纽约（路透社健康专栏）－根据新的研究发现：服用抗氧化剂或其他维生素似乎不能延缓阻塞性动脉硬化斑块的聚集，后者可导致心脏病或中风。
这些发现来自于对16个临床试验的分析，这为补充维生素不能防止心脏病、中风以及心血管疾病引起的死亡增加了更多证据。
虽然研究者试图希望B族维生素和抗氧化剂如维生素C或E具有保护作用，但近年来的临床试验未能证实这种预期。一些研究甚至提示这些添加物可能对心脏有害。
位于巴尔迪莫的约翰霍普金斯公共卫生学院的流行病学副教授Eliseo Guallar博士说：“我认为这些临床试验的结果完全是阴性的。”
他还告诉路透社健康专栏：一些研究者曾辩论说维生素可能抑制动脉粥样硬化的进展――后者在动脉壁的积聚最终可引起心脏病发作和中风。对心脏病和中风没有表现有益效果的原因，可能是否在动脉粥样硬化进程中给予维生素太晚。
为证实这些添加物能否抑制动脉粥样硬化，Guallar及其同事综合分析了临床试验中的各种结果，包括叶酸和其他B族维生素、抗氧化作用的维生素如维生素C、E以及β-胡萝卜素。一些试验的参与者补充单种维生素，而另外一些试验中的参与者则补充多种维生素的复合制剂。研究者未发现某种维生素可以延缓动脉粥样硬化进程的证据。Guallar 说：“最后的结果是阴性的。”
Gualla指出：虽然添加制剂没有显示心脏保护作用，但这仍不能否定饮食的重要性。食物中的营养成分和制剂中的维生素是完全不同的。
他建议人们尽力保持健康的生活方式，包括戒烟、规律的运动以及吃包括水果、蔬菜和各种谷物的平衡饮食。
Guallar 说：“那些依靠维生素来预防心血管疾病的人轻则是在浪费金钱，重则或许是在损害健康。” 他提倡将钱花到其他地方如健身房。
来源：美国临床营养杂志，2006年10月
More evidence vitamins don't slow heart disease
Wed Oct 25, 2006 11:31 PM BST
By Amy Norton
NEW YORK (Reuters Health) - Taking antioxidants or other vitamins does not seem to slow the buildup of artery-clogging plaques that can lead to heart disease or stroke, according to a new study.
The findings, from an analysis of 16 clinical trials, add to evidence that vitamin supplements do not prevent heart attacks, strokes or deaths from cardiovascular disease.
Though researchers had hoped that B vitamins and antioxidants, such as vitamins C and E, would offer some protection, clinical trials in recent years have failed to confirm those expectations. Some studies have even suggested supplements might be harmful to heart health.
"I think (the results of) those trials have been overwhelmingly negative," said Dr. Eliseo Guallar, an associate professor of epidemiology at Johns Hopkins School of Public Health in Baltimore.
Still, he told Reuters Health, some researchers have argued that the vitamins may hinder the progression of atherosclerosis -- the accumulation of plaques on the artery walls that can eventually lead to heart attack or stroke.
The lack of benefit against heart attacks and strokes might, for instance, be the result of starting the vitamins too late in the course of atherosclerosis.
To see whether supplements might forestall atherosclerosis, Guallar and his colleagues pooled the results from clinical trials that tested folic acid and other B vitamins, or antioxidant vitamins, such as vitamins C, E and beta-carotene. In some studies, participants took a single vitamin supplement, while in others various supplement combinations were used.
The researchers found no evidence that any of the vitamins slowed the progression of atherosclerosis.
"The end result is, there is nothing," Guallar said.
The fact that pills do not seem to offer heart protection doesn't negate the importance of diet, however. The nutrients in foods and the large vitamin doses found in pills are fundamentally different, Guallar noted.
He advised that people strive to maintain a generally healthy lifestyle, which includes not smoking, getting regular exercise and eating a balanced diet rich in fruits, vegetables and whole grains.
People who rely on vitamins for preventing cardiovascular disease are "at least wasting their money," Guallar said, and at worst, possibly harming their health.
He recommends spending money on something else, like a gym membership.
SOURCE: American Journal of Clinical Nutrition, October 2006.
http://today.reuters.co.uk/news/articlenews.aspx?type=healthNews&storyID=2006-10-25T223105Z_01_KNE581017_RTRIDST_0_HEALTH-VITAMINS-HEARTDISEASE-DC.XML
编辑：蓝色幻想
