Does Folic Acid Cause Colon Cancer?

· Folic Acid (folate) is important in fetal development and deficiencies in folic acid are associated with Spinal Bifida. · The United States and Canada started mandatory programs to add folic acid to wheat flour in 1997.
· Chile started a similar program in 2000 and according to data recently published in the European journal of gastroenterology & hepatology, there might be an association between the supplementation of folic acid and colon cancer.
· According to the study, reported cases of colon cancer increased by up to 190% during the four years after the start of the folic acid program.
· The was an observational study with many statistical weaknesses. There are many factors that could explain this increase in colon cancer in Chile.
· The question of colon cancer and folic acid supplementation was first raised in 2007 when a study was published in the journal Cancer Epidemiol Biomarkers Prevention. The study authors stated that the frequency of colon cancer started to climb in 1996 and peaked in 1998. This study was also observational and it is difficult to make a conclusion based on it alone.
· The rise and peak of colon cancer would appear to be too close to the start of the folic acid program for there to be a connection.
· Colonoscopy screening for colon cancer has also increased, which would correspond to more cases being diagnosed over a shorter period of time, creating a selection bias over this time.
· It is more likely that folic acid protects against cancer rather than causing it. There is research which shows this benefit.
· The Nurses’ Health Study showed that Folic Acid supplementation was associated with a lower incidence of colon cancer.
· In conclusion, the above study is at the very least controversial and more likely incorrect.

Reference
Eur J Gastroenterol Hepatol. PMID: 19190501
Multivitamin use, folate, and colon cancer in women in the nurses’ health study. Ann Intern Med 1998;129:517-24

April 14th 2009

Posted on April 14, 2009

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