抗氧化剂补充剂可降低全因和癌症死亡率 Antioxidant supplements may lower risk for all-cause and cancer mortality

Antioxidant supplements may lower risk for all-cause and cancer mortality

Vitamin/mineral supplementation, specifically taking antioxidant supplements, may reduce risk for cancer and all-cause mortality, according to a new study.

The study was based on data from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg).   For the study, 23,943 participants were recruited in 1994-1998 and they did not have pre-existing cancer and myocardial infarction/stroke at baseline.

During 11 years of follow-up, 1101 deaths were registered.  After adjusting for all potential confounders, use of vitamin/mineral supplements and multivitamin supplements at baseline was not associated significantly with cancer, cardiovascular or all-cause mortality.

However, taking antioxidant supplements such as vitamin C and vitamin E at baseline was associated with a 48% reduced risk for cancer mortality and a 42% reduced risk for all-cause mortality.

Still, compared to never users, those who started taking vitamin/mineral supplements during the follow-up were significantly 74% more likely to die from cancer and 58% more likely to die from all causes.     Does this mean that taking vitamin supplements increased the death risk?

Keep in mind that those who started taking vitamins after entering the study may be the patients who were newly diagnosed with cancer or other diseases.   That is, they died more likely because of their disease not because they started taking vitamin supplements.

The researchers noted that this increased risk for cancer death or all-cause death may be a sick-user effect, meaning that they died maybe because they were sick but not because they took vitamin supplements.

The interesting observation is that taking antioxidant supplements was associated with reduced risk of cancer mortality and all-cause mortality.

Another study reported earlier at jkzx.com suggests that antioxidants can help prevent cardiovascular disease.  This may explain why antioxidant supplements can reduce risk for all-cause mortality.

Reference

Alcindo Busanello, Nilda Berenice Vargas Barbosa, Luis Ricardo Peroza, Luana Echeverria Farias, Marilise Escobar Burger, Katia Padilha Barreto, Roselei Fachinetto, Vitamin/mineral supplementation and cancer, cardiovascular, and all-cause mortality in a German prospective cohort (EPIC-Heidelberg).  Eur J Nutr. 2011 Jul 22. Epub 2011 Jul 22. PMID: 21779961