Dr. Cate Shanahan hits the Q&A hard, offering interesting commentary on a variety of topics, especially those relating to hormones and longevity markers. Cate explains how one's level of elastin is a major predictor of lifespan. Elastin is typically considered an important component of healthy skin. Losing elastin and collagen (a form of elastin that is also a major element of healthy skin) cause wrinkles, an obvious sign of aging. Elastin, however, is present in other cells such as those in joints and arteries. Losing elastin accelerates aging (arteries become stiffer and less resilient; joints become creakier and less fluid) and hastens demise. Across species, the typical half-life of elastin is a lifespan predictor. For example, the half-life of elastin in a dog is 10 years whereas it’s 75 years in humans.
 
One develops a lifetime supply of elastin by age 20, which makes childhood and teen years critical for obtaining the optimal nutrition to fully realize elastin production potential. Pro-inflammatory lifestyle habits have a destructive effect upon elastin. On the other hand, consuming glycosaminoglycans, as found in bone broth and meat on the bone, can have a positive effect on elastin by helping maintain its structure (glucosamine supplements have been reported to serve this purpose too, but they are not as potent or comprehensive as the elastin supporting compounds found in whole food sources).

A question comes in about hormone replacement therapy to combat aging and Cate comments about the proven effect of exogenous hormones to preserve elastin, which has distinct anti-aging effects. She also comments on its potential drawbacks, such as an elevation in triglycerides and blood pressure, as well as hot flashes from increased sensitivity to cortisol. Cate speculates that cheating nature will always have some repercussions to consider. While hormone manipulation could elevate peak performance potential, it could come with a consequent negative effect on longevity.