Newsletter #037: Junk Food Diet Increases Risk of Depression 🍔🍕
Welcome to the latest edition of the humanOS newsletter! Here, we’ll share our work, plus some of the cool studies and media that we reviewed this week and that found their way onto our social media channels. 🤓
This Week’s Research Highlights
Researchers estimated cumulative phthalates exposure from metabolite concentrations in urine samples from 10253 subjects. They found a consistent positive association between dining out and levels of phthalates across the study population. Among adolescents, high consumers of foods outside the home had 55% higher phthalate levels, compared to those who only consumed food at home. In general, children had higher levels.
Researchers analyzed data from 11 studies that recorded the presence of depression or depressive symptoms in >100000 participants - as well as documentation of the composition of their diets. Across all studies, subjects who ate more foods known to promote inflammation - fast food, processed meats, cakes, etc - were found to be about 40% more likely to develop depression. It is thought that pro-inflammatory nutrients, which are abundant in the modern Western diet, may elicit inappropriate innate immune system activity. This leads to chronic low-grade inflammation and potentially depressive symptoms.
Researchers analyzed the activity of urolithin A, a microbial metabolite derived from pomegranate and berries, in an animal model as well as in cell cultures. They found that urolithin A reduces gut inflammation and increases proteins that tighten epithelial cell junctions in the gut. Tight junctions in the gut barrier prevent toxins and microorganisms from leaking out.
Researchers measured BMI and waist-to-hip ratio in 9652 people, then used magnetic resonance imaging to determine brain volumes. Individuals with high BMI and high waist-to-hip ratio had lower gray brain matter volume. Specifically, subjects who had a high BMI and a high waist-to-hip ratio had the lowest average gray matter brain volume of 786 cubic centimeters - compared to people of healthy weight who had an average gray matter brain volume of 798 cubic centimeters. Gray matter contains most of the brain's nerve cells and includes brain regions involved in self-control, muscle control, and sensory perception.
Podcasts We Loved This Week
- Julian Abel: Building Compassionate Communities to Improve Public Health. Via Nourish Balance Thrive.
- Wael Jaber and Maia Smith: Exercise Actually Remodels Your Heart. Via Science Friday.
- Lauren Morello: Science Put On Pause Under The Government Shutdown. Via Science Friday.
Products We Are Enjoying
Ginny says: We know that exposure to bright light (especially short wavelengths) during the day promotes alertness, cognition, and other benefits. One study, for instance, found that people who were exposed to more sunlight during their workday were more physically active and got an additional 46 minutes of sleep per night. But intense full-spectrum light is pretty hard to come by this time of year when the days are short, overcast, and chilly. 😭 That is why I got these bulbs for my office. They are super bright (1000 lumens), emit a white light rather akin to sunlight (6000K), and the bulbs themselves even have a fun retro design. Just make sure not to use them at night, or for taking selfies (that cool bluish-white is, um, not the most flattering light).
New humanOS Content
- Blog: Considering Genetic Testing? Here Are Some Things to Think About. By Greg Potter.
This week on the blog, Greg addressed a very timely issue: personalized genetic testing. Part of why these genetic testing kits, like 23andme, have been somewhat controversial is the question of how this knowledge might affect the consumer, both psychologically and behaviorally. Does the information help enable people to modify their lives in ways that maximize their health and function? Or does it make them feel disempowered, due to what they might perceive as inescapable constraints on their physical potential?
A team of scientists from Stanford designed a fascinating series of experiments to answer this question. In short, they sequenced participants’ DNA, assessing for particular genetic risk groups associated with either exercise capacity or appetite regulation and then tested the actual impact on exercise performance/satiety when people found out about their genetic predispositions.
But here’s the interesting wrinkle - some people were given false information in their gene report (for instance, some folks were instructed that they had the risk variant of a gene related to obesity when in fact they had the protective version of a said gene). The results were pretty eye-opening. If you wanna know what happened, check out the blog!