Vitamin tidak mencegah kanker

Suplemen vitamin dianggap berperan penting untuk mencegah kanker.

 

Penelitian yang dilakukan terhadap >5000 wanita berusia >42 tahun selama >7 tahun, membandingkan secara random efek suplementasi vitamin (folat, vitamin B6 dan vitamin B12) terhadap plasebo, membuktikan bahwa pemberian folat, vitamin B6 dan vitamin B12 tidak signifikan mencegah kanker.

 

Abstrak

 

Effect of Combined Folic Acid, Vitamin B₆, and Vitamin B₁₂ on Cancer Risk in Women

A Randomized Trial

Shumin M. Zhang, MD, ScD; Nancy R. Cook, ScD; Christine M. Albert, MD, MPH; J. Michael Gaziano, MD, MPH; Julie E. Buring, ScD; JoAnn E. Manson, MD, DrPH

JAMA. 2008;300(17):2012-2021.

Context  Folate, vitamin B₆, and vitamin B₁₂ are thought to play an important role in cancer prevention.

Objective  To evaluate the effect of combined folic acid, vitamin B₆, and vitamin B₁₂ treatment on cancer risk in women at high risk for cardiovascular disease.

Design, Setting, and Participants  In the Women's Antioxidant and Folic Acid Cardiovascular Study, 5442 US female health professionals aged 42 years or older, with preexisting cardiovascular disease or 3 or more coronary risk factors, were randomly assigned to receive either a daily combination of folic acid, vitamin B₆, and vitamin B₁₂ or a matching placebo. They were treated for 7.3 years from April 1998 through July 31, 2005.

Intervention  Daily supplementation of a combination of 2.5 mg of folic acid, 50 mg of vitamin B₆, and 1 mg of vitamin B₁₂ (n = 2721) or placebo (n = 2721).

Main Outcome Measures  Confirmed newly diagnosed total invasive cancer or breast cancer.

Results  A total of 379 women developed invasive cancer (187 in the active treatment group and 192 in the placebo group). Compared with placebo, women receiving the active treatment had similar risk of developing total invasive cancer (101.1/10 000 person-years for the active treatment group vs 104.3/10 000 person-years for placebo group; hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.79-1.18; P = .75), breast cancer (37.8/10 000 person-years vs 45.6/10 000 person-years, respectively; HR, 0.83; 95% CI, 0.60-1.14; P = .24), or any cancer death (24.6/10 000 person-years vs 30.1/10 000 person-years, respectively; HR, 0.82; 95% CI, 0.56-1.21; P = .32).

Conclusion  Combined folic acid, vitamin B₆, and vitamin B₁₂ treatment had no significant effect on overall risk of total invasive cancer or breast cancer among women during the folic acid fortification era.