許多人都把中年發福歸咎於新陳代謝變慢，然而新研究發現，中年人的新陳代謝速度和年輕人無異，60歲後新陳代謝才開始減速。也許，中年發福只是吃得太多，動得太少。
[Photo/Pexels]
Middle-aged spread cannot be blamed on a waning metabolism, according to an unprecedented analysis of the body's energy use.
一項史無前例的新陳代謝研究指出，不能將中年發福歸咎於新陳代謝變慢。
The study, of 6,400 people, from eight days old up to age 95, in 29 countries, suggests the metabolism remains "rock solid" throughout mid-life.
這項涵蓋了29個國家6400人的研究顯示，人在中年時期的新陳代謝一直“穩如磐石”。研究物件中，最小的剛出生8天，最高齡的已經95歲。
It peaks at the age of one, is stable from 20 to 60 and then inexorably declines.
新陳代謝在1歲時達到頂峰，20歲到60歲期間保持穩定水平，60歲後開始不可阻擋地變慢。
The study, published in the journal Science, found four phases of metabolic life:
這項發表在《科學》期刊上的研究發現，人的一生中新陳代謝可分為四個階段：
1. birth to age one, when the metabolism shifts from being the same as the mother's to a lifetime high 50% above that of adults
第一階段：出生到1歲。新陳代謝速度最初和母親一致，後來達到一生中的最高水平，比成人高出50%。
2. a gentle slowdown until the age of 20, with no spike during all the changes of puberty
第二階段：1歲到20歲。新陳代謝逐漸變慢，整個青春期都沒有明顯波動。
3. no change at all between the ages of 20 and 60
第三階段：20歲到60歲。新陳代謝毫無變化。
4. a permanent decline, with yearly falls that, by 90, leave metabolism 26% lower than in mid-life
第四階段：60歲後。新陳代謝速度逐年下降，90歲時新陳代謝速度比中年時期慢26%。
Screenshot from BBC
"It is a picture we've never really seen before and there is a lot of surprises in it," one of the researchers, Prof John Speakman, from the University of Aberdeen, said.
參與該研究的阿伯丁大學教授約翰·斯皮克曼稱：“這是我們從未預料到的，發現了不少驚人的結果。”
"The most surprising thing for me is there is no change throughout adulthood - if you are experiencing mid-life spread you can no longer blame it on a declining metabolic rate."
“最讓我驚訝的是，成年後新陳代謝一直沒有變化。如果你正在經歷中年發福，你再也不能把這歸咎於新陳代謝變慢。”
People's metabolism was measured using doubly labelled water.
研究人員用雙標記水來測量人們的新陳代謝速度。
Made from heavier forms of the hydrogen and oxygen atoms that make up water, this can be tracked as it leaves the body.
重水分子中被標記的氫原子和氧原子可以在離開身體後被追蹤到。
But doubly labelled water is incredibly expensive, so it took researchers working together across 29 countries to gather data on 6,400 people.
但是雙標記水很昂貴，所以該研究透過29個國家科研人員的通力協作才收集到6400人的資訊。
The researchers said fully understanding the shifting metabolism could have implications in medicine.
研究人員表示，充分了解新陳代謝的變化對於醫藥學可能有意義。
Prof Herman Pontzer from Duke University said it could help reveal whether cancers spread differently as the metabolism changes and if drug doses could be adjusted during different phases.
杜克大學的赫爾曼·龐策教授稱，這將有助於揭示癌症的擴散速度是否會隨著新陳代謝的變化而有所不同，以及不同年齡段的用藥量是否應進行調整。
[Photo/Pexels]
And there is even discussion about whether drugs that modify the metabolism could slow diseases of old age.
還有人甚至在討論調節新陳代謝的藥物是否能推遲老年病的到來。
Drs Rozalyn Anderson and Timothy Rhoads, from the University of Wisconsin, said the "unprecedented" study had already led to "important new insights into human metabolism".
威斯康星大學的羅扎林·安德森博士和蒂莫西·羅茲博士稱，這一“史無前例的”研究帶來了“關於人類新陳代謝的重大啟示”。
And it "cannot be a coincidence" diseases of old age kicked in as the metabolism fell.
此外，老年病在新陳代謝變慢時到來“絕非偶然”。
Prof Tom Sanders, from King's College London, said: "Interestingly, they found very little differences in total energy expenditure between early adult life and middle age - a time when most adults in developed countries put on weight.
倫敦國王學院的湯姆·桑德斯教授稱：“有趣的是，研究人員發現，青年和中年時期的新陳代謝速度差異很小，而發達國家的大多數成年人都是在中年時期發胖的。”
"These findings would support the view that the obesity epidemic is fuelled by excess food energy intake and not a decline in energy expenditure."
“這些研究結果支援了一個觀點，就是中年發福是因為食物攝取過量而不是新陳代謝變慢。”
英文來源：BBC
翻譯&編輯：丹妮
來源：中國日報網
