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冲绳人长寿秘诀:与高碳水化合物饮食有关?

更新时间:2019/1/28 19:29:56 来源:纽约时报中文网 作者:佚名

A high-carb diet may explain why Okinawans live so long
冲绳人长寿秘诀:与高碳水化合物饮食有关?

The search for the “elixir of youth” has spanned centuries and continents – but recently, the hunt has centred on the Okinawa Islands, which stretch across the East China Sea. Not only do the older inhabitants enjoy the longest life expectancy of anyone on Earth, but the vast majority of those years are lived in remarkably good health too.

千百年以来,全球各地都在寻找“长生不老药”,最近对长生秘诀探索之旅来到了东中国海的冲绳群岛。当地老年居民不仅寿命在全球范围内是最长的,而且他们当中绝大多数人都活得非常健康。

Of particular note is the number of people who reach 100 years of life. For every 100,000 inhabitants, Okinawa has 68 centenarians – more than three times the numbers found in US populations of the same size. Even by the standards of Japan, Okinawans are remarkable, with a 40% greater chance of living to 100 than other Japanese people.

特别值得一提的是冲绳超过100岁的寿星人数。冲绳每10万居民中就有68位百岁老人,是美国同等规模人口的三倍多。即使按照日本的标准(日本为全球平均寿命最高的国家),冲绳人的寿命也是很突出的,与日本其他地区的人相比,冲绳人活过100岁可能性要高出40%。

Little wonder scientists have spent decades trying to uncover the secrets of the Okinawans’ longevity – in both their genes and their lifestyle. And one of the most exciting factors to have recently caught the scientists’ attention is the peculiarly high ratio of carbohydrates to protein in the Okinawan diet – with a particular abundance of sweet potato as the source of most of their calories.

难怪科学家们花费了数十年的时间试图揭示冲绳人长寿的秘密,包括他们的基因和生活方式。最令人激动的因素之一近期引起了科学家们的关注,即冲绳人饮食中碳水化合物与蛋白质的比例特别高,尤其是饮食中大量卡路里的主要来源­­——红薯。

“It is quite the opposite of current popular diets that advocate a high protein, low carb diet,” says Samantha Solon-Biet, who researches nutrition and ageing at the University of Sydney. Despite the popularity of the Atkins and Paleo diets, however, there is minimal evidence that high-protein diets really do bring about long-term benefits.

悉尼大学研究营养与衰老课题的梭伦-比尔特(Samantha Solon-Biet)说:“这与目前推崇的高蛋白质低碳水化合物的饮食模式正相反”。虽然阿特金斯健康饮食法(Atkins)和原始饮食法(Paleo)很受欢迎,但也没有什么证据表明高蛋白质饮食对身体有长期益处。

So could the “Okinawan Ratio” – 10:1 carbohydrate to protein – instead be the secret to a long and healthy life? Although it would still be far too early to suggest any lifestyle changes based on these observations, the very latest evidence – from human longitudinal studies and animal trials – suggest the hypothesis is worth serious attention. According to these findings, a low protein, high carbohydrate diet sets off various physiological responses that protect us from various age-related illnesses – including cancer, cardiovascular disease and Alzheimer’s disease. And the Okinawan Ratio may achieve the optimal dietary balance to achieve those effects.

那么“冲绳比例”,碳水化合物与蛋白质比例10:1才是健康长寿的秘诀吗?虽然光凭这些观察结果就倡导生活方式的改变还为时尚早,但对人类饮食长时间研究和动物试验获得的最新研究证据表明,冲绳比例假设值得密切关注。这些研究结果表明,低蛋白质、高碳水化合物饮食会引发各种生理反应,保护我们免受癌症、心血管疾病和阿尔茨海默病等各种老年疾病的折磨。冲绳的高碳水化合物低蛋白质比例或许达到了最佳的膳食平衡,从而获得了这些效果。

Much of this research comes from the Okinawa Centenarian Study (OCS), which has been investigating the health of the ageing population since 1975. The OCS examines inhabitants from across the Okinawa prefecture, which includes more than 150 islands. By 2016, the OCS had examined 1,000 centenarians from the region.

大部分研究来自“冲绳百岁老人研究”项目(OCS),这项研究自1975年以来一直在调查冲绳老年人口的健康状况。OCS调查范围覆盖了冲绳县内150多个岛屿的居民。到2016年,OCS已经调查了当地1000位百岁老人。

Rather than suffering a prolonged demise, the Okinawan centenarians appeared to have delayed many of the usual effects of ageing, with almost two thirds living independently until the age of 97. This remarkable “healthspan” was evident across many age-related diseases. The typical Okinawan centenarian appeared to be free of the typical signs of cardiovascular disease, without the build-up of the hard “calcified” plaques around the arteries that can lead to heart failure. Okinawa’s oldest residents also have far lower rates of cancer, diabetes and dementia than other ageing populations.

冲绳百岁老人似乎已经延迟了许多常见的衰老影响,他们不会在人生最后时段受到久病折磨,几乎三分之二的冲绳老人直到97岁都能独立生活。这种显著的“老年健康状况”在许多与年龄有关的疾病中也很明显。典型的冲绳百岁老人不会患上典型的老人心血管疾病,其动脉周边不会积累“钙化”的硬块而导致心力衰竭。与其他地区的老年人相比,冲绳最年长的居民患癌症、糖尿病和痴呆症概率也要低得多。

Genetic jackpot

遗传中头奖

Given these results, there is little doubt that Okinawa has an exceptional population. But what can explain that extraordinary longevity?

鉴于以上结果,冲绳人与众不同是毫无疑问的。但又如何解释这种不同寻常的长寿呢?

Genetic good fortune could be one important factor. Thanks to the geography of the islands, Okinawa’s populations have spent large chunks of their history in relative isolation, which may has given them a unique genetic profile. Preliminary studies suggest this may include a reduced prevalence of a gene variant – APOE4 – that appears to increase the risk of heart disease and Alzheimer’s. They may also be more likely to carry a protective variant of the FOXO3 gene involved in regulating metabolism and cell growth. This results in a shorter stature but also appears to reduce the risk of various age-related diseases, including cancer.

遗传运气好可能是一个重要因素。由于岛屿的地理位置特殊,冲绳群岛的居民自古以来处于较为孤立的状态,与外界交流较少,也因此可能拥有一些独特的遗传特征。初步研究表明,这些特征可能包括APOE4基因变异的患病率降低,APOE4基因会增加患心脏病和阿尔茨海默氏症的风险。冲绳人也更有可能携带能够调节代谢和细胞生长的FOXO3基因的保护性变体。这种基因保护性变体会导致身材矮小,但似乎也降低了癌症等与年龄有关的各种疾病的患病风险。

Even so, it seems unlikely that good genes would fully explain the Okinawans’ longevity, and lifestyle factors will also be important. The OCS has found that Okinawans are less likely to smoke than most populations, and since they worked predominantly in agriculture and fishing, they were also physically active. Their tight-knit communities also help the residents to maintain an active social life into old age. Social connection has also been shown to improve health and longevity by reducing the body’s stress responses to challenging events. (Loneliness, in contrast, has been shown to be as harmful as smoking 15 cigarettes a day.)

即便如此,遗传运气好似乎也不能完全决定冲绳人的长寿,生活方式也很重要。“冲绳百岁老人研究”(OCS)发现,与其他地区人口相比,冲绳人吸烟的概率很低,而且由于他们主要从事农业和渔业,身体也经常得到锻炼。他们紧密的社区氛围也让居民在老年阶段还能拥有丰富的社交生活。社交生活减轻了人们在面对挑战时的身体压力,有益于增强体质、延年益寿。(相比之下,孤独的感觉与每天吸15支香烟的危害是相等的。)

It is the Okinawans’ diet, however, that may have the most potential to change our views on healthy ageing. Unlike the rest of Asia, the Okinawan staple is not rice, but the sweet potato, first introduced in the early 17th Century through trade with the Netherlands. Okinawans also eat an abundance of green and yellow vegetables – such as the bitter melon – and various soy products. Although they do eat pork, fish and other meats, these are typically a small component of their overall consumption, which is mostly plant-based foods.

然而,冲绳人的饮食可能才是最能让我们对老年人健康改观的原因。与亚洲其他地区不同,冲绳人的主食不是大米,而是红薯。红薯最初是在17世纪初与荷兰人的对外贸易中引进的。冲绳人还吃大量的绿色和黄色蔬菜,例如苦瓜,以及各种豆制品。虽然他们也吃猪肉、鱼类和其他肉类,但只占日常饮食总体的一小部分,冲绳人平时吃得最多的还是植物性食物。

The traditional Okinawan diet is therefore dense in the essential vitamins and minerals - including anti-oxidants - but also low in calories. Particularly in the past, before fast food entered the islands, the average Okinawan ate around 11% fewer calories than the normal recommended consumption for a healthy adult.

所以,传统的冲绳饮食中含有大量人体必需的维生素和矿物质,包括抗氧化剂,但热量也很低。尤其是在冲绳岛还没有快餐行业的过去那些年,冲绳人平均摄入的热量比健康成人的正常推荐摄入量要少11%。

For this reason, some scientists believe that Okinawans offer more evidence for the life-enhancing virtues of a “calorie restricted” diet. Since the 1930s, some doctors and scientists have argued that continuously limiting the amount of energy you consume could have many benefits above and beyond weight loss – including a deceleration of the ageing process.

因此,一些科学家认为,冲绳人进一步证明“限制卡路里”饮食法有助于增强体质、改善生活。自20世纪30年代以来,一些医生和科学家认为,不断限制人体摄入的热量不仅有利于减重,还会带来许多其他益处,其中包括减缓衰老速度。

In one of the most compelling experiments, a group of resus macaques eating 30% fewer calories than the average monkey showed a remarkable 63% reduction in deaths from age-related diseases over a 20-year period. They also looked younger – they had fewer wrinkles and their fur retained its youthful lustre rather than turning grey. Due to practical difficulties, long-term clinical trials in humans have yet to be completed to test the effects on longevity, but a recent two-year experiment, funded by the US National Institute on Aging, was highly suggestive: participants on a calorie restricted diet showed better cardiovascular health – including lower blood pressure and cholesterol.

在一项最引人注目的实验中,一群普通猕猴 的卡路里摄入量比正常猴子的平均卡路里摄入量低30%,实验表明,在20年内,普通猕猴因患老年疾病的死亡率显着降低了63%。这些普通猕猴看起来也更年轻,皱纹很少,皮毛没有变灰,反而尽显年轻的光泽。由于实践难度大,类似的验证人类长寿的长期临床试验尚未完成,但最近由美国国家老龄化研究所资助的为期两年的实验高度表明:参与实验的人执行限制卡路里饮食后心血管更健康,血压和胆固醇都比较低。

It’s still not clear why a calorie restricted diet would be so beneficial, but there are many potential mechanisms. One possibility is that calorie restriction alters the cell’s energy signalling, so that the body devotes more resources to preservation and maintenance – such as DNA repair – rather than growth and reproduction, while limiting ‘oxidative stress’ caused by the toxic by-products of metabolism that can cause cellular damage.

目前还不清楚为什么限制卡路里饮食对人体许多潜在机制如此有益。其中一种可能性是限制卡路里改变了细胞的能量信号,所以身体不是停留在生长和繁殖层面,而是投入更多资源用于保存和维护自身,例如DNA修复,同时也减少了新陈代谢的有毒副产物引起的“氧化应激”对细胞的损伤。

The benefits of the Okinawan Diet may not end with its calorie restriction.

冲绳饮食模式的益处或许不止限制卡路里一方面。

Solon-Biet has conducted a series of studies examining the influence of dietary composition (rather than sheer quantity) on ageing in animals, and her team has consistently found that a high-carb, low-protein diet extends the lifespan of various species, with her most recent study showing that it reduces some of the signs of ageing in the brain. Amazingly, they have found that the optimum ratio is 10 parts carb to one part protein – the same as the so-called Okinawan Ratio.

梭伦-比尔特进行了一系列研究,包括膳食成分(而不是纯粹的数量)对动物衰老的影响。她的团队持续发现,高碳水化合物、低蛋白质饮食延长了各种物种的寿命。她最近的一项研究表明,高碳水化合物、低蛋白质饮食甚至有减少大脑衰老的一些迹象。令人惊讶的是,他们发现最佳比例是10份碳水化合物与1份蛋白质,与所谓的“冲绳比例”一致。

Although there aren’t yet any controlled clinical trials in humans, Solon-Biet cites epidemiological work across the world that all point to similar conclusions. “Other long-lived populations have also been shown to have dietary patterns that include relatively low amounts of protein,” she says. “These include the Kitavans, [who live on] a small island in Papua New Guinea, the South American Tsimane people and populations that consume the Mediterranean diet.”

尽管尚未对人类进行任何对照临床试验,但梭伦-比尔特指出全世界的流行病学工作都指出了类似的结论。她说:“其他长寿人群也表现出类似的饮食模式,其中包括相对少量的蛋白质。这些人群包括巴布亚新几内亚的一个小岛上的基塔瓦人、南美洲的齐曼内人以及保持地中海饮食模式的人。”

Once again, the exact mechanisms are murky. Like calorie restriction, the low protein diets seem to promote the cell repair and maintenance. Karen Ryan, a nutritional biologist at the University of California, Davis, points out that the scarcity of amino acids can encourage cells to recycle old material (rather than synthesising new proteins).

再次说明,这种饮食比例到底引起什么确切的机制反应,尚不清楚。看来如限制卡路里一样,低蛋白质饮食似乎能够促进细胞的修复和维护。加州大学戴维斯分校的营养生物学家瑞恩(Karen Ryan)指出,氨基酸的稀缺会促使细胞重复利用旧的成分(而不是合成新的蛋白质)。

“Together, these changes may prevent the ageing-associated accumulation of damaged proteins within cells,” she says. This build-up of damaged proteins may usually be responsible for many diseases, she says – but the regular clean up when we eat a low-protein diet could prevent it.

她说:“总之,这些变化可能会阻止与衰老有关的细胞内受损蛋白质的堆积。”她还说,这种受损蛋白质的堆积通常可能导致各种疾病,但如果我们选择低蛋白质饮食就能达到定期清理以预防各种疾病的效果。

So should we all start adopting the Okinawan Diet? Not quite. Ryan points to some evidence that low protein intake may limit bodily damage up to the age of 65, but you may then benefit from increasing your protein intake after that point. “Optimal nutrition is expected to vary across the life history,” she says. And it’s also worth noting one study, which found that the relative merits of protein and carbohydrates may depend on the protein's source: a diet higher in plant-based protein appears to be better than a diet rich in meat or dairy, for instance. So the Okinawans may be living longer due to the fact that they are eating (mostly) fruit and vegetables, rather than its high carb, low protein content.

那么我们是否都应该开始选择冲绳饮食模式吗?并非如此。瑞恩指出,有证据表明降低蛋白质摄入量可能对65岁以下的人有减轻身体伤害的作用,但65岁之后你又可能会因增加蛋白质摄入量而受益。她说:“对人体的最佳营养会在一生中有变化。”同样值得关注的是,一项研究发现,蛋白质和碳水化合物的相对优势可能取决于蛋白质的来源。例如,植物性蛋白质比重高的饮食模式可能要比肉类或乳制品比重高的饮食模式好。因此,冲绳人之所以长寿可能与他们(主要)吃水果和蔬菜有关,而不是因为高碳水化合物、低蛋白质的饮食模式。

Ultimately, the Okinawans’ health is probably due to a lucky confluence of many factors, Ryan says. “And specific interactions among these factors will also be important.” And we may need many more years of research to understand the importance of each of those ingredients before we finally come up with a true recipe for the “elixir of youth”.

归根结底,冲绳人的健康长寿可能是多种因素的幸运组合。 瑞恩说:“这些因素之间具体的相互作用也很重要。”在最终找到“青春灵药”真正的配方之前,我们可能还需要更多年的研究来了解每种因素的重要性。

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