After a series of conflicting reports about whether vitamin pills can stave off chronic disease, researchers announced on Wednesday that a large clinical trial of nearly 15,000 older male doctors followed for more than a decade found that those taking a daily multivitamin experienced 8 percent fewer cancers than the subjects taking dummy pills.
While many studies have focused on the effects of high doses of particular vitamins or minerals, like calcium and vitamin D, this clinical trial examined whether a common daily multivitamin had an effect on overall cancer risk. A randomized, double-blinded clinical trial, the kind considered the most rigorous type of study, it was one of the largest and longest efforts to address questions about vitamin use.
The findings were to be presented Wednesday at an American Association for Cancer Research conference on cancer prevention in Anaheim, Calif., and the paper was published online in The Journal of the American Medical Association.
這項研究結果已于上周四在加州阿納海姆市舉行的美國癌癥研究協會(American Association for Cancer Research conference)癌癥預防會議上宣讀，并在《美國醫學會期刊》(The Journal of the American Medical Association)的在線版發表。
The reduction in total cancers was small but statistically significant, said the study’s lead author, Dr. J. Michael Gaziano, a cardiologist at Brigham and Women’s Hospital and the VA Boston Healthcare System. While the main reason to take a multivitamin is to prevent nutritional deficiencies, Dr. Gaziano said, “it certainly appears there is a modest reduction in the risk of cancer from a typical multivitamin.”
這項研究的主要作者J·邁克爾·加茲亞諾(Dr. J. Michael Gaziano)目前在布萊根婦女醫院(Brigham and Women’s Hospital)和波士頓醫療保健系統 (VA Boston Healthcare System)擔任心臟病?？漆t生，他說，研究發現，癌癥發病數降低的總體數字并不大，但具有顯著的統計學意義。他還介紹說，雖然服用復合維生素的主要原因在于預防營養缺乏，但是，“研究結果顯然可以說明，服用常用的復合維生素，就可以適度降低癌癥的發病危險。”
He noted that other measures are likely to protect against cancer more effectively than the daily use of multivitamins.
“It would be a big mistake for people to go out and take a multivitamin instead of quitting smoking or doing other things that we have a higher suspicion play a bigger role, like eating a good diet and getting exercise,” Dr. Gaziano said. “You’ve got to keep wearing your sunscreen.”
The study was supported by the National Institutes of Health and a grant, initiated by the investigators, from the chemical company BASF. Pfizer provided the multivitamins. The sponsors did not influence the study design, data analysis or manuscript preparation, the authors said.
這項研究得到了美國國家衛生研究所(National Institutes of Health)的支持，研究資金由化學公司巴斯夫(BASF)提供。輝瑞制藥(Pfizer)提供了復合維生素。研究者說，贊助公司并未對研究設計、數據分析或文稿準備施加影響。
About half of all Americans take some form of a vitamin supplement, and at least one-third take a multivitamin. But many recent vitamin studies have been disappointing, finding not only a lack of benefit but even some harm associated with large doses of certain supplements. The 2010 dietary guidelines for Americans state that there is no evidence to support taking a multivitamin or mineral supplement to prevent chronic disease.
大約半數美國人會服用某種維生素補劑，至少三分之一服用復合維生素。但不少近期關于維生素的研究其結果令人失望，這些研究發現服用維生素不僅無法對健康產生益處，如果大劑量服用某些補劑，甚至還可能傷害身體?！?010年美國居民膳食指南》(2010 dietary guidelines for Americans)中表明，沒有證據支持服用復合維生素或礦物質補劑能有效預防慢性病。
The American Cancer Society recommends that people eat a balanced diet, but that those who take supplements choose a balanced multivitamin that contains no more than 100 percent of the daily value of most nutrients.
美國癌癥協會(American Cancer Society)推薦人們均衡飲食，如果需要服用補劑，則應選擇一種配比均衡的復合維生素，大部分營養素的劑量都不要超過每日推薦量的100%。
Though several researchers said they were somewhat surprised by the findings, others called the results encouraging.
“It is a small overall effect, but from a public health standpoint, it could be of great importance,” said Dr. E. Robert Greenberg, an affiliate at Fred Hutchinson Cancer Research Center in Seattle. “Other than quitting smoking, there’s not much else out there that has shown it will reduce your cancer risk by nearly 10 percent.”
“它產生的總體影響并不大，但從公共衛生的角度來說具有重要意義，”西雅圖弗雷德·哈欽森癌癥研究中心(Fred Hutchinson Cancer Research Center)成員E·羅伯特·格林伯格醫生(Dr. E. Robert Greenberg)說：“除了戒煙，還沒有多少因素能將人們患癌的風險降低近10%。”
Multivitamin use had no effect on the incidence of prostate cancer, which was the most common cancer diagnosed in the study participants. When researchers looked at the effect of vitamin use on all other cancers, they found a 12 percent reduction in occurrence. Overall cancer deaths were reduced among vitamin users, but the difference was not statistically significant.
A major limitation of the study is that it included only male doctors, who were particularly healthy, with extremely low smoking rates, said Marji McCullough, a nutritional epidemiologist with the American Cancer Society. “We still need to find out whether these findings can be applied to others in the population,” she said.
The research effort might have benefited from the fact that the doctors who participated were diligent about taking their pills, and the researchers suggested that the effect of multivitamin use might have been muted because the participants were health-conscious to begin with.
Dr. David Chapin, 73, a gynecologist at Beth Israel Deaconess Medical Center in Boston who participated in the trial, said that although he had “never believed” in vitamins, he might start taking a daily multivitamin now, despite the modest benefit.
73歲的大衛·查賓(Dr. David Chapin)醫生是波士頓伯斯·以色列·狄肯尼斯醫學中心(Beth Israel Deaconess Medical Center)的婦科大夫，他說盡管他“從來都不信”維生素，而且這項研究中維生素帶來的益處非常輕微，但他可能會打現在起，每天堅持服用復合維生素。
“A lot of studies make big news, but when you look at the nitty-gritty, they don’t show all that much,” Dr. Chapin said, adding that he recently discovered he had been taking a placebo pill. “This was a very reliable study, it was very well designed and administered, and it went on and on and on.”