We all know that our bodies “deteriorate” as we age, but that change can happen more suddenly than we think.
A Stanford Medicine study found that the number of molecules and microorganisms in the body increases or decreases dramatically at two specific times: at age 44 and at age 60.
Researchers assessed thousands of different molecules involved in aging in people aged 25 to 75, as well as their microbiome — 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. Instead, we go through two periods of rapid change during our lives.
The number of molecules linked to cardiovascular disease showed significant changes at both ages, and molecules linked to immune function (our ability to fight disease) changed in people in their early 60s, according to the study, published in the journal Nature Aging.
A Stanford Medicine study found that many of the molecules and microorganisms in the body increase or decrease significantly in number at two specific times – ages 44 and 60.
“We’re not just changing gradually over time; there are really dramatic changes happening,” said Michael Snyder, chair of the department of genetics and lead author of the study.
“It turns out that the mid-1940s is a time of dramatic change, just like the early 1960s. And that’s true no matter what class of molecules you’re looking at.”
The research team was inspired to investigate the effects of molecular and microbial shifts after noticing that the risk of developing age-related conditions such as Alzheimer’s disease and cardiovascular disease increases dramatically rather than steadily in middle age.
Data from 108 individuals were used to better understand the biology of aging.
The participants’ blood and other biological samples were analyzed every few months for several years, with scientists tracking 135,000 age-related changes in various molecules, including RNA — which carries genetic information — proteins and metabolites, as well as the microbiome.
These major changes likely 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 in their early 60s.
They found that thousands of molecules and microbes undergo a shift in their abundance, either increasing or decreasing.
About 81 percent of the molecules they studied underwent extreme changes at specific ages.
When they looked for clusters of molecules with the greatest changes in abundance, they found that these transformations occurred most frequently in two time periods: when people were in their mid-40s and when they were in their early 60s.
The large amount of changes in the mid-1940s was somewhat surprising to scientists.
Initially, they assumed that menopause or perimenopause would cause major changes in the women in their study, thereby skewing the entire group.
But they found that the change also occurred in men in their mid-40s.
‘This suggests that while menopause or perimenopause may contribute to the changes seen in women in their mid-forties, there are likely other, more important 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 postdoctoral researcher at Stanford Medicine and now an assistant professor at Nanyang Technological University Singapore.
In people in their forties, significant changes were observed in the number of molecules related to alcohol, caffeine and lipid metabolism, cardiovascular disease, and skin and muscle.
In people in their 60s, changes were related to carbohydrate and caffeine metabolism, immune regulation, kidney function, cardiovascular disease, and skin and muscle.
According to Dr. Snyder, it’s possible that some of these changes are related to lifestyle or behavioral factors that occur in these age groups.
For example, impaired alcohol metabolism can result from increased alcohol consumption in people in their mid-40s, a period that is often stressful.
The team wants to investigate the causes of these change clusters.
But the findings suggest that people in their 40s and 60s need to pay attention to their health, the researchers said.
For example, this could mean exercising more to protect your heart and maintain your muscle mass, or reducing your alcohol consumption.
“I’m a big believer in making lifestyle changes while we’re still healthy,” Dr. Snyder said.