High serum folate might have a potential dual effect on risk of colorectal cancer

Serum folate concentrations and all-cause, cardiovascular disease and cancer mortality: A cohort study based on 1999–2010 National Health and Nutrition Examination Survey (NHANES)

“…Furthermore, the effects of folate on cancer could vary substantially by cancer types and sites. For instance, a meta-analysis revealed a nonsignificant association between higher blood folate status and breast cancer mortality [29], whereas a recent case-control study identified persons with higher serum folate concentrations (N 23.61 ng/mL) who are at a 4.86-fold risk of colorectal cancer in comparison with those at lower folate levels (≤8.86 ng/mL) [30].…”

Modification of the Associations Between Duration of Oral Contraceptive Use and Ovarian, Endometrial, Breast, and Colorectal Cancers

“…20,21 Both OC use and alcohol consumption can decrease folate levels, but research suggests that folate reduces or increases risk for colorectal cancer depending on the presence of polyps, so the timing of these exposures may be integral in carcinogenesis. [22][23][24][25]…”

Colorectal polyp risk is linked to an elevated level of homocysteine

“…We also observed the different reports in distinct populations. For instance, the high level of folate was reported to be associated with the increased risk of CRC patients with adenomatous polyps, but not in CRC patients without adenomatous polyps in a Chinese population [ 25 ]. The evaluated plasma homocysteine level was associated with an increased susceptibility to colorectal polyps in Chinese population [ 26 ].…”