Newsletter #012: Impact of Sleep Restriction, and Ketogenic Diet on Health 🥗
Happy weekend friends, and welcome to the latest HumanOS newsletter! Here we highlight our work, as well as some research and media that we found useful and interesting.
This week, Dan interviewed Dr. Mike West, CEO of AgeX Therapeutics. Dr. West has quite an impressive background as a pioneer in stem cell research - he coordinated the first collaborative effort to isolate human embryonic stem cells for use in regenerative medicine. Now he is focused on developing novel therapeutics that target human aging. This is a fascinating discussion, on a subject that is directly relevant to every single one of us. Imagine if we could perfectly recover from injuries, regrow lost limbs or failing organs, and maintain physical and cognitive performance throughout life. There are organisms that exhibit remarkable regenerative capacity and even approach biological immortality - perhaps we can learn from them. Definitely check out this interview while you’re out for a walk sometime, or drinking a cup of chamomile tea 🍵
This Week’s Research Highlights
🥱 Two nights of sleep restriction decreases whole‐body insulin sensitivity in healthy young males.
Researchers recruited ten healthy young men, and had them go through two experimental conditions, each separated by a 3-week washout period. In one condition, participants got two nights of normal sleep, and in the other they spent two nights in which their sleep was restricted to half of their habitual sleep duration. After the second night of each condition, participants underwent an oral glucose tolerance test. After two nights of sleep restriction, plasma insulin area under the curve was higher after sleep restriction compared to the control, and the Matsuda index (an assessment of whole-body insulin sensitivity) was 18.6% lower.
👴🏻 Older adults who engage in strength training at least twice per week were shown to have 46% lower odds of all-cause mortality.
Researchers at Penn State analyzed data on physical activity habits from 30,162 older respondents to a large health interview survey, which was linked to death certificate data. The researchers found that older adults who reported engaging in strength training at a frequency concordant with current guidelines had 46% lower odds of dying from any cause, compared to those who did not adhere to strength training recommendations. This association remained after adjustment for medical history and health behaviors.
🥗 A ketogenic diet improves mitochondrial biogenesis and bioenergetics via the PGC1α-SIRT3-UCP2 axis.
To examine how ketogenic diets work therapeutically in refractory epilepsy, researchers examined mice with a mutation in the mitochondrial DNA repair mechanism UNG1, which causes them to develop progressive mitochondrial dysfunction. When these rodents were fed a ketogenic diet, they showed improvements in markers of mitochondrial biogenesis, apparently by upregulating the PGC1α-SIRT3-UCP2 axis. Notably, mitochondrial levels of UCP2 were higher in hippocampal neurons of mice red the ketogenic diet, versus those fed a standard diet. Similar effects were also noted with in vitro exposure of cells to the ketone body β-hydroxybutyrate.
Podcasts We Loved This Week
- Stephan Guyenet: The Reason You're Overeating. Via Muscle, Mindset, and Meal Prep.
- John Ioannidis: What Happened to Evidence-based Medicine? Via Rationally Speaking.
- Ian Dunican: The Impacts of Caffeine On Sleep & Circadian Rhythms in Athletes. Via Dr. Bubbs' Performance Podcast.
Products We Are Enjoying
Chamomile tea.
Ginny says: I started drinking chamomile tea because it was supposed to be good for relaxing and decompressing, though I was skeptical that there were any real underlying biological mechanisms. However, it looks like there might be something to it. Chamomile is one of the richest sources of apigenin amongst edible plants, and a number of studies have indeed suggested that apigenin has mild anxiolytic and antidepressant effects in animal models, perhaps by binding to GABA-A receptors. And the long-term effects on health may be even more compelling - flavones like apigenin appear to be anti-inflammatory and anti-carcinogenic. This may be why women who drank chamomile tea regularly had a 29% reduced risk of all-cause mortality compared to non-users, even after adjusting for health behaviors and other confounders.
Content and Features humanOS
- Blog and podcast: Stem Cells Will Soon Change the Potential of Human Healthspan (Interview with Dr. Mike West, CEO of AgeX Therapeutics).
- New Feature: We will soon be releasing the daily Performula! Every morning, you will receive daily workouts and recipes. Workouts will include mobility, yoga, and HIIT, so you can pick something that fits your desired activity level for the day (most of us aren’t up for sprint intervals every single day), and recipes will be featured items from our library of recipe packs. You will be able to activate or pause the Performula subscription whenever you wish from Account Settings on your humanOS dashboard.