Newsletter #046: How some factors affect cardiovascular disease 🫀
Welcome to the latest edition of the humanOS newsletter! Here is where we share our work, and the various studies and media that captured our attention this week. 🤓
This Week’s Research Highlights
😴 It’s not just how much you sleep - sleep timing may also play an important role in cardiovascular risk.
Researchers examined data from nearly 2000 subjects who did not have cardiovascular disease at the start of the study. Participants wore devices on their wrists that measured their sleep and activity for periods of 7 days and were followed for an average of four years. After adjusting for various factors, the researchers found that people whose night-to-night sleep length during a seven-day period varied by more than two hours on average were 2.2 times more likely to have a cardiovascular event than people whose sleep length varied by an hour or less. The time at which they fell asleep each night was also important - those with a bedtime that varied by more than 90 minutes had double to risk of a cardiovascular event, compared to individuals who went to bed within the same 30-min window each night.
Researchers measured levels of phthalates and their metabolites in urine collected from women during late pregnancy, then subsequently from their children at 3, 5, and 7 years of age. Then, the Bruininks-Oseretsky Test of Motor Proficiency short form (BOT-2), a screening test for motor problems, was administered to the children when they reached age of eleven. High exposure to phthalates was found to be associated with poorer motor function; almost one-third of the children in the study had below-average motor skills. Phthalates are widely used in personal care products like moisturizers and makeup, as well as plastic containers and children's toys.
Researchers analyzed nine eligible studies, providing data from 5,390,591 women and 101,424 cardiovascular events.. Compared with those who did not have gestational diabetes, women with gestational diabetes had a doubled risk of future cardiovascular events. Increased risk remained even if they did not go on to develop type 2 diabetes, and this was evident within the first decade after pregnancy.
Researchers tested muscular strength in 4681 adults (without type 2 diabetes at baseline) between 1981 and 2006, using leg press and bench press. They divided subjects into three groups (lower, middle, and upper) based on muscular performance. Participants who met the middle level of muscular strength had a 32% reduced risk of developing type 2 diabetes, compared with those in a lower level of strength (higher levels of muscle strength did not provide additional protection). Currently, only about 20% of Americans meet guidelines for resistance training (just two days per week), so clearly there’s plenty of room for improvement at the population level!
Videos We Loved This Week
- Gary Taubes & Stephan Guyenet: Joe Rogan Experience #1267. Via JRE.
- Alyssa Crittenden: Current Hunter-Gatherer Diets. Via CARTA.
- Jeffrey Friedman: Leptin and the neural circuit regulation food intake and glucose metabolism. Via NIH Videocast.
Products We Are Enjoying
Ginny says: I make a point to eat about one or two Brazil nuts every day. How come? Well, just one Brazil nut contains about 95 micrograms of selenium - which is an astounding 137% of the Daily Value! Consumption of Brazil nuts has been shown to be at least as effective as taking a similar dose of selenium in supplemental form. But they may have other benefits as well. This weird study, for instance, found that consuming just a single dose of 20 or 50 grams of Brazil nuts rapidly and substantially improved the lipid profile (LDL-C dropped by around 20 mg/dL). A similar study found a lasting decrease in inflammatory markers, including serum IL-1, IL-6, TNF-α, and IFN-γ. If you’re only consuming a couple of nuts per day, like me, this one-pound bag is a sweet deal, and should keep you for several months. You may not want to go crazy with them, in any case, at least not on a routine basis. The safe upper limit for selenium is 400 mcg daily, which you can easily exceed with 28 grams (or six kernels) of Brazil nuts.