Newsletter #051: Antagonistic pleiotropy, living longer, and cashew queso 🫀
Hello Friends!
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
🧬 Poverty leaves a mark on nearly 10% of the genes in the human genome.
Researchers assayed DNA methylation in leukocytes from 489 participants in the Cebu Longitudinal Health and Nutrition Survey. Socioeconomic status was measured in infancy, childhood, and adulthood. Genome-wide analysis revealed that lower socioeconomic status was associated with levels of DNA methylation at more than 2500 sites across more than 1500 genes. Functional enrichment analysis identified an over-representation of biological pathways related to immune function, skeletal development, and the development of the nervous system.
♀ Morning circadian misalignment is associated with insulin resistance in girls with the polycystic ovarian syndrome.
Researchers compared obese adolescent girls with PCOS (n=59) and without PCOS (n=33). They measured sleep duration, sleep timing, dim light salivary melatonin, and various other hormones. Girls with PCOS had later clock hours of melatonin offset, later melatonin offset relative to sleep timing, and longer duration of melatonin secretion. Later melatonin offset after wake time was associated with higher serum free testosterone and worse insulin sensitivity in both groups.
🍅 Tomatoes may help keep your liver healthy.
Mice were exposed to liver carcinogens in infancy, then fed a high-fat diet either with or without tomato powder rich in lycopene (the dose was roughly equivalent to a human eating 2-3 tomatoes or one serving of tomato sauce daily). The researchers found that mice consuming the tomato powder experienced reduced fatty liver disease, inflammation, and cancer. The experimental group also showed increased richness and diversity of beneficial microbiota. Notably, the powder was more effective than the same dose of purified lycopene for preventing liver cancer - suggesting that whole tomatoes may have unique beneficial compounds outside of just lycopene.
🏃🏾 Tiny amounts of physical activity may have big longevity benefits.
Researchers analyzed data from the National Health Interview Surveys (1997-2008), linked to the National Death Index records through the end of 2011. Compared to inactive individuals, those who performed non-vigorous, leisurely activities (like gardening, walking, or dancing) for just 10-60 min per week had an 18% lower risk of all-cause mortality. Individuals who performed at least 150 minutes per week of physical activity enjoyed a 34% reduced risk of all-cause mortality over the course of the study, and there was a larger reduction for vigorous exercise versus that of moderate intensity.
💊 Glycine supplementation extends the lifespan of male and female mice.
Researchers fed mice a diet of 8% glycine. Elevated glycine led to a small (4-6%) but statistically significant increase in lifespan, as well as an increase in maximum lifespan. The researchers suggest that high levels of glycine may depress methionine levels, thus mimicking the benefits associated with a diet low in methionine.
Podcasts We Loved This Week
- Matthew Walker: Heart disease, cancer, sexual function, and the causes of sleep disruption (and tips to correct it). Via the Peter Attia Drive podcast.
- Eileen Crimmins: Study shows people aging more slowly than two decades ago. Via the Live Long and Master Aging (LLAMA) Podcast.
- Jorg Fachner, Catherine Carr, & Alex Street: Can Music be Medicine? Via Naked Neuroscience.
Products We Are Enjoying
Trader Joe’s Cashew Fiesta Dip.
Ginny says: This stuff is amazing. 😍 It is actually a really simple product (ingredients are cashews, potatoes, carrots, onions, and spices) but very tasty and versatile. I like to put it on baked potatoes or yams, or you can use it as a dip (it’s definitely best warm). Pretty healthy too - 30 kcal per 24-gram serving.
And for you keto folks out there, it has zero net carbs. If you are looking for a reasonably healthy, dairy-free queso, I would highly recommend marching over to your local Trader Joe’s and picking some up. (If you aren’t near a Trader Joe’s, this would likely be pretty easy to replicate at home, just using the primary ingredients and a high-powered blender.)
New humanOS Content
Why do we age? The fundamental causes of aging at the molecular level are relatively well established, and we have explored them on humanOS Radio before. But the question of why aging happens in the first place is a more challenging one, and one which has bedeviled evolutionary biologists and philosophers for years.
You might think, intuitively, that the process of natural selection would gradually eliminate senescence. Aging increases mortality. And an organism that experiences impaired function and ultimately dies would not be able to produce as many offspring as one that was able to live (and to reproduce) indefinitely, or at least for a much longer timespan, right? Yet aging is very commonly observed. Why is that?
Natural selection is strongest in early life. This makes sense - the natural environment is full of predators, diseases, and other perils that often kill organisms when they are young and vulnerable. Consequently, genes and pathways that enhance survival and reproduction in early life are likely to be favored - even if they come at the cost of problems later in life, when selection is comparatively weak. But is aging inevitable? Or can it be slowed, postponed...or stopped altogether?
In this installment of humanOS, Dan talks with Michael Rose. Dr. Rose is a prolific biologist whose research into the evolution of aging has effectively transformed that field. Rose’s laboratory has been exploring the evolution of aging for nearly forty years, through artificial selection experiments in fruit flies. In what was perhaps his most famous experiment, Rose allowed flies to reproduce successfully only if they laid their eggs very late in life. He discarded the eggs of any flies that laid eggs before they reached fifty days of age (that’s really old for these flies). Over a few generations, this population of flies evolved longer lifespans. Why might this be? Remember that natural selection is strongest early in life, and becomes weak later on. In theory, if adults reproduce when they are older, natural selection is apt to favor genes that enhance resilience (and reproduction) later into the lifespan.
Dr. Rose's research into aging has also drawn him to some interesting (and possibly controversial) notions about evolutionary changes in the human diet, and how our age may influence how adapted we are to modern agricultural foods. To learn what that means, and its potential implications, check out the interview!