As I approached my forties, several older friends were already warning me that health declines after the age of 40... A new study may well prove them right.
Researchers from Stanford University in the United States have analyzed the consequences of aging on a large number of signaling pathways in the body, showing that the greatest changes occurred during the forties and after the age of 60. Two times in life marked by lifestyle changes, which could contribute to these accelerations of the aging processTheir discovery was published on August 14, 2024 in the journal Nature Aging.
The effects of age on our biology are not linear
To reach this conclusion, the researchers analyzed a range of biological samples from 108 participants, including blood, fecal samples, and swabs of the skin, nose and mouth, collected every 3 to 6 months over several years (from 1 to 6.8 years, with a median of 1.7 years).
Half of the participants were women, they were all in good health and were between 25 and 75 years old (with an average age of 56). Thanks to these thousands of biological samples, the researchers followed nearly 135,000 molecules or microbes of the microbiota, evaluating their fluctuations.
This device allowed them to demonstrate that approximately 11,000 of these molecules were associated with aging, their content changing according to age. First surprise: only a small minority (6.6%) of these molecules varied linearly with age.
These fluctuations occur at certain specific moments in life.
All other molecules fluctuated irregularly, however some had some profiles in common. For example, the rate of nearly 1500 of these molecules increased after the age of 65. This is particularly the case for molecules associated with cardiovascular or renal dysfunctions. This is also the case for blood glucose, for example, with higher blood sugar levels after the age of 65, and therefore a greater risk of type 2 diabetes.
Other molecules, on the contrary, decreased after the age of 60, such as those involved in the metabolism of caffeine. This suggests that our ability to tolerate this stimulant decreases sharply after the age of sixty. While molecules necessary for the metabolism of alcohol or lipids fell after the age of 40, suggesting a lesser ability to digest alcohol and fat after this age.
In general, the majority of the molecules studied fluctuated at two specific times, around 40 and 60 years of age. These two "waves" of aging involved a large number of processes, particularly those related to the aging of the skin and muscles, showing accelerated degradation at these two times.
Lifestyle changes may be partly responsible
Second surprise: These fluctuations at specific times were largely the same for men and women, and seemed independent, at least in part, of other factors such as menopause. Menopause certainly has an impact on aging, but our study found that most age-related changes occur in both men and women, " explains Michael Snyder, a geneticist at Stanford University and author of the study. I think these changes are more related to lifestyle, which changes a lot in the forties, when people generally become more sedentary. The same in the sixties, when we retire. Although biological changes, such as a deterioration of our immune system after the age of 60, probably play an important role too."
There would therefore be biological causes for these accelerations of aging, but not only that. All centenarians have three things in common: they have remained physically active to some extent, they eat relatively well, and they are well surrounded, showing that our behavior and lifestyle play a vital role., he emphasizes. Which is rather reassuring, because it means that we can take action to age better.”
For example, he recommends doing more physical activity in your forties and sixties, in order to maintain muscle mass and protect the cardiovascular system, as well as reducing alcohol consumption after the age of 40 since we have more difficulty metabolizing it from this age onwards.Currently, our healthy lifespan is about 10 years shorter than our life span, meaning that the majority of people spend their last decade in fight against health problems, he recalls. By improving our lifestyle, we could improve our health to be fit throughout life".
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