Newsletter #114: Spermidine, Carotenoids, and REM Sleep 💤
Hello Friends!
Welcome to the latest edition of the humanOS newsletter! Below, as usual, is our own work, plus a roundup of the various studies and other media that we came across. 🤓
This week, we learned that higher levels of vitamin C and carotenoids (likely an indicator of fruit and veggie consumption) are linked to reduced risk of type 2 diabetes, eating more spermidine seems to keep your brain healthy (more good news for fruits and vegetables), and getting adequate REM sleep seems to be super important for living a long time.
Check it out, and stay safe everyone. 👇
This Week’s Research Highlights
🍊 High blood levels of vitamin C and carotenoids are associated with lower risk of developing type 2 diabetes.
Researchers analyzed data from participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. They examined plasma levels of vitamin C and carotenoids as an objective indicator of fruit and vegetable consumption in 9754 subjects who developed type 2 diabetes, as well a comparison group of 13662 subjects who had remained free of diabetes during follow-up. After adjusting for a wide array of risk factors for diabetes, they found that higher blood levels of both vitamin C and carotenoids, as well as their sum, were associated with lower risk of developing diabetes. Compared with people who had the lowest composite biomarker score, the risk in people whose biomarker score was in the top 20% of the population was 50% lower. The researchers determined that every 66 grams per day increase in total fruit and vegetable intake (one standard deviation difference) was linked to a 25% lower risk of developing diabetes.
🧠 Higher dietary intake of spermidine may protect the brain in older individuals.
Researchers assessed dietary intake of spermidine (a polyamine that is relatively ubiquitous in plants) and Mediterranean diet adherence in 90 older adults with subjective cognitive decline and 47 healthy controls. They also performed MRI to determine brain volume and cortical thickness in these subjects. They found that higher spermidine intake was associated with larger hippocampal volume and greater cortical thickness in regions of the brain that are known to be vulnerable to Alzheimer’s pathology. Interestingly, statistical analyses revealed that dietary spermidine intake substantially mediated the relationship between Mediterranean diet adherence and structural brain measures, as has been previously suggested (the Mediterranean diet tends to be relatively high in spermidine). Good dietary sources of spermidine include certain vegetables, fruits, nuts, legumes, mushrooms, soybean products, and cereals.
😴 Less REM sleep is associated with higher risk of mortality.
Researchers analyzed data from the Outcomes of Sleep Disorders in Older Men (MrOS) Sleep Study, which included 2675 older men (mean age of 76.3 years), who were followed for a median of around 12 years. Their sleep architecture was assessed through polysomnography as well as wrist actigraphy. For every 5% reduction in REM sleep, risk of mortality increased by 13%, after adjusting for multiple demographic, sleep, and health covariates. The findings were replicated in a similar study (Wisconsin Sleep Cohort) which enrolled younger participants and a longer follow-up. A random forest model identified REM sleep as the most important sleep stage associated with survival.
Videos We Loved This Week
- George Zaidan: You’re Using Disinfectants Wrong. Here’s What You Actually Need to Do. Via Reactions (Produced by the American Chemical Society)
- Steve Lustig: How to make masks as effective as the N95 respirators using materials available to the public. Via Northeastern.
- Sigal Samuel & Sonia Shah: How humans are making pandemics more likely. Via Vox.
Products We Are Enjoying
Beet It Nitrate Sport Shots.
Beetroot is a rich source of nitrate, which relaxes the walls of the arteries when it transforms to nitric oxide. Wider blood vessels = better blood flow, and that makes it easier for blood to get to your muscles without increasing the workload of the heart. This seems to be good for endothelial function and blood pressure, and it has obvious advantages for physical performance as well, but it is sort of impractical to consume large amounts of nitrate-rich veggies before exercising. That’s what makes these shots useful - they efficiently deliver 400 mg of nitrate per serving in a portable 2.4 ounce shot. Incidentally, Beet It happens to be the product that many researchers, including Jonathan Burdette, have used to examine effects of dietary nitrate (check out our interview with him from last year).
