Bowel or colon cancer is one of the most common types of cancer, according to Cleveland Clinic. Dietary sources of folic acid, specifically lentils, may aid in colon cancer prevention. Scientific study results examining the link between folic acid and bowel cancer, however, have been confusing. While some show no benefit, others have suggested a link to increased risk of bowel cancer.
Link to Bowel Cancer
A study published in the July 2008 issue of the "Journal of Proteome Research" suggested that low levels of folic acid may increase the risk of DNA damage to colon cells and thereby promote bowel cancer development. Researchers showed that proteins associated with DNA repair, proliferation and cell death were all altered by folic acid deficiency. Specifically, the scientists showed that low folic acid levels altered the ability of proteins to stop the malignant transformation of colon cells into cancerous colon cells.
Lower Risk of Cancer
The December 2002 issue of the "International Journal of Cancer" included a study on the diets of an Italian population that investigated a possible link between dietary folic acid and bowel cancer risk. Researchers studied the diets of 1,953 patients with bowel cancer and more than 4,000 disease-free patients. Bowel cancer risk was 40 percent greater in those whose diets were deficient in folic acid. The main sources of folic acid in the Italian diets were green leafy vegetables, whole grains, and liver. Peas, beans and orange juice were also popular folic acid sources for the study group.
Too Much Folic Acid
The April 2009 issue of "Nutrition Reviews" examined the conflicting study outcomes regarding folic acid and bowel cancer. Researchers concluded that under most circumstances, an adequate intake of folic acid is protective against bowel cancer. In select situations in which an individual has pre-cancerous or cancerous tumors, however, too much consumption seems to promote the cancer's growth.
Alternative Explanation
Researchers reporting in the September 2009 issue of "European Journal of Clinical Nutrition" offer an alternative explanation. They examined the diets of a Korean population and found that women who consumed high amounts of dietary folic acid enjoyed a reduction in bowel cancer risk by as much as 70 percent. Dietary folic acid is found in its precursor form as folate in leafy green vegetables. Folate is synthesized by the body into folic acid, which is the vitamin's active form. The researchers hypothesized that only naturally occurring folic acid is beneficial, while laboratory synthesized folic acid may be harmful.
References
- Cleveland Clinic: Digestive Diseases: Diet Tips
- "Journal of Proteome Research"; The Response of Human Colonocytes to Folate Deficiency in Vitro: Functional and Proteomic Analyses; Susan Duthie et al.; July 2008
- "International Journal of Cancer"; Dietary Folate and Colorectal Cancer; Carlo La Vecchia et al.; December 2002
- "Nutrition Reviews"; Folate, Cancer Risk, and the Greek God, Proteus: a Tale of Two Chameleons; Joel Mason; April 2009
- "European Journal of Clinical Nutrition"; Folate Intake and the Risk of Colorectal Cancer in a Korean Population; Juou Kim; September 2009
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