Newsletter #125: Microplastics, Depression, and Night Eating 🥡
Welcome to the latest edition of the humanOS newsletter!
This week, we learned that exercise significantly raises insulin sensitivity and cardiorespiratory fitness and lowers all-cause mortality in people with type 2 diabetes; the number of people experiencing depressive symptoms in the US has gone up three fold since the start of the pandemic; tiny bits of plastic are probably accumulating in the filtering organs of your body; and eating late at night on a regular basis is linked to increased arterial stiffening, a major etiological factor in the development of cardiovascular disease.
See below for more info, and please stay safe everyone. 👇
This Week’s Research Highlights
🏋 High-intensity interval training (HIIT) dramatically improves insulin sensitivity and cardiorespiratory fitness.
Researchers recruited 48 men, including 15 with type 2 diabetes and two age-matched groups of healthy non-diabetic men (15 obese, and 18 lean). Participants were all enrolled in a supervised HIIT program of 3 training sessions per week. These sessions consisted of blocks of 5 x 1 min bursts of exercise interspersed with 1 min rest, shifting between blocks on stationary cycles and rowing machines. After eight weeks of this program, all participants showed significant improvements in insulin sensitivity. In subjects without diabetes, average increases of 32-37% were observed. The increase in insulin sensitivity among the diabetic group averaged 44%, and fasting blood sugar and HbA1c also dropped. The men all became fitter as a result too: VO2 max increased by 10% in the nondiabetic subjects, and 15% in the group with type 2 diabetes.
🏃 Higher levels of exercise is linked to significantly lower all-cause mortality in people with type 2 diabetes.
Researchers analyzed data from 4859 participants with type 2 diabetes in the National Health Interview Survey (NHIS) and the National Health Insurance research database in Taiwan. The study used information about the characteristics of each participant, including their socioeconomic status, health behaviors, and exercise habits obtained from surveys performed in 2001, 2005, 2009, and 2013. They determined that greater exercise capacity was linked to lower risk of mortality in these subjects, compared to those who were inactive. Specifically, individuals who performed a moderate amount of exercise (defined as 0-800 kcal/week energy expenditure) had a 25% lower all-cause mortality rate, while those who were classed as having a high exercise level (defined as more than 800 kcal/week energy expenditure) had a 32% lower all-cause mortality risk.
📈 The number of adults experiencing depression in the US has risen three fold.
Researchers examined data from two nationally representative surveys. One was from before the COVID-19 pandemic, including 5065 respondents from NHANES 2017-2018, and one was from during the pandemic, derived from 1441 participants in the COVID-19 and Life Stressors Impact on Mental Health and Well-being study. Depression symptom prevalence was higher in every category during COVID-19 compared with before. As of mid-April 2020, 27.8% of Americans had depression symptoms, compared to just 8.5% before the pandemic. Notably, lower income and having less than $5000 in savings was linked to greater risk of depression symptoms.
🔬 Microscopic plastic particles are probably distributed throughout your organs - with uncertain long-term effects.
Researchers analyzed 47 tissue samples for microplastic and nanoplastic particles - particles that would be small enough to transfer from the digestive system into the bloodstream, where they could then circulate throughout the body. They found evidence of plastic contamination in samples of lung, liver, spleen, and kidneys taken from cadavers. Previous research has shown that people consume, on average, about five grams of plastic every week, and it is nearly impossible to fully avoid it. There is concern that these chemicals may function as endocrine disruptors, but also that they could function as physical irritants, elevating risk for cancer much like asbestos.
🍕 Habitual eating at night is associated with hardening arteries.
Researchers recruited 7771 adult participants without cardiovascular disease, cancer, or diabetes mellitus at baseline. Participants were categorized into 3 groups based on self‐reported night‐eating habits: never/rarely, sometimes (1–5 times per week), or most days (6+ times per week). Arterial stiffness was assessed by brachial‐ankle pulse wave velocity at baseline and repeatedly during follow‐ups. Over a mean follow-up of 3.19 years, the frequency of eating at night was positively correlated with progression of arterial stiffness.
The adjusted difference in brachial‐ankle pulse wave velocity change rate between the group that ate at night most days and the group that never or rarely ate at night was 14.1 cm/s per year. This association was independent of total energy consumption, diet quality, insomnia, menopausal status, and other major risk factors for cardiovascular disease.
Podcasts We Loved This Week
- Alan Flanagan: Do diets even work in the long term? A look at weight loss maintenance. Via Sigma Nutrition Radio.
- Irene Davis: Evolution of the foot, running injuries, and minimalist shoes. Via The Drive.
- John Balmes: Fires outside, virus inside - how wildfires make the virus more dangerous. Via Social Distance.
Products We Are Enjoying
Good Foods Plant-based Queso
This dip is tasty, healthy, versatile - I put it on just about anything that I’m eating. It’s a very simple product, made out of cauliflower, bell pepper, and almonds, and it’s not super energy dense (just 45 calories per 30 gram serving). I’ve seen it at Target and Aldi, but you may be able to find it at other grocery stores in your area.