Dietary vitamin B9 (folate) protects against the development of colon cancer, says a new study.
In the prospective cohort study of 56,332 participants aged 50–64 years, information on diet, supplements and lifestyle was collected through questionnaires (1). 465 Colon and 283 rectal cancer cases were identified during an average follow-up time of 10.6 years. Incidence rate ratios of colon and rectal cancers related to micronutrient intake were calculated. The study found a protective effect of dietary folate (mean intake of 350.7 micrograms/day) but not supplemental vitamin B9 (folic acid) on colon cancer.
Vitamin C, vitamin E and beta-carotene showed no relation with colorectal cancer. Rectal cancer did not seem associated with any micronutrient. For both colon and rectal cancer, the researchers found an interaction between dietary folate and alcohol intake, with a significant, preventive effect among those consuming above 10 g alcohol/day only.
In the past, studies with dietary folate and folic acid in supplements and fortification on colorectal cancer have found contradicting results suggesting source-specific effects. Further studies should thus take source into account, the researchers commented.