Newsletter #016: Low muscular strength linked to higher mortality risk 💪
Another Saturday has arrived, and so too has the latest HumanOS newsletter! Here we share our work, as well as various studies and media that grabbed our attention and found their way onto our social media channels.
This week, Greg released the first of a two-part series addressing a very important question - one that has probably come up for everyone who is health-conscious: how does dietary protein affect aging? Dan has previously written about how both fasting and protein-restriction are associated with increased lifespan, at least in animal models. Yet we also know that protein is crucial for maintaining a robust musculoskeletal system, which is pretty important for the quality of life (not to mention looking good in a swimsuit). How do we reconcile this? In the blog, Greg explains the role of protein in various signaling pathways associated with growth, metabolism, and regulation of muscle protein synthesis, and how all of this ultimately impacts aging and longevity. This is a long-ish piece, but loads of interesting and useful info here - definitely worth the read!
This Week’s Research Highlights
💪 People with weaker muscles may not live as long as their stronger counterparts.
Researchers at the University of Michigan analyzed data from a nationally representative sample of 8326 older adults. Participants had their grip strength measured using a dynamometer. After adjusting for potential confounders such as sociodemographic factors and co-morbidities, they researchers found that people with low muscular strength were 50% more likely to die prematurely.
👶🏻 Babies in strollers can be exposed to ~60% more pollution than adults.
Researchers reviewed data on pollution exposure of babies in strollers. They determined that infants in strollers breathe in up to 60% more polluted air than adults, because they are positioned in line with vehicle exhaust pipes. Regarding the findings, Professor Prashant Kumar says: "We know that infants breathe in higher amounts of airborne particles relative to their lung size and body weight compared to adults. What we have proven here is that the height most children travel at while in a pram doubles the likelihood of negative impacts from air pollution when compared to an adult.”
🦠 Soil exposure modifies the gut microbiota and supports immune tolerance in a mouse model.
Researchers housed mice on either clean bedding or soil, then analyzed their gut microbiota and immune parameters. They found marked differences in the composition of the gut microbiome of mice who lived in contact with soil. Furthermore, exposure to soil polarized the immune system toward TH1 and increased anti-inflammatory signaling, alleviating TH2-driven inflammation and allergic responses. The researchers suggest this may explain why exposure to natural environments, such as farms, is linked to reduced risk of allergic disease in humans.
🥚 Increasing the amount of protein in the diet may reduce fat in the liver in people with NAFLD.
Researchers recruited 25 volunteers who used a low-calorie diet for eight weeks to lose up to 8% of their body mass. Afterwards, the participants were instructed to maintain their weight for two years, and did so using either a moderate-protein or a high-protein diet. The researchers determined that protein intake was linked to reduced liver fat in the participants, independent of BMI. Furthermore, more than half of participants who had been previously diagnosed with non-alcohollic fatty liver disease no longer had the condition.
Podcasts We Loved This Week
- Alan Jasanoff: The Biological Mind. Via The Brain Science Podcast.
- Elise Facer-Childs: Circadian Phenotypes, Brain Function & Athletic Performance. Via Sigma Nutrition Radio.
New humanOS Content
- Blog: Dietary Protein and Aging: mTOR, IGF-1, and Tradeoffs (Part 1). By Greg Potter.
Media Featuring humanOS
Sodium intake is associated with cardiovascular disease and strokes only in communities where the mean intake was >5 grams per day.
This was the main finding of an analysis of associations between community-level mean sodium & potassium intake, cardiovascular disease, and mortality.
Daily supplementation with collagen improves skin elasticity.
Subjects who consumed a supplement containing 4000 mg of hydrolyzed fish collagen experienced a 40% increase in skin elasticity, as well as a 43% reduction in joint pain and 39% increase in joint mobility, compared to placebo.
The humanOS Bookshelf
The Body Keeps the Score by Bessel van der Kolk.
Greg says: Trauma often leaves indelible psychological scars. But what effects do these blemishes have on long-term health? Van der Kolk spells the answers out very clearly in this brilliant, underrated book.