Folate and the risk of colorectal, breast and cervix cancer: the epidemiological evidence.

摘要: It is only recently that folate deficiency has been implicated in the development of cancer. The mechanisms by which might protect against cancer are not clear but may relate to its role DNA methylation and synthesis. All case-control, cohort intervention trials reported English, French, or German, on intake blood levels relation risk colorectal, breast, cervix were reviewed. Twenty 12 nested case-control studies identified. epidemiological consistently show an inverse association between and/or frequency colorectal carcinomas, less clearly adenomas. Long-term use supplements seems be greater benefit than dietary intake. effect modulated alcohol, methionine, MTHFR polymorphisms. Results from animal suggest supplementation decrease increase depending dosage timing. Recent also breast among women who regularly consume alcohol. Conversely, evidence remains uncertain for cervical prevention; results two rates intraepithelial neoplasia regression progression negative. An later carcinogenesis supported few (nested) invasive Some conflicting due fact do accurately reflect concentrations cells origin. Furthermore, a have taken into account modulating polymorphisms their analyses. observed associations cancer, other hand, confounded various factors, especially potentially protective constituents fruits vegetables. Ongoing can strengthen causality excluding such confounding, optimal dose, duration, stage appropriate (genetically predisposed) study group chemoprevention yet defined.