研究發現「中年發福」或跟遺傳有關

U.S. researchers said Tuesday that they have identified an enzyme that may play a central role in the development of obesity in mid-life.

本周二，美國研究者表示稱，他們發現了一種可能在中年人發福現象中起到核心作用的酶。

In two groups of mice being fed high-fat foods, those who received an inhibitor that blocked the enzyme had a 40 percent decrease in weight gain compared with those that did not receive the drug.

在兩組餵食高脂肪食物的小白鼠中，一組被使用了阻斷這種酶的抑製劑，結果發現相比於另一組沒有用藥的小白鼠，這組小白鼠體重增加量要少40%。

The findings, published in the U.S. journal Cell Metabolism, could upend current notions about why people gain weight as they age, and could one day lead to more effective weight-loss medications.

該研究結果刊載於美國雜誌《細胞新陳代謝(Cell Metabolism)》，可能會顛覆人們對於隨著年齡增長身體發福這一現象的認知，或許有一天能夠幫助研製出更有效的減肥藥。

"Our society attributes the weight gain and lack of exercise at mid-life (approximately 30 to 60 years) primarily to poor lifestyle choices and lack of will power, but this study shows that there is a genetic program driven by an overactive enzyme that promotes weight gain and loss of exercise capacity at mid-life," said lead study author Jay H. Chung, head of the Laboratory of Obesity and Aging Research at the National Heart, Lung, and Blood Institute (NHLBI), part of the U.S. National Institutes of Health.

傑伊·常是這項研究的主要作者，他是美國心肺血液研究所(該研究所是美國國家衛生研究院的一部分)下屬肥胖和衰老研究室主任，他說道：「我們社會一般認為中年人(30到60歲)體重增加和缺乏鍛煉是因為不良的生活方式和缺乏意志力的原因，但是這項研究表明也存在著遺傳因素——一種過度活躍的酶會使得人們中年時體重增加、喪失運動能力。」

Researchers have known for years that losing weight and maintaining the capacity to exercise tend to get harder beginning between ages 30 to 40 -- the start of mid-life.

多年來研究人員發現，在剛步入中年時(30到40歲)減肥和保持運動能力往往會變得越來越困難。

In fact, it』s estimated that an average adult in America gains 30 pounds (13.6 kilograms) from age 20 to 50, even though food intake usually decreases during this period.

事實上據估計，美國成年人在20到50歲期間會平均增重30磅(約合13.6公斤)——即使這一年齡段人的進食量通常會減少。

Scientists have developed new therapies for obesity, including fat-fighting pills, but many of those therapies have failed.

科學家們也已經開發出了治療肥胖的新方法，包括減肥藥，但是許多治療方法都失敗了。

Chung and his associates searched for biochemical changes that occurred in middle-aged animals that are equivalent to 45 years in humans.

Chung和他的同事們在中年動物(相當於45歲的人類)的身體上尋找生物學變化。

They found that an enzyme called DNA-dependent protein kinase, or DNA-PK, increases in activity with age.

他們發現隨著年齡的增長，一種被稱之為DNA依賴蛋白激酶(DNA-dependent protein kinase)的物質活性與日俱增。

Further work showed that DNA-PK promotes conversion of nutrients to fat and decreases the number of mitochondria, tiny organelles in the cells that turn fat into energy to fuel the body.

進一步的研究發現，DNA依賴蛋白激酶會促進營養物質轉化為脂肪，並且減少線粒體的數量——而線粒體是將脂肪轉化為能量以供應人體的細胞器。

Mitochondria can be found in abundance among young people, but the numbers drop considerably in older people.

年輕人體內存在著大量線粒體，但是老年人體內線粒體的數量卻大幅下降。

Researchers know that decreased mitochondria can promote obesity as well as loss of exercise capacity.

研究人員發現，線粒體數量的減少會促進肥胖、並且導致運動能力喪失。