihood of adults age 75 or older becoming centenarians. They looked at demographics, including gender, race, marital status, education, and socioeconomics.

They also studied issues associated with a person’s geographic area, including neighborhood walkability, access to easy transit, percent of neighborhood population of working age (defined as 15-64), easy accessibility to primary care physicians (defined only as MDs and DOs), rural versus metropolitan, air pollution estimations, and green space exposure from satellite images. Specific diet and lifestyle factors like exercise were not taken into account because the evaluation was on deceased persons.

The study yielded the following factors:

  1. Women are more likely than men to reach 100.
  2. Caucasians are more likely to become centenarians (they did not stratify by race other than to look at “white” and “non-white”)
  3. Individuals who are unmarried, divorced, or widowed are more likely to reach 100 than those who are married at the time of death; a factor at odds with previous research.
  4. Lower educational status increased the odds of reaching 100 – with those not receiving a high school diploma having the greatest chance; another factor that varies from previous research and seems to contradict the next factor.
  5. Individuals with higher socio-economic status are more likely to become centenarians.
  6. Geographically, those living in neighborhoods with the greatest walkability and the highest percentage of working age population have a greater chance of living to age 100.

Contributed by Kathi Head, ND


  • Bhardwaj R, Amiri S, Buchwald D, Amram O. Environmental correlates of reaching a centenarian age: analysis of 144,665 deaths in Washington State for 2011-2015. Int J Environ Res Public Health 2020;17(8):2828. Published 2020 Apr 20. doi:10.3390/ijerph17082828
  • Access full text here

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Regular exercise and protein intake significantly impact muscle quality  

Sarcopenia – age-related muscle loss – is a common health issue of aging. Using magnetic resonance imaging (MRI) to measure the functional cross-sectional area and intramuscular adipose tissue of upper and lower leg muscles in 49 younger (ages 20-35) and 49 older (ages 50-65) adults as a more robust measure of muscle quality than cross-sectional area alone, researchers investigated the relative influence of age, gender, exercise, and protein intake on muscle quality (larger size and lower fat).  

Participants in the study (53% female) provided a health history and completed a three-day food diary, self-assessment of exercise habits, and MRI of the knee extensor and plantar flexor regions.

More active adults (aerobic and resistance exercise at least 3 times weekly) had significantly higher protein intake than sedentary (aerobic or resistance exercise once a week or less) individuals, but none were below the recommended daily allowance for protein. Quantity of intramuscular adipose was significantly higher in older versus younger participants and in sedentary versus active participants.  

The study found that gender, age, exercise, and protein intake accounted for 71 percent of the variance in knee extensor (upper leg) muscle size between individuals.

Exercise and protein intake accounted for more than half of the 71 percent. The specific intensity of physical activity was not a significant predictor. Bottom line: If you want to keep your muscles strong and healthy in old age, eat your protein and get your exercise.

Contributed by Sheena Smith, MS MA


  • Dicks N, Kotarsky C, Trautman K, et al. Contribution of protein intake and concurrent exercise to skeletal muscle quality with aging. J Frailty Aging 2020;9(1):51-56. doi:10.14283/jfa.2019.40

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