Instead of aging gradually, in a linear fashion, our bodies appear to undergo two major biomolecular shifts, at around the average age of 44 and again at 60, that could have a major impact on our health.
By assessing more than 135,000 different molecules and microbes from individuals ages 25 to 75, researchers found that human bodies seem to age in two distinct bursts during our lifespans.
“It turns out the mid-forties is a time of dramatic change, as is the early sixties. And that’s true no matter what class of molecules you look at,” says the senior study author,Michael Snyder, PhD, a professor of genetics at Stanford Medicine in California. “During both these periods, lots of shifts are happening. In the sixties, the shifts are particularly dramatic.”
Dr. Snyder adds that the findings could provide insights into the molecular mechanisms driving age-related diseases, which could lead to the development of early diagnosis and prevention strategies.
Bodily Transformations Occur in Clusters
For the analysis, researchers took biological samples from 108 subjects every three to six months over an average tracking period of 1.7 years and a maximum period of 6.8 years. Participants had diverse ethnic backgrounds, and just over half were female.
In total, the scientists collected more than 5,400 blood, stool, skin swab, oral swab, and nasal swab samples and examined them for their molecular content, which included RNA (a type of genetic material), proteins, and metabolites (substances produced during digestion or other bodily chemical processes). The scientists then tracked any age-related changes in more than 135,000 different molecules and microbes.
Over the course of the study, they found that just over 80 percent of all the molecules showed nonlinear fluctuations in number (either increasing or decreasing) — meaning they changed more at certain ages than at other times — specifically when people were in their forties and sixties.
“The data is surprising,” says James White, PhD, an assistant professor in the departments of medicine and cell biology at Duke University School of Medicine and the Duke Aging Center. “It is generally thought that aging manifests itself gradually and progressively, but these findings suggest this may not be the case.”
Previous research has supported the assertion that the biological aging process isn’t necessarily incremental, and that it appears to accelerate periodically.
An analysis published in Nature Medicine in 2019, which examined nearly 3,000 plasma proteins from 4,263 adults ranging in age from 18 to 95, revealed that the greatest bursts of change in these molecules came at ages 34, 60, and 78.
How Molecular Shifts May Affect Health
In this new study, researchers observed similar molecular changes at both age periods related to cardiovascular disease, skin and muscle aging, and the metabolizing of caffeine.
Researchers did note differences between the ages. Individuals in their forties had distinct shifts in the number of molecules connected to alcohol and fat metabolism, while those in their sixties also experienced changes related to carbohydrate metabolism, immune regulation, and kidney function.
Physical decline starting in the sixties is to be expected, according to Snyder. The aging immune system, for example, loses the ability to protect against infections and cancer, and the prevalence of heart disease markedly rises.
Snyder, however, did not anticipate such significant changes in people in their forties.
“Perhaps people at this age are becoming more sedentary and their poor diets build up to a point where things fall apart,” he says.
Dr. White, who was not involved in the new research, adds that biological shifts in the forties may be particularly linked to lifestyle challenges.
“Early middle age is associated with busy family schedules, high stress at work, midlife crisis, and weight gain, and divorce rates peak at this age,” he says. “It’s a time in life when stress is high and self-care is low.”
The study authors suggest that these midlife stressors could lead to an uptick in alcohol consumption, which in turn leads to problems with metabolizing alcohol and a host of other harmful health effects.
Take Steps to Fight Decline
While aging is inevitable, people can take action that may curb their molecular decline.
“This study suggests nuances on how we go about prevention, but we already know major factors that lead to lower [health] risks include a diet rich in fruits and vegetables, avoiding weight gain, controlling diabetes and hypertension, not smoking, and maintaining physical activity,” says Josef Coresh, MD,the founding director of NYU Langone’s Optimal Aging Institute in New York City, who was not involved in the research.
Snyder further urges 40-somethings to pay attention to their cholesterol levels, improve muscle mass through exercise, and decrease alcohol consumption as the metabolism slows. He suggests that individuals in their sixties look into increasing their intake of anti-inflammatory foods (such as garlic) and antioxidants (such as vitamins C and E) to help stabilize molecules.
“I’m a big believer that we should try to adjust our lifestyles while we’re still healthy,” he says.
