Newsletter #052: How to Eat Mediterranean, and Why Exercise Makes You (and Your Future Kids) Smarter 🥙
Hello Friends!
Welcome to the latest edition of the humanOS newsletter! Here is where we share our work, and the various studies and media that captured our attention this week. 🤓
New humanOS Content
This Week’s Research Highlights
👶 Children are more sensitive to the melatonin-suppressing effect of blue light than adults.
Researchers recruited 22 children and 20 adults for an experiment spanning two nights. On the first night, they collected saliva samples from the subjects under dim light (<30 lux) to determine dim light melatonin onset. On the second night, the researchers compared the effects of light in two different color temperatures (3000 K and 6200 K) on melatonin suppression in the participants. Melatonin suppression in children was greater than in adults in both color temperatures, and the impact of blue-enriched LED light on subjective sleepiness was greater.
💊 Consumption of propionate, a common food additive, has been linked to metabolic dysregulation.
Supplementation with propionate increased norepinephrine release by the sympathetic nervous system, leading to an increase in circulating glucagon and the adipokine fatty acid–binding protein 4 (FABP4). This surge in hormones impairs insulin action and elevates blood sugar levels in both humans and rodents. Long-term exposure of mice to a daily low dose of propionate resulted in gradual weight gain and insulin resistance. Notably, higher plasma propionate concentrations directly correlated with insulin resistance in human participants in the DIRECT trial, and reductions in propionate were associated with improved insulin sensitivity.
🧠 The positive effects of exercise on cognition may be transmitted across generations.
Researchers administered memory tests to a group of male mice, then put some of them on a six-week exercise regimen. The rodents were tested again on memory, and the mice that exercised performed better than sedentary controls. An examination of the brains revealed subtle alterations in the structure of the brain, as well as enhanced neurogenesis. More remarkably, the offspring of the mice who had exercised also performed better on memory tests than those of the controls - and they showed similar changes in their brains.
💽 Just one exercise session increases activation in brain circuits associated with memory in older adults.
Researchers measured brain activity (via fMRI) in healthy older adults who were asked to perform a task that tests semantic memory (identifying famous and non-famous names). The test was performed 30 minutes after a moderately intense (70% max effort) exercise session and on a separate day of full rest. Exercise was associated with significantly greater activation in the semantic memory network (specifically in the middle frontal, inferior temporal, middle temporal, and fusiform gyri, and in the hippocampus).
🫀 Light physical activity may substantially lower heart disease risk in women.
Researchers followed more than 5800 older women for five years. Participants wore accelerometers for seven consecutive days to record amount and intensity of activity, and the researchers divided subjects into four groups based on activity levels. Women in the highest quartile of light physical activity (think gardening, housework, walking around) were found to have a 42% reduced risk of heart attack or coronary death, and a 22% reduced risk of incident cardiovascular disease events.
Podcasts We Loved This Week
- Gabor Mate: Jungle To Civilization - Health In a Toxic Culture. Via the MAPS Podcast.
- Matthew Walker: The penetrating effects of poor sleep from metabolism to performance to genetics, and the impact of caffeine, alcohol, THC, and CBD on sleep. Via the Peter Attia Drive podcast.
Products We Are Enjoying
V8 Hydrate.
Ginny says: This stuff is basically flavored sweet potato juice and water, so the taste is interesting (probably why the Amazon reviews are so polarized), but I actually like it. It’s refreshing and has just 10 grams of sugar. If you’re doing something more intense or prolonged, or in hot weather, I think something like Gatorade will still be your best bet, but this is a solid choice for boosting energy and rehydrating during light/intermittent activity. Definitely a bit of an acquired taste!
