高蛋白飲食和壽命長短有關係嗎大綱

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Research shows that a diet high in protein and low in carbohydrates can help shed pounds and normalize blood-glucose levels, improvements that lower the risk of diabetes and cardiovascular disease.

研究表明，含有高蛋白、低碳水化合物的飲食有助於減肥並能使血糖水平恢復正常，而血糖水平得到改善能降低糖尿病和心血管疾病的患病風險。

But will you live longer on a high-protein, low-carb diet? Two studies in the current edition of the scientific journal Cell Metabolism suggest the opposite. One involved an experiment conducted on mice, the other an 18-year study of humans who had divulged their dietary habits. Both studies found a strong association between longevity and a low-protein, high-carbohydrate diet, although the human study bore a twist: Beyond age 65, higher protein levels appeared to promote longevity.

但你會因爲高蛋白、低碳飲食而活得更久嗎？科學期刊《細胞代謝》(Cell Metabolism)本期上的兩項研究認爲答案是否定的。其中一則研究涉及對老鼠進行的一項試驗，另一則項則對那些暴露自己飲食習慣的人進行了長達18年的研究。儘管針對人類進行的研究與最終的結論有些出入，即過了65歲以後，更高的蛋白水平似乎會延年益壽。但前述兩項研究均發現：在長壽與高蛋白、低碳水化合物的飲食習慣之間存在着一種強烈的關聯。

'Those high-protein diets were developed with a shortsighted vision,' said Valter D. Longo, a University of Southern California professor of gerontology and biological sciences and the lead author of the human study. 'On a high-protein, high-fat diet you can lose weight, but in the long run you may be hurting yourself.'

南加州大學(University of Southern California)老年醫學和生物科學教授、上述人類研究的首席作者瓦爾特・D・隆戈(Valter D. Longo)說：“那些高蛋白飲食的發展伴隨着一種短視現象。堅持高蛋白、健康高脂的飲食習慣，你是可以減肥，但長遠來看，你現在的所在所爲可能正在傷害你自己。”

These studies are anything but definitive, showing only associations derived from highly limited evidence. But in gerontology, the influence of protein consumption on longevity is a hot topic. Last year, the American Federation for Aging Research hosted a symposium on 'Optimal Protein Intake for Older Adults,' featuring a panel of scientists from academia and industry. No concrete answers emerged, except perhaps that protein consumption influences health in ways that are complex.

這些研究目前均無定論，僅僅顯示出了一些關聯性，這些關聯性還是從非常有限的證據中提煉出來的。但在老年醫學中，蛋白質攝取對壽命的影響是一個熱門話題。去年，美國聯邦老化研究所(American Federation for Aging Research)舉辦了一場有關“老年人最佳蛋白攝取量”的研討會，有一組來自學界和業界的科學家出席了會議。對於前述問題，大家尚未得出具體的答案，或許只有這樣一個結論：蛋白質攝取量會通過複雜的方式影響健康。

'High protein diets may be effective to lose weight rapidly,' said Elena Volpi, a professor of geriatrics at the University of Texas Medical Branch in Galveston. 'But very high protein diets may also be harmful.'

德克薩斯大學加爾維斯頓醫學分部(University of Texas Medical Branch in Galveston)老年病學教授埃琳娜・沃爾皮(Elena Volpi)說：“高蛋白飲食對快速減肥可能會有效，但特別高的蛋白飲食可能也會有害。”

In the human study, those consuming high levels of plant-based protein had a threefold increase in cancer mortality but no higher rate of overall mortality. That suggests, as other research has shown, that there may be benefits from minimizing consumption of animal-based protein. 'These results indicate that respondents ages 50 to 65 consuming moderate to high levels of animal protein display a major increase in the risks for overall and cancer mortality,' the researchers concluded.

在上述針對人類的研究中，那些攝取高植物蛋白的人羣癌症死亡率增加了三倍，但並未出現更高的總體死亡率。那表明──也正如其他研究所示──將動物蛋白攝入量最小化可能會有所裨益。研究人員得出結論稱：“這些結果表明，那些食用中到高水平動物蛋白、年齡在50到65歲的受訪者在總體死亡率和癌症死亡率方面的風險大幅增加。”

For subjects 66 and older, the opposite proved true: Higher protein consumption was associated with greater survival. Gerontologists say this makes sense, because the ability to absorb protein appears to diminish in the aging body, requiring perhaps greater consumption.

而在那些年齡爲66歲及以上的受訪者身上，事實證明情況正好相反：更高的蛋白質攝取量與更大的生存機會息息相關。老年病學者稱，這個完全說得通，因爲在衰老的身體內，吸收蛋白的能力似乎會減弱，這就可能需要更高的攝取量。

Even then, though, the takeaway is somewhat complicated. Americans tend to consume the bulk of their protein at dinner, and the body isn't always able to process an entire day's worth in one sitting, said Dr. Volpi, who wasn't involved in either study. 'It appears you can better use the protein you need if you distribute it across three meals, especially if you are a senior,' she said.

然而即便如此，有關蛋白質的攝取問題還是有些複雜。沃爾皮博士說，美國人傾向於在晚餐時進食他們一天中的大部分蛋白質，而人體並非總能一口氣消化掉一整天的營養。她還說：“如果你能將蛋白質的攝取任務分配到一日三餐中，你似乎就能更好地利用所需的蛋白質，尤其當你是位老年人時，情況更是如此。”沃爾皮並未參與到上述的任何研究中。

In one study, 858 mice were fed one of 25 diets with differing ratios of protein to carbohydrates. Those that ate higher ratios of protein were leaner. But they didn't live as long. 'Median life span increased (by about 30%) from about 95 weeks to 125 weeks as the protein-to-carbohydrate ratio decreased,' said the study, conducted by researchers in Australia. 'Our results show that healthy aging is not achieved in mice fed high protein diets.'

在其中一項研究中，有25種包含了不同蛋白質和碳水化合物比例的飲食，858只老鼠則會被餵食25種飲食當中的某一種。那些吃了更高比例蛋白質的老鼠更爲精瘦，但它們活得並不長。該研究稱：“隨着蛋白質比例相對碳水化合物比例的減少，老鼠的平均壽命長度也從大約95周增至125周（增幅約爲30%）。我們的結果顯示，健康老齡化並未體現在那些餵食了高蛋白飲食的老鼠身上。”這項研究是由澳大利亞的科研人員完成的。

Of course, mice aren't human. Indeed, the Australian researchers acknowledge that the same results may not be achieved in a different strain of mice.

當然，老鼠並非人類。的確，澳大利亞研究人員們承認，即便是不同品種的老鼠，實驗結果也會不一樣。

The second study followed 6,381 adult humans for 18 years after they completed a nationally administered survey on their food consumption over a 24-hour period. It divided the subjects into three groups: high-protein consumption (20% or more of calories from protein), moderate-protein consumption (10% to 19% from protein) and low-protein consumption (less than 10%).

第二項研究則在18年的時間裏對6,381位成年人進行了追蹤調查，在此之前所有受訪者都完成了一項有關他們在24小時時間段內食物攝取的全國性問卷調查。該研究將受訪者劃分爲三類：高蛋白攝取（有20%或以上的卡路里來自蛋白質）者，中等蛋白攝取（有10% 到 19%的卡路里來自蛋白質）者以及低蛋白攝取（不到10%的卡路里來自蛋白質）者。

In the 50-to-65 age range, 'subjects in the high protein group had a 74% increase in their relative risk of all-cause mortality, and were more than four times as likely to die of cancer when compared with those in the low-protein group,' the researchers reported.

在50歲到65歲的年齡段人羣中，研究人員報告稱：“高蛋白攝取組的受訪者全因死亡率的相對風險增加了74%。而當與低蛋白攝取組的同齡人相比時，高蛋白組死於癌症的可能性是前者的四倍多。”

One prominent diet expert and high-protein opponent, physician Ron Rosedale, saw the studies as vindicating his longtime warning about the risks of excessive protein. But Dr. Rosedale, who advocates a diet high in so-called healthy fats such as those found in avocados, argues that high levels of carbohydrate consumption are no less dangerous. 'If people take these studies as a thumbs up for high carbohydrates, that's missing the point,' he said.

著名飲食專家及高蛋白反對論者、醫師羅恩・羅斯代爾(Ron Rosedale)長期以來就對蛋白質攝取量過多發出了警告，他認爲上述研究正好證明了他的警告是對的。羅斯代爾博士提倡一種含有高健康脂肪的飲食，這種所謂的健康脂肪常見於諸如鱷梨這樣的食物中。羅斯代爾聲稱，高水平的碳水化合物攝取量所帶來的風險跟高蛋白飲食不相上下。他說：“如果人們將這些研究當成是對高碳水化合物飲食的讚許，那就是沒有抓住要旨。”