美国研究人员最新研究发现,大剂量摄入维生素D或可显著降低罹患乳腺癌等疾病的风险。
参与研究的加利福尼亚大学圣迭戈分校教授塞德里克·加兰在一份新闻公报中说,他们的研究发现,成人每日摄入2000至4000国际单位(维生素D的1国际单位相当于0.025微克)维生素D可使血液中维生素D的代谢产物维持在一定水平,从而显著降低罹患一些疾病的风险,包括乳腺癌、结肠癌、多发性硬化症和I型糖尿病等。
研究人员说,他们对数千名每日服用1000至10000国际单位维生素D的成人进行调查,得出上述结论。参与调查期间,被调查对象需要定期接受血液检测,以确定他们血液中维生素D代谢产物的水平。
根据美国国家卫生研究院上世纪推荐的维生素D摄入标准,50岁以下的人每日维生素D摄入量为200国际单位,51岁至70岁的人每日应摄入400国际单位,而70岁以上的人每日应摄入600国际单位。加兰表示,他也惊讶于可有效预防癌症的维生素D摄入量远远高于此前的推荐标准。
目前,研究人员对大剂量摄入维生素D是否会对身体产生副作用尚无定论。
相关研究成果发表在新一期《抗肿瘤研究》杂志上。(生物谷Bioon.com)
生物谷推荐原文出处:
Anticancer Research, 2011; 31: 607-612
Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention
CEDRIC F. GARLAND, CHRISTINE B. FRENCH, LEO L. BAGGERLY, ROBERT P. HEANEY
Abstract
Abstract. Background: Studies indicate that intake of vitamin D in the range from 1,100 to 4,000 IU/d and a serum 25- hydroxyvitamin D concentration [25(OH)D] from 60-80 ng/ml may be needed to reduce cancer risk. Few community-based studies allow estimation of the dose–response relationship between oral intake of vitamin D and corresponding serum 25(OH)D in the range above 1,000 IU/d. Materials and Methods: A descriptive study of serum 25(OH)D concentration and self-reported vitamin D intake in a community-based cohort (n=3,667, mean age 51.3±13.4 y). Results: Serum 25(OH)D rose as a function of self-reported vitamin D supplement ingestion in a curvilinear fashion, with no intakes of 10,000 IU/d or lower producing 25(OH)D values above the lower-bound of the zone of potential toxicity (200 ng/ml). Unsupplemented all-source input was estimated at 3,300 IU/d. The supplemental dose ensuring that 97.5% of this population achieved a serum 25(OH)D of at least 40 ng/ml was 9,600 IU/d. Conclusion: Universal intake of up to 40,000 IU vitamin D per day is unlikely to result in vitamin D toxicity.