Study finds dramatic change in molecule, microbes at post-40, affecting whole metabolism

New Delhi: A new study has found that in mid-40s and early 60s, one experiences a dramatic surge or fall in molecules and microbes, significantly affecting heart and immune function, muscles, along with how their body handles alcohol and coffee.

Researchers tracked changes due to ageing in more than 1,35,000 different molecules and microbes in people aged 25 to 75 and found that molecule and microbe counts did not shift gradually over the years.

Risks of age-related diseases such as Alzheimer's disease and cardiovascular conditions are known to rise sharply in older age, compared to a gradual increase for those aged under 60.

Rather, we undergo two periods of rapid change during our life span, averaging around age 44 and age 60, the researchers at Stanford University, US, said. The findings are published in the journal Nature Aging.

"We're not just changing gradually over time; there are some really dramatic changes. It turns out the mid-40s is a time of dramatic change, as is the early 60s. And that's true no matter what class of molecules you look at," said senior author Michael Snyder, chair of genetics at Stanford University.

Among people in their 40s, the researchers noted changes in count of molecules involved in metabolising alcohol, caffeine and lipids (fats), along with those related to heart disease, skin and muscles.

Among people in their 60s, changes were related to carbohydrate and caffeine metabolism, immune and kidney function, along with those in count of molecules linked to cardiovascular disease, and skin and muscles.

From blood and other biological samples taken from 108 participants every few months over several years, the authors looked at different molecules, such as RNA and proteins, as well as shifts in their microbiomes, including the bacteria, viruses and fungi living in the body. A total of nearly 250 billion distinct data points were analysed.

"Using this approach, 81.03 per cent of molecules exhibited changes in at least one age stage compared to the baseline," the authors wrote.

They said that while studies have looked at how different molecules increase or decrease as we age and how biological age differs from chronological age, few have looked at the rate at which we biologically age.

That so many dramatic changes happen in the early 60s is perhaps not surprising, as many age-related disease risks and other age-related phenomena are known to increase at that point in life, Snyder said.

However, the cluster of changes observed in the participants during their mid-40s was surprising to the team, they said.

While the researchers initially assumed these changes to be driven in menopausal or post-menopausal women, upon breaking the study group by gender, the changes were seen to be happening in mid-40s men as well.

"This suggests that while menopause or perimenopause may contribute to the changes observed in women in their mid-40s, there are likely 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 first author Xiaotao Shen, an assistant professor at Nanyang Technological University, Singapore.

The age-related cluster of changes seen point to the need for people to pay attention to their health, especially in their 40s and 60s, the researchers said.

This could look like increasing exercise to protect your heart and maintain muscle mass at both ages or decreasing alcohol consumption in 40s as the ability to metabolise alcohol slows, they said.