People go through two periods of dramatic change during their lives, around the age of 44 and then at 60, research suggests.
The small study shows that many of the molecules and micro-organisms in the body dramatically rise or fall in number during our forties and sixties.
When assessing thousands of different molecules in people from the ages of 25 to 75, as well as their microbiomes – the bacteria, viruses and fungi that live inside us and on our skin – scientists found that their numbers do not shift in a gradual, chronological fashion.
Michael Snyder, chairman of genetics at Stanford University in the US, and the study’s senior author, said: “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.”
In people in their forties, significant changes were seen in the number of molecules related to alcohol, caffeine and fat metabolism, heart disease and skin and muscle.
In those in their sixties, changes were related to carbohydrate and caffeine metabolism, immune regulation, kidney function, heart disease and skin and muscle.
The researchers suggest some of these changes could be tied to lifestyle or behaviour factors that cluster at these age groups, rather than being driven by biological factors.
For example, dysfunction in alcohol metabolism could result from an uptick in alcohol consumption in people’s mid-forties, which is often a stressful period of life.
But whatever causes these periods of change, the existence of them indicates the need for people to pay attention to their health during these times, the researchers said.
That could involve doing more exercise to protect the heart and maintain muscle mass at both ages, or drinking less alcohol in their forties as the ability to process alcohol slows.
In the study, published in the journal Nature Ageing, the researchers used data from 108 people they have been following to better understand the biology of ageing.
The large cluster of changes in the mid-forties was surprising to the scientists.
At first they thought that menopause or perimenopause was driving large changes in the women, but when they broke out the study group by sex, they found the shift was happening in men in their mid-forties, too.
“This suggests that while menopause or perimenopause may contribute to the changes observed in women in their mid-forties, 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 Xiaotao Shen, a former Stanford Medicine postdoctoral scholar, and first author of the study.
– with PA
Did you notice any physical changes in your 40s or 60s? How well do you think you’re ageing? Let us know in the comments section below.
Also read: Discrimination may accelerate ageing
