Dietary Folate Consumption and Breast Cancer Risk

Open Access
Publisher Website
Google Scholar
Abstract
Deficient dietary folate intake may predispose individuals to cancer as a consequence of disruption of DNA synthesis, repair, and methylation (1,2); diets deficient in methyl groups may result in the activation of oncogenes and inactivation of tumor suppressor genes (3). Relatively low intake of methionine and relatively high intake of alcohol may increase folate requirements, the former by reducing the availability of methyl groups (4) and the latter by interfering with folate metabolism (5). Epidemiologic evidence linking dietary folate, methionine, and alcohol intake with cancer risk is limited. Two prospective studies (6,7) showed that diets low in folate and methionine and high in alcohol were associated with increased risk of colorectal adenomas and of colon cancer, respectively. Another prospective study (8) showed an increased risk of recurrence of colorectal adenoma in association with a high-alcohol, low-folate diet, and a case-control study (9) showed an increased risk of rectal cancer in association with a low-folate, high-alcohol dietary combination. A recent prospective study (10) showed some evidence for an inverse association between folate intake and breast cancer risk in women with relatively high alcohol intake; alcohol consumption by itself has been associated with an increased breast cancer risk (11). Given the paucity of currently available prospective data, we examined the association between dietary folate intake and breast cancer risk and its modification by methionine and alcohol intake in a cohort study in Canada.