This Is Your Brain on Coffee
研究顯示咖啡對大腦有益
For thousands of years, coffee has been one of the two or three most popular beverages on earth. But it’s only recently that scientists are figuring out that the drink has notable health benefits. In one large-scale epidemiological study from last year, researchers primarily at the National Cancer Institute parsed health information from more than 400,000 volunteers, ages 50 to 71, who were free of major diseases at the study’s start in 1995. By 2008, more than 50,000 of the participants had died. But men who reported drinking two or three cups of coffee a day were 10 percent less likely to have died than those who didn’t drink coffee, while women drinking the same amount had 13 percent less risk of dying during the study. It’s not clear exactly what coffee had to do with their longevity, but the correlation is striking.
成百上千年來(lái)，咖啡一直是地球上最流行的兩三種飲料中的一種。但直至近期，科學(xué)家才漸漸發(fā)現這種飲料擁有引人注目的健康效益。在一項去年發(fā)表的大規模流行病學(xué)研究中，主要來(lái)自美國國家癌癥研究所(National Cancer Institute)的研究人員分析了40多萬(wàn)名年齡在50-71歲的志愿者的健康信息，在研究起始的1995年，這些志愿者都沒(méi)有患大病。到了2008年，其中有5萬(wàn)多人去世。但自稱(chēng)每天喝兩三杯咖啡的男性，相比完全不喝咖啡的男性，死亡風(fēng)險低了10%，而喝同樣份量咖啡的女性在研究期間死亡的風(fēng)險低了13%。研究者無(wú)法確切得知咖啡對被訪(fǎng)者的長(cháng)壽產(chǎn)生了何種作用，但這種關(guān)聯(lián)確實(shí)是驚人的。
Other recent studies have linked moderate coffee drinking — the equivalent of three or four 5-ounce cups of coffee a day or a single venti-size Starbucks — with more specific advantages: a reduction in the risk of developing Type 2 diabetes, basal cell carcinoma (the most common skin cancer), prostate cancer, oral cancer and breast cancer recurrence.
還有些近期的研究則發(fā)現，適量飲用咖啡——每天喝三四杯咖啡，每杯為5盎司（約140克），也即是一杯星巴克的特大杯(venti)咖啡——可帶來(lái)更加明確的益處：減少患II型糖尿病、基底細胞癌（最常見(jiàn)的皮膚癌）、前列腺癌、口腔癌和乳腺癌復發(fā)風(fēng)險。
Perhaps most consequential, animal experiments show that caffeine may reshape the biochemical environment inside our brains in ways that could stave off dementia. In a 2012 experiment at the University of Illinois at Urbana-Champaign, mice were briefly starved of oxygen, causing them to lose the ability to form memories. Half of the mice received a dose of caffeine that was the equivalent of several cups of coffee. After they were reoxygenated, the caffeinated mice regained their ability to form new memories 33 percent faster than the uncaffeinated. Close examination of the animals’ brain tissue showed that the caffeine disrupted the action of adenosine, a substance inside cells that usually provides energy, but can become destructive if it leaks out when the cells are injured or under stress. The escaped adenosine can jump-start a biochemical cascade leading to inflammation, which can disrupt the function of neurons, and potentially contribute to neurodegeneration or, in other words, dementia.
而最重要的發(fā)現是：動(dòng)物試驗顯示咖啡因或許可以改造我們大腦中的生化環(huán)境，防止癡呆癥的發(fā)生。2012年，伊利諾伊大學(xué)厄巴納-香檳分校(University of Illinois at Urbana-Champaign)進(jìn)行了一項試驗，試驗小鼠暫時(shí)處于缺氧環(huán)境中，因此喪失了形成記憶的能力。其中半數小鼠隨后服用了一劑相當于幾杯咖啡量的咖啡因。在重新吸到氧氣后，服用了咖啡因的小鼠恢復形成新記憶的速度比沒(méi)有服用的小鼠快了33%。檢查小鼠的腦組織可以發(fā)現，咖啡因破壞了腺苷的活動(dòng)，這種存在于細胞內的物質(zhì)通?？梢怨┙o能量，但細胞受損或應激時(shí)釋放出來(lái)時(shí)，則可帶來(lái)破壞性的后果。逃逸的腺苷能啟動(dòng)一組生化劇變，引發(fā)炎癥，而這會(huì )破壞神經(jīng)元功能，因此可能導致神經(jīng)退行性疾病，也即是癡呆癥。
In a 2012 study of humans, researchers from the University of South Florida and the University of Miami tested the blood levels of caffeine in older adults with mild cognitive impairment, or the first glimmer of serious forgetfulness, a common precursor of Alzheimer’s disease, and then re-evaluated them two to four years later. Participants with little or no caffeine circulating in their bloodstreams were far more likely to have progressed to full-blown Alzheimer’s than those whose blood indicated they’d had about three cups’ worth of caffeine.
在2012年的一項人體試驗中，來(lái)自南佛羅里達大學(xué)(University of South Florida)和邁阿密大學(xué)(University of Miami)的研究人員對長(cháng)者血液中的咖啡因濃度進(jìn)行檢測，這些老年人要么出現了輕度認知障礙，要么開(kāi)始初現嚴重健忘癥狀，而這通常是患阿爾茨海默癥的征兆。在2-4年后，研究者對他們再次進(jìn)行檢測。血液中含極少或完全不含咖啡因的人阿爾茨海默癥嚴重惡化的可能性，要遠甚于血檢結果顯示每天喝三杯咖啡的受試者。
There’s still much to be learned about the effects of coffee. “We don’t know whether blocking the action of adenosine is sufficient” to prevent or lessen the effects of dementia, says Dr. Gregory G. Freund, a professor of pathology at the University of Illinois who led the 2012 study of mice. It is also unclear whether caffeine by itself provides the benefits associated with coffee drinking or if coffee contains other valuable ingredients. In a 2011 study by the same researchers at the University of South Florida, for instance, mice genetically bred to develop Alzheimer’s and then given caffeine alone did not fare as well on memory tests as those provided with actual coffee. Nor is there any evidence that mixing caffeine with large amounts of sugar, as in energy drinks, is healthful. But a cup or three of coffee “has been popular for a long, long time,” Dr. Freund says, “and there’s probably good reasons for that.”
對于咖啡的效果，現在人們仍然知之甚少。格里高利·G·弗倫德(Gregory G. Freund)博士是伊利諾伊大學(xué)病理學(xué)教授，也是2012年那項小鼠試驗的組織者，他說(shuō)，“我們尚不明確，阻滯腺苷的活動(dòng)是否足以”防止或減弱其對癡呆癥的影響。目前也不能確切得知，喝咖啡帶來(lái)的益處主要在于它含有的咖啡因，還是其中的其他有益成份。比方說(shuō)，在2011年由南佛羅里達大學(xué)的同一組研究人員還做了一項試驗，經(jīng)過(guò)基因改造而易患上阿爾茨海默癥的小鼠要接受記憶力測試，結果服用咖啡因的小鼠表現不如喝真正的咖啡的小鼠好。此外，也沒(méi)有證據表明將咖啡因混合大量糖——這就是功能飲料——有健康益處。但是，弗倫德博士說(shuō)，每天喝三兩杯咖啡“已經(jīng)時(shí)興了很長(cháng)很長(cháng)時(shí)間，而且這么做也許是有很好的理由的?！?/p>
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