Cancer researchers urged people on Wednesday to take more vitamin D to lower their risk of colon, breast and ovarian cancer, saying studies showed a clear link. 

    "Our suggestion is for people to increase their intake," through diet or a vitamin supplement, Dr. Cedric Garland said in a telephone interview. 

    Garland's research team reviewed 63 studies, including several large long-term ones, on the relationship between vitamin D and certain types of cancer worldwide between 1966 and 2004. 

    He said the benefit of vitamin D was as clear as the harmful link between smoking and lung cancer. 

    "There's nothing that has this ability to prevent cancer," he said, urging governments and public health officials to do more to fortify foods with vitamin D. 

    Garland is part of a University of California at San Diego Moores Cancer Center team that published its findings this week online in the American Journal of Public Health. 

    The paper concluded that vitamin D deficiency may account for several thousand premature deaths from colon, breast, ovarian and other cancers annually. 

    Vitamin D is found in milk, as well as in some fortified orange juice, yogurt and cheeses, usually at around 100 international units (IU) a serving. 

    People might want to consider a vitamin supplement to raise their intake to 1000 IUs per day, Garland said, adding that it was well within the safety guidelines established by the National Academy of Sciences. 

    The authors said that taking more vitamin D could be especially important for people living in northern areas, which receive less vitamin D from sunshine. 

    African Americans, who don't produce as much of the vitamin because of their skin pigment, could also benefit significantly from a higher intake, the authors said. 

    美國研究人員12月28日表示，人們在日常飲食中應多攝入一些維生素D，以降低自身患結腸癌、乳腺癌和卵巢癌的危險。因為多項研究結果顯示，維生素D和人們患癌危險之間具有明確的關系。 

    據(jù)路透社12月28日報道，美國加利福尼亞大學的醫(yī)學教授塞德里克·加蘭德博士是該項目的研究人員之一。他的研究小組回顧了63項相關研究。這些都是1966年至2004年間，各國關于維生素D和某些癌癥間關系的研究，其中還不乏一些大型的、長期研究項目。 

    加蘭德說，維生素D能給人們帶來好處就像是吸煙能引發(fā)肺癌一樣，這兩者都是非常明確的。而維生素D攝入量不足則會導致全球每年有數(shù)千人因患結腸癌、乳腺癌、卵巢癌和其它一些癌癥過早地死亡。 

    因此，加蘭德號召人們補充每天的維生素D攝入量，他說：“我們建議人們增加維生素D的攝入量”，這可以通過日常飲食或者服用維生素補充劑來實現(xiàn)。 

    研究人員說，牛奶、一些加強了營養(yǎng)成分的果汁、酸奶和奶酪中的維生素D含量普遍約為100國際單位/每份。因此，人們可以考慮服用補充劑將自己的維生素D攝入量提升至每天1000國際單位（25微克）。而這一攝入量也符合美國國家科學院制定的相關安全指導方針。

    研究人員還表示，攝入更多的維生素D對于那些生活在美國北部地區(qū)的人們來說，顯得尤其重要，因為那里的人們因日曬少而獲取的維生素D量都比較少。