We all know that our bodies begin to “break down” as we age, but that change might be more sudden than we previously thought.
A Stanford Medicine study reveals that many of the body’s molecules and microorganisms dramatically increase or decrease in number at two specific times: ages 44 and 60.
The researchers assessed thousands of different molecules involved in aging in people aged 25 to 75, as well as their microbiomes – the bacteria, viruses and fungi that live inside us and on our skin.
They found that 81 percent of molecules and microbes do not change gradually and chronologically, but rather we go through two periods of rapid change over the course of our lives.
The number of molecules linked to cardiovascular disease showed significant changes at both ages, and those linked to immune function (our ability to fight off disease) changed in people around 60 years of age, revealed the research published in the journal Nature Aging.
A Stanford Medicine study reveals that many of the body’s molecules and microorganisms increase or decrease dramatically at two specific times: ages 44 and 60.
“We’re not changing gradually over time; there are some really dramatic changes,” said Michael Snyder, chair of the genetics department and senior author on the study.
“It turns out that the mid-1940s is a time of dramatic change, just like the early 1960s. And that’s true regardless of what kind of molecules you look at.”
The research team was inspired to look at the effects of molecular and microbial changes after observing that the risk of developing age-related diseases, such as Alzheimer’s disease and cardiovascular disease, increases sharply in middle age, rather than steadily.
Data from 108 people were used to better understand the biology of aging.
Participants’ blood and other biological samples were analyzed every few months for several years; the scientists tracked 135,000 age-related changes in different molecules, including RNA (which carries genetic information), proteins and metabolites, as well as the microbiome.
These major changes are likely to impact our health: the number of molecules linked to cardiovascular disease showed significant changes at both ages, and those linked to immune function changed in people around 60 years old.
They found that thousands of molecules and microbes experience changes in abundance, either increasing or decreasing.
About 81 percent of the molecules they studied were shown to have undergone extreme changes at specific ages.
When they looked for groups of molecules with the largest changes in quantity, they found that these transformations occurred most in two time periods: when people were around 40 years old and when they were around 60 years old.
The vast array of changes that occurred in the mid-1940s came as somewhat of a surprise to scientists.
At first, they assumed that menopause or perimenopause was driving big changes in the women in their study, skewing the entire group.
But they found that the change was also occurring in men in their 40s.
‘This suggests that while menopause or perimenopause may contribute to the changes seen in women in their 40s, there are likely to be other, more significant factors influencing these changes in both men and women.
“Identifying and studying these factors should be a priority for future research,” said Dr. Xiaotao Shen, a former Stanford Medicine postdoctoral researcher and now an assistant professor at Nanyang Technological University in Singapore.
In 40-year-olds, significant changes were observed in the amount of molecules related to alcohol, caffeine and lipid metabolism; cardiovascular disease; and skin and muscles.
In those aged 60 years, changes were related to carbohydrate and caffeine metabolism, immune regulation, kidney function, cardiovascular disease, and skin and muscles.
It’s possible that some of these changes may be related to lifestyle or behavioral factors that are concentrated in these age groups, Dr. Snyder said.
For example, a dysfunction in alcohol metabolism could result from an increase in alcohol consumption in the mid-40s, an often stressful period of life.
The team plans to explore the drivers of these clusters of changes.
But the findings suggest that people should pay attention to their health between ages 40 and 60, the researchers said.
This could involve increasing exercise to protect the heart and maintain muscle mass, or decreasing alcohol consumption.
“I strongly believe that we should try to adjust our lifestyle while we are still healthy,” Dr. Snyder said.
