復(fù)合維生素可降低患癌風(fēng)險

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.

關(guān)于維生素是否可以減少慢性病的發(fā)作，此前已經(jīng)發(fā)表過一系列前后矛盾的研究報告，而在上周三，研究者宣布，他們對近1.5萬名年長男性醫(yī)生進行了為期超過10年的大型臨床試驗，結(jié)果發(fā)現(xiàn)每天服用一粒復(fù)合維生素的人，患癌癥的風(fēng)險較每天服用安慰劑的人少了近8%。

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.

此前很多研究專注于研究大劑量服用某種特定的維生素或者礦物質(zhì)——比如鈣和維生素D，會對健康帶來什么樣的影響，而該項臨床試驗研究的是每天服用普通的復(fù)合維生素，是否對患癌的風(fēng)險產(chǎn)生影響。這項研究采用的是隨機雙盲臨床測試，這被認為是最嚴格的測試方法，迄今為止，這也是對服用維生素對健康帶來的作用所進行的規(guī)模最大、時間跨度最長的研究之一。

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(jié)果已于上周四在加州阿納海姆市舉行的美國癌癥研究協(xié)會(American Association for Cancer Research conference)癌癥預(yù)防會議上宣讀，并在《美國醫(yī)學(xué)會期刊》(The Journal of the American Medical Association)的在線版發(fā)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(yī)院(Brigham and Women’s Hospital)和波士頓醫(yī)療保健系統(tǒng) (VA Boston Healthcare System)擔(dān)任心臟病專科醫(yī)生，他說，研究發(fā)現(xiàn)，癌癥發(fā)病數(shù)降低的總體數(shù)字并不大，但具有顯著的統(tǒng)計學(xué)意義。他還介紹說，雖然服用復(fù)合維生素的主要原因在于預(yù)防營養(yǎng)缺乏，但是，“研究結(jié)果顯然可以說明，服用常用的復(fù)合維生素，就可以適度降低癌癥的發(fā)病危險。”

He noted that other measures are likely to protect against cancer more effectively than the daily use of multivitamins.

不過他也指出，相比每天服復(fù)合維生素，還有些做法在減少罹患癌癥風(fēng)險方面可能更有用。

“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.”

“假如大家以為吃吃復(fù)合維生素就能安枕無憂，而沒有戒煙，或者做那些我們認為在抗癌方面可以發(fā)揮更大作用的事情，比如注意飲食，持續(xù)鍛煉，堅持涂防曬霜，那可就大錯特錯了，”加茲亞諾說。

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(wèi)生研究所(National Institutes of Health)的支持，研究資金由化學(xué)公司巴斯夫(BASF)提供。輝瑞制藥(Pfizer)提供了復(fù)合維生素。研究者說，贊助公司并未對研究設(shè)計、數(shù)據(jù)分析或文稿準(zhǔn)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(shù)美國人會服用某種維生素補劑，至少三分之一服用復(fù)合維生素。但不少近期關(guān)于維生素的研究其結(jié)果令人失望，這些研究發(fā)現(xiàn)服用維生素不僅無法對健康產(chǎn)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(jù)支持服用復(fù)合維生素或礦物質(zhì)補劑能有效預(yù)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(xié)會(American Cancer Society)推薦人們均衡飲食，如果需要服用補劑，則應(yīng)選擇一種配比均衡的復(fù)合維生素，大部分營養(yǎng)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.

一些研究者說，他們對本研究的結(jié)果感到有些意外，而另一些則認為這個結(jié)果鼓舞人心。

“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(chǎn)生的總體影響并不大，但從公共衛(wèi)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(yī)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(fēng)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.

復(fù)合維生素對前列腺癌的發(fā)病率未產(chǎn)生任何影響，而前列腺癌是參試人員中最常被確診出的癌癥。如果將前列腺癌剔除在外，對于其他所有癌癥，復(fù)合維生素可降低12%的發(fā)病率。同時，總體而言服用維生素者患癌后的死亡率也降低了，但這方面的區(qū)別沒有統(tǒng)計顯著性。

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.

美國癌癥協(xié)會的營養(yǎng)流行病學(xué)家馬吉·麥卡洛(Marji McCullough)說，這項研究存在一個重要的局限——它只調(diào)查了男性醫(yī)生，而這個群體吸煙率極低，總體來說非常健康。她說：“我們?nèi)孕枰私?，這個發(fā)現(xiàn)是否也能適用于其他人群。”

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.

由于參加測試的醫(yī)生會嚴謹?shù)貓猿址镁S生素，因此研究結(jié)果會更加可靠，此外研究者認為，這項研究中服用復(fù)合維生素的作用可能有所削弱，因為參加測試者本身就深具保健意識。