Metabolism Slowing Is Not A Problem Until After Age 60
Metabolism is every drop of chemistry needed to keep the body going. BBC health and science correspondent James Gallagher reports that a 29 country study of 6,400 people, from eight days old up to age 95, suggests that metabolism remains “rock solid” throughout mid-life peaking at the age of one, remaining stable from 20 to 60, and then declining dramatically afterwards.
Researchers tweaked their measurements, adjusting for body size, to compare people’s metabolism “pound for pound” for the bigger the body – whether that is ripped muscles or too much belly fat – the more energy it will take to run. Metabolism was measured using doubly labelled water (made from heavier forms of hydrogen and oxygen atoms) that can be tracked as it leaves the body. Doubly labelled water is incredibly expensive, so it took researchers working together across 29 countries to gather data on 6,400 people.
The study, published in the journal Science, found four phases of metabolic life:
- From birth to age one, it shifts from being the same as the mother’s to a lifetime high 50% above that of adults
- There is a gentle slowdown until the age of 20, with no spike during puberty
- There is no change at all between the ages of 20 and 60
- After 60, there’s a permanent decline, with yearly falls that, by 90, leaves it 26% lower than in mid-life
Surprisingly, there was no metabolic surge during either puberty or pregnancy and no slowdown around menopause. High metabolism in the first years of life also emphasize how important those years are in development and why childhood malnutrition can have lifelong consequences.
Researchers say fully understanding shifting metabolism could have implications in medicine as it could help reveal whether cancers spread differently as metabolism changes, and if drug doses could or should be adjusted during different phases. There is even discussion about whether drugs that modify metabolism could slow diseases of old age which overwhelmingly become prevalent as it slows.