每天八杯水 真的有必要吗？
2010-08-11 01:44:48   来源：看英语   评论：0 点击：

　　最近，摒弃每天八杯水的所谓“医学神话”已成为一种时尚。
　　Lately it has been in vogue to dismiss the advice to drink eight glasses of water a day as a 'medical myth'.

　　有关书籍和医学期刊文章已经宣称，“8 x 8”饮水原则──即每天八杯水，每次八盎司（237毫升）──能够为人体健康带来诸多益处，从加速减肥，排除体内毒素，对抗便秘、疲劳和皮肤干燥，到加快感冒和流感的康复等等，此类说法缺乏科学根据。媒体更戏称“8 x 8”饮水原则“并非滴水不漏”，而且也“无法除污”。
　　Books and medical-journal articles have declared there's no scientific evidence for claims that '8 x 8' -- eight ounces, or 237 milliliters, of water eight times a day -- can bring a wide range of benefits, from speeding weight loss to ridding the body of toxins, fighting constipation, fatigue and dry skin and hastening recovery from colds and the flu. Headlines have jeered that 8 by 8 'doesn't hold water' and 'water advice doesn't wash.'

　　其实，这种争论更多的是有关看问题的角度。
　　It's really more a dispute over whether the glass is half-empty or half-full.

　　许多研究将多饮水与有益健康联系在一起，但是批评人士通常认为此类研究数据不充分，结论不确定，或者并非广泛适用。
　　Many studies have linked drinking extra water with health benefits, but critics generally dismiss them as statistically insignificant, inconclusive or not widely applicable.

　　比如说，1999年发表在《新英格兰医学期刊》(New England Journal of Medicine)上的一项针对近4.8万名男性的10年期研究显示，人们每天每饮一杯水，罹患膀胱癌的风险就会下降7%。其它研究则发现，饮水越多，出现具有癌症前期特征的结肠息肉的机率就越小。发表在《美国流行病学期刊》(American Journal of Epidemiology) 上的一项针对加利福尼亚州两万名耶稣复临论者的研究发现，与每天只饮两杯水的人相比，每天至少饮用五杯水的女性患致命性心脏病的机率要低41%，男性要低 54%。
　　For instance, a 10-year study of nearly 48,000 men published in the New England Journal of Medicine in 1999 found that the risk of bladder cancer fell 7% for every cup subjects drank per day. Other studies have found that the more water subjects drank, the fewer precancerous colon polyps they had. And a study of 20,000 Seventh-day Adventists in California in the American Journal of Epidemiology found that women who drank at least five glasses of water a day had a 41% lower risk of fatal heart disease, and men had a 54% lower risk, compared with those who drank just two glasses a day.

　　广告达特茅斯医学院(Dartmouth Medical School)的生理学家亨氏·瓦尔丁(Heniz Valtin)在2002年发表于《美国生理学期刊》(American Journal of Physiology)上的一篇开创性文章里就上述研究进行了探讨，并且得出结论称，这些研究并不能支持每人每天饮用八杯水的普遍性建议，只是适用于那些已知有可能患有某些疾病的人。六年后，瓦尔丁博士称，我尚未见到任何科学报告与我得出的结论有悖。
　　Physiologist Heniz Valtin of Dartmouth Medical School discussed these studies and more in a seminal 2002 article in the American Journal of Physiology -- and still concluded that they didn't support a universal recommendation that everyone drink 8 by 8, just people 'known to have a propensity for the disease(s) in question.' Six years later, Dr. Valtin says, 'I haven't seen a single scientific report that disagrees with my conclusion.'