Sharply cutting calories in the diets of rhesus monkeys was found to reduce aging-related deaths, according to a study that followed 76 monkeys for two decades.

    The findings, published Thursday in Science magazine by researchers at the University of Wisconsin, give new impetus to researchers and companies, including GlaxoSmithKline PLC （GSK）, that are searching for a drug to mimic the beneficial effects of a meager diet in humans without the feeling of near-starvation.

    For thousands of people who already attempt to sharply restrict their food intake - by as much as 30% below a normal diet of roughly 2,200 calories a day - in an effort to live longer, the findings appear to validate a technique called calorie restriction as a way to live longer.

    Scientists have known since the 1930s that the technique lengthens the lives of mice. But until now, no study had shown the technique worked in monkeys, which are more genetically similar to humans. One difficulty: Monkeys live almost 30 years on average, meaning any study to measure a difference in death rates would need to wait a long time.

    The Wisconsin study, which began in 1989 with 30 rhesus monkeys and added 46 more in 1994, is the first to yield a definitive finding. Researchers beg an restricting half the monkeys' diets, reducing their calories by 30%, when the monkeys were fully grown, or about 10 years old.

    Thursday's findings are 'all consistent with what human practitioners of calorie restriction have always believed,' said Brian Delaney, president of the Calorie Restriction Society, which claims about 3,000 members. 'Any degree of restriction beyond what you're currently eating will confer health benefits and will slow the aging process,' he said.

    After almost 20 years, 14 of 38 monkeys in the control group had died of what were considered age-related causes, such as heart disease and cancer. That compares with only five of 38 monkeys in the restricted-diet group, a significant decrease. However, the difference wasn't statistically significant when considering all causes of death, including monkeys who died from injuries and complications from anesthesia.

    Calorie restriction also appeared to slow the loss of gray matter in the brain.

    'It's a pretty simply story, really,' said Richard Weindruch, a Wisconsin professor who led the study. 'We've been waiting all these years for the monkeys to become old enough to get meaningful data on lifespan and brain aging and diseases.'

    He is the co-founder of a Wisconsin company, LifeGen Technologies LLC, that works with drug makers to quantify the effect of possible life-extending drugs.

    根據(jù)一項(xiàng)為期20年對(duì)76只獼猴進(jìn)行的研究，大幅降低猴子飲食的熱量能降低它們死于與衰老相關(guān)疾病的幾率。

    這份威斯康星大學(xué)（University of Wisconsin）研究人員的研究報(bào)告刊登在周四的《科學(xué)》（Science）雜志上。這些研究發(fā)現(xiàn)給諸多研究人員和葛蘭素史克（GlaxoSmithKline）等公司帶來(lái)了新的動(dòng)力。這些人員和公司一直在尋找一種藥物能夠模擬節(jié)食給人帶來(lái)的好處，又不用感受到饑餓的痛苦。

    目前已經(jīng)有數(shù)以千計(jì)的人嘗試嚴(yán)格限制他們的食物攝取量──較之每天約2,200卡的正常攝入量低至多30%──以試圖延長(zhǎng)壽命。對(duì)他們來(lái)說(shuō)，這項(xiàng)研究結(jié)果似乎證明了熱量限制是一種延長(zhǎng)壽命的手段。

    自上世紀(jì)三十年代以來(lái)，科學(xué)家就已經(jīng)知道這種方法能夠延長(zhǎng)老鼠的壽命。但到目前為止，還沒(méi)有研究顯示這種方法在猴子身上的效果，猴子和人類的基因有更多相似之處。但此類研究面臨著一個(gè)困難：猴子平均可以活將近30年，這意味著任何衡量壽命差別的研究都需要等待很長(zhǎng)時(shí)間。

    威斯康辛大學(xué)的這項(xiàng)研究是首個(gè)得出明確結(jié)果的。研究開始于1989年，當(dāng)時(shí)有30只獼猴，1994年又加入了46只猴子。當(dāng)猴子長(zhǎng)到10歲左右、發(fā)育完全成熟時(shí)，研究人員對(duì)半數(shù)猴子的飲食進(jìn)行了限制，將熱量攝入削減30%.

    美國(guó)熱量限制學(xué)會(huì)（Calorie Restriction Society）會(huì)長(zhǎng)德拉尼（Brian Delaney）表示，周四公布的研究結(jié)果和那些身體力行熱量限制的人一直堅(jiān)信的信念完全一致。該學(xué)會(huì)有大約3,000名會(huì)員。他說(shuō)，限制你當(dāng)前的進(jìn)食量，不管程度如何，都能帶來(lái)健康方面的好處，能夠延緩老化過(guò)程。

    在大約20年后，在38只飲食不受限制的猴子中，有14只猴子死于與老化有關(guān)的疾病，例如心臟病和癌癥。相比之下，另外38只飲食受到限制的猴子中，只有5只猴子死于同樣的原因，差距明顯。不過(guò)，在考慮所有死因之后，這種差距在統(tǒng)計(jì)上還不夠大，因?yàn)檫�有猴子死于外傷以及麻醉并發(fā)癥。

    限制熱量攝入似乎還可以延緩大腦灰質(zhì)的損失。

    負(fù)責(zé)這項(xiàng)研究的威斯康辛大學(xué)教授溫德魯奇（Richard Weindruch）說(shuō)，這真的是個(gè)非常簡(jiǎn)單的結(jié)論。這些年來(lái)，我們一直在等待猴子們變得足夠衰老，以獲得有關(guān)壽命、大腦老化以及疾病的有價(jià)值數(shù)據(jù)。

    溫德魯奇是當(dāng)?shù)匾患夜�司LifeGen Technologies LLC的共同創(chuàng)始人。該公司與制藥商合作，對(duì)可能延長(zhǎng)壽命的藥物成效進(jìn)行量化衡量。