|
Evidence from observational studies suggests that inadequate folate status enhances colorectal carcinogenesis, but results from some randomized trials do not support this hypothesis.
Dr Ku and colleagues from Massachussetts, USA assessed the effect of folic acid supplementation on recurrent colorectal adenoma.
The research team conducted a cost-efficient, double-blind, randomized trial among participants of 2 large prospective cohorts, the Health Professionals Follow-Up Study and the Nurses’ Health Study.
Participants were randomly assigned to receive folic acid (1 mg/d) or placebo for 3 to 7 years.
The primary endpoint was any new diagnosis of adenoma during the study period of 1996 to 2004.
Secondary outcomes were adenoma by site and stage and number of recurrent adenomas.
 | | Adenoma recurrence decreased after folic acid in those with low baseline levels | | American Journal of Clinical Nutrition |
The research team examined associations by plasma folate concentrations at baseline.
The team found that the incidence of at least one recurrent adenoma was not significantly associated with folic acid supplementation.
Among participants with low plasma folate concentrations at baseline, and those randomly assigned to receive folic acid experienced a significant decrease in adenoma recurrence.
However, subjects with high folate concentrations at baseline, supplemental folic acid had no significant effect.
Contrary to findings from another clinical trial, the research team found no evidence for an increased risk of advanced or multiple adenomas.
Dr Ku's team concludes, "Our results do not support an overall protective effect of folic acid supplementation on adenoma recurrence."
"Folic acid supplementation may be beneficial among those with lower folate concentrations at baseline."
| 
Email this page to a colleague
