Altogether, the samples formed some 246 billion data points (biomarkers) for the team to measure across the 50-year age span of the participants. “We were looking for when changes and disruptions most commonly occurred at a molecular and biochemical level,” explains Michael Snyder, a co-author of the study and the chair of the department of genetics at Stanford Medicine.
The results show that 81 percent of the molecules didn’t change continuously—as would be expected with linear aging—but instead transformed significantly around ages 44 and 60.
At age 44, some of the observed changes occurred in cells affecting metabolism—which could explain why we have a harder time absorbing and processing caffeine and alcohol as we get older; fatty tissue proteins—which could explain higher cholesterol levels and unexpected weight gain in middle age; and connective tissue proteins associated with skin and muscle structure—which could explain why skin starts to sag, wrinkles appear, and “why people have more issues related to muscle strain and injuries,” explains Snyder.
