Scientists have now discovered, in a ground-breaking study published in the journal Nature Aging, that there are two major waves of aging in the human body: one during the mid-40s, and another at age 60. The discovery has changed the conventional belief that aging is a slow and progressive process but has pointed out that specific time frames show rapid transitions in the body’s functions.
A research team at Stanford School of Medicine led a study that tracked 108 people from ages 25 through 75 years for several years. From thousands of measurements of metabolites, lipids, and immune features in blood and stool, and of microbes in stool, skin, nose, and mouth, the analysis reported in a recent paper revealed dramatic physiological changes that occur during a person’s mid-40s and early 60s, coinciding with major life events. Shifts during this phase include how the body is processing lipids and carbohydrates, immune function, and a shift in muscle health.
“We’re not just changing gradually over time. There are some really dramatic changes,” said Michael Snyder, a geneticist and director of the Center for Genomics and Personalized Medicine at Stanford. He is the senior author of the study. He noted that independent of the class of molecules analyzed, the mid-40s and early 60s were periods of real upheaval.
The first wave of changes, occurring around age 44, involved molecules related to cardiovascular disease and the ability to metabolize caffeine, alcohol, and lipids. A second wave, at about age 60, involved those tied to immune regulation, carbohydrate metabolism, and kidney function. Molecules related to skin and muscle aging changed in both waves.
Although the concept of this mid-40s aging spike had pointed to a perimenopausal change in women, it turned out from the data that similar kinds of changes were occurring in men. Hence, it shows other key factors are involved. Dr. Xiaotao Shen, a former Stanford postdoctoral scholar, now based at Nanyang Technological University Singapore, shared that while menopause could be creating part of the change seen in women, other factors are probably influencing these changes in both genders.
The findings might also partly explain why some age-related health issues, such as cardiovascular disease and musculoskeletal problems, have peak incidences at particular ages. For example, the change in alcohol metabolism seen during the mid-40s may be followed by consumption when people go through this stressful time of life.
Knowing how to head off these bursts of aging might give researchers a way to design more targeted interventions, counseled Professor Snyder. People in their 40s should “really start paying attention” to their levels of lipids and begin lifestyle modifications, such as more exercise and a good diet, to counteract the metabolic shift. “I’m a big believer that we should try to adjust our lifestyles while we’re still healthy,” Snyder said.
While it brings new insight into the aging process, more research is needed to understand the full implications of the findings, experts say. It gives new details about detailed molecular changes but requires further study to determine their contribution to long-term health.
It brings out the message that early intervention and change of lifestyle are important in the attainment of old age with minimal complications and good health. By understanding this complex process, this study can lead to more personalized and, hence, effective health strategies.