Newsletter #233

Hey y’all, hope everyone is doing well! This week we are tentatively debuting a more streamlined newsletter format. More of a research roundup than a deep dive.

Although I obviously love to dig into the details of various studies, I think this approach will be more efficient for you to consume. And frankly it more closely aligns with what we originally envisioned for the content when we decided to release the newsletter years ago.

Key takeaways for this week:

🍵 Tea may fight cognitive decline through its antioxidant and iron-chelating effects in the brain

🍫 Cocoa flavanols lower blood pressure and improve endothelial function in leg arteries (you might recall we talked about why that’s important in a past newsletter)

🛌🏻 Using a weighted blanket might enhance sleep by boosting melatonin secretion

🦠 Short sleep increases your risk of coming down with a cold or flu, but good sleep quality may offset this effect

Researchers analyzed data from 4820 individuals in China above the age of 55 who had undergone tests of cognitive function at four different intervals between 1997-2006 and who self-reported their tea-drinking habits. The researchers found that higher tea intake was linked to reduced cognitive decline, and more was better - drinking 4 or more cups per day was associated with 27-30% lower odds of poor memory and memory decline. When the team looked at the overall diet, they observed that high iron intake was associated with poorer cognition, but only in those who did not consume tea. We’ve known for a long time that tea interferes with absorption of nonheme iron, but this may not always be a bad thing given how brain iron accumulation has been implicated in neurodegenerative diseases.

Researchers at the University of Surrey recruited 11 healthy individuals and 11 with type 2 diabetes. On two separate days in random order, the subjects were given either 1350 mg of cocoa flavanols (CocoaVia) or placebo capsules. Before and two hours after each treatment, endothelial function was measured via ultrasound (flow-mediated dilation) in the brachial and femoral arteries. A single dose of cocoa flavanols resulted in significant improvements in both arteries at the 2-hour mark in both groups. Additionally, femoral artery blood flow and microvascular diameter increased in the feet, which is a particularly key concern for those with type 2 diabetes. Finally, the cocoa decreased systolic BP in both healthy subjects and those with type 2 diabetes (−7.2 ± 9.6 mmHg).

Researchers in Sweden recruited 26 young healthy participants and had them spend the night in the lab under carefully controlled conditions on two different occasions, in randomized order. On one night, they used a light blanket (~2.4% of body weight), and on another night they used a weighted blanket (~12% of body weight). Saliva samples were collected every twenty minutes between 10-11pm to assess effects of the blankets on various hormones. When using the weighted blanket, the 1-hour increase in salivary melatonin before lights out was ~32% higher. Underlying mechanisms remain unclear — we really need more research on weighted blankets — but anecdotally they seem pretty great.

Researchers in the UK assessed self-reported sleep in 1318 military recruits at the beginning and end of a 12-week training course. Perhaps unsurprisingly, about half of the recruits were characterized as sleep restricted upon commencing training, and these recruits were more than twice as likely to suffer an upper respiratory tract infection, compared to those whose sleep duration was maintained. However, when the researchers factored in the perceived sleep quality of these recruits, the association between sleep restriction and illness was eliminated. Those who reported poor sleep quality at the start and end of training had 3 times higher odds of developing URTI during the study.

In 1945, American physicist Percy Spencer was working on radar systems for Allied naval ships when he happened upon this discovery. The first food he decided to experiment with was (of course) popcorn kernels, which popped before his eyes.

However, it was a long time before microwave ovens were widely available. In 1947, the first commercially produced microwave was six feet tall and cost the equivalent of more than $60,000 in today’s money. Twenty years later, in 1967, the first counter-top sized microwave was made available for sale, costing $495 (equivalent to more than $4000 now).

Each scoop of this powder packs 500 mg of cocoa flavanols with only 10 calories. They also offer capsules if you prefer, but the powder is a little more cost-effective, and it’s not hard to use. I’ve added it to coffee successfully, and it also mixes well into smoothies and oatmeal. It also tastes surprisingly good, considering how concentrated it is - very rich chocolatey flavor and not too bitter.

Thanks for reading, enjoy the weekend, and we will see y'all next week!

https://mailchi.mp/humanos.me/newsletter-233