Newsletter #234

Hey friends, this week we have kind of a grab bag of juicy new studies. This research provides some insight into how physical activity strengthens your body and mind, as well as one of the most well-controlled experiments examining the effects of meal timing that I have ever seen.

🧠 Physical activity appears to be the most effective intervention currently available for reversing dysregulated gene expression in Alzheimer’s disease.

🏀 Playing multi-directional sports (like basketball and soccer) as a child builds stronger bones that are less prone to injury in adulthood, compared to specializing in running or other unidirectional activities.

⏰ Eating meals later increases hunger, modifies hormones that modulate appetite, decreases energy expenditure, and alters fat tissue gene expression in a way that favors lipid storage.

Effective treatments for Alzheimer’s disease are notoriously elusive, with one of the highest failure rates in drug development. To try to identify promising avenues for future interventions, researchers at the University of Wisconsin examined 22 datasets on human Alzheimer’s disease gene expression and captured consistent patterns of gene expression dysregulation across brain regions that appear in the disease. They then matched these expression profiles to datasets for a vast array of potential treatments. Out of more than 250 evaluated treatments, physical exercise emerged as the top theoretical treatment, for its ability to reverse expression of hundreds of genes that are dysregulated in Alzheimer’s. Ranked second behind exercise was the antidepressant fluoxetine (Prozac), and third was curcumin. Interestingly, one of the authors previously created a similar gene expression portrait for depression and also found exercise to be the top theoretical treatment, though the extent of gene expression reversal was not nearly as profound as it was for Alzheimer’s.

Researchers at Indiana University looked at female collegiate cross country runners, and divided them into two groups based on their early training history: 1) those who had only trained/competed in running, swimming or cycling, and 2) those who had prior training/competing in soccer or basketball in addition to their running. The researchers then used high-resolution imaging to assess the structure and strength of the bones in the shin and feet of these women, and compared them. They found that the athletes who had a history of playing soccer or basketball had 10-20% stronger bones than those who had specialized in unidirectional sports. Lead author Stuart Warden said, “Our research shows that the runners who played multidirectional sports when younger had stronger bones as collegiate athletes, which puts them at less risk for bone stress injuries including stress fractures.”

Researchers at Brigham and Women’s Hospital recruited 16 patients whose BMI was in the overweight or obese range, and admitted them to the lab on two separate occasions, which were separated by a washout period of 3-12 weeks. During each stay, they spent six days in the laboratory, where their nutrient intake, physical activity, sleep, and light exposure were carefully monitored and controlled. The one major difference between these lab stays was food timing: in one protocol, participants ate their three meals earlier (first meal one hour after waking and last meal about 6.5f hours before bedtime) and in the other protocol, they ate identical meals later in the day (first meal around 5 hours after waking and last meal about 2.5 hours before bedtime). When the participants ate later, waking levels of leptin, a hormone that signals satiety, were 16% lower and they reported increased hunger, compared to when they ate earlier. Their energy expenditure was also lower in the late eating condition: participants burned ~60 fewer calories per waking day (–5% less).

Marcus Terentius Varro was and is regarded as one of the greatest scholars of ancient Rome. In 36 BC, he wrote a voluminous work on agriculture called Res rusticae, in which he alludes to microscopic organisms causing disease:

"Precautions must also be taken in neighborhood swamps . . . because certain minute creatures [animalia minuta] grow there which cannot be seen by the eye, which float in the air and enter the body through the mouth and nose and there cause serious diseases.”

Glycine, in the right dose, increases blood flow to the extremities, which in turn elicits a drop in core body temperature (for a more detailed explanation of how thermoregulation influences sleep, check out this blog). Pretty cool. Glycine may do other good stuff too - for instance, a rodent study showed that glycine supplementation extended lifespan. Studies typically use around three grams, which is why powder is the economical choice here. Fortunately, it happens to taste sweet (hence the name), so it’s pretty easy to add to a beverage before bed.

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

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