普通人服用维生素不能降低患病风险

美国预防医学工作组日前新发布的指南在回顾了84项研究后指出，普通人服用维生素既不能降低患心脏病和癌症的风险，也不能延长寿命，部分维生素在服用后甚至对身体有害。

Vitamin, mineral and multivitamin supplements aren't likely to protect you from cancer, heart disease or overall mortality, the US Preventive Services Task Force said in updated guidelines released Tuesday in the journal JAMA.

美国预防医学工作组在6月21日发表在《美国医学会杂志》上的新指南中写道，维生素、矿物质和复合维生素补充剂无法保护你不患癌症、心脏病，也不能帮你延长寿命。

Since its last recommendation in 2014, the task force reviewed 84 studies testing vitamins in almost 700,000 people, including 52 new studies on the topic.

继2014年发布上一则指南后，美国预防医学工作组回顾了84项测试维生素的研究，这些研究涵盖了近70万人，其中包括52项新研究。

Yet the conclusion remained the same as that of 2014: If you are a healthy, nonpregnant adult, there is "insufficient evidence" of any benefits to extending one's life in taking vitamin E, vitamin D, calcium, vitamin A, beta carotene, vitamin B3, vitamin B6, vitamin C and selenium.

然而，这一次的结论与2014年的结论一致：如果你是没有怀孕的健康成年人，没有足够的证据显示，服用维生素E、维生素D、钙片、维生素A、胡萝卜素、维生素B3、维生素B6、维生素C和硒补充剂对延长寿命有益。

However, there is enough evidence to recommend against the use of beta carotene supplements to prevent cardiovascular disease or cancer "because of a possible increased risk of mortality, cardiovascular mortality, and lung cancer," the task force said.

与此同时，美国预防医学工作组不建议人们服用胡萝卜素补充剂来预防心血管疾病或癌症，充分的证据显示，服用胡萝卜素“可能会增加死亡风险、心血管病病死率和肺癌风险”。

Nor should people take vitamin E "because it probably has no net benefit in reducing mortality, cardiovascular disease, or cancer," the task force said.

美国预防医学工作组称，人们也不应该服用维生素E，“因为维生素E很可能无益于降低死亡率、心血管病或癌症风险”。

"Lifestyle counseling to prevent chronic diseases in patients should continue to focus on evidence-based approaches, including balanced diets that are high in fruits and vegetables and physical activity," said Dr. Jeffrey Linder, chief of general internal medicine at Northwestern University's Feinberg School of Medicine in Chicago, in an accompanying editorial.

美国芝加哥西北大学范伯格医学院普通内科学主任杰弗里·林德博士在附加评论中写道：“预防慢性病的生活方式建议应继续关注有据可循的方法，包括富含水果、蔬菜等的平衡膳食。”

Take, for example, the Mediterranean diet. Eating the Mediterranean way, which focuses on a plant-based diet, physical activity and social engagement, can reduce the risk for high cholesterol, dementia, memory loss, depression and breast cancer, numerous studies found.

Meals from the sunny Mediterranean region have also been linked to weight loss, stronger bones, a healthier heart and longer life.

以地中海饮食为例。众多研究发现，地中海饮食以植物性膳食为主，注重身体活动和社交应酬，可降低患高胆固醇、痴呆、记忆力减退、抑郁和乳腺癌的风险。阳光充足的地中海地区饮食还与减肥、更强壮的骨骼、更健康的心脏和更长的寿命有关。

Another evidence-based intervention: the DASH diet, which stands for "dietary approaches to stop hypertension." The diet successfully reduces high blood pressure, studies have shown. Both the Mediterranean and DASH diets avoid processed foods and focus on fruits, vegetables, beans, whole grains, nuts and seeds.

另一个基于实证的介入方法是得舒饮食法，据称这是“防止高血压的饮食法”。多项研究表明，这种饮食法可成功降低高血压。地中海饮食和得舒饮食法都避免摄入加工食品，主要吃水果、蔬菜、豆类、全谷物、坚果和种子。

"Rather than focusing money, time, and attention on supplements, it would be better to emphasize lower-risk, higher-benefit activities ... following a healthful diet, getting exercise, maintaining a healthy weight, and avoiding smoking," Linder and his colleagues wrote.

林德和他的同事写道：“与其把金钱、时间和精力花在服用补充剂上，不如去从事风险低、获益高的活动……坚持健康饮食、定期锻炼身体、保持健康体重、尽量不吸烟。”

There are some populations who do need certain vitamins. Some seniors may need additional supplementation of vitamin B12 and B6 as absorption of those vitamins from food fades as we age. Because the elderly often get less sun than younger ages, they may need additional vitamin D, but levels should be checked by a doctor, as too much D can be harmful.

不过，某些人群确实需要服用特定维生素。有些老年人可能需要补充维生素B12和维生素B6，因为随着年龄增大，他们从食物中吸收的这些维生素会减少。由于老年人往往晒太阳比年轻人少，他们可能需要补充维生素D，但是用量必须遵医嘱，因为摄入过量维生素D可能对身体有害。