B vitamins and folic acid do not reduce colorectal adenoma risk


B vitamins and folic acid do not reduce colorectal adenoma risk

Taking the supplement combo of vitamins B6, B12 and folic acid has no impact on colorectal adenoma risk in females at high risk of cardiovascular disease, researchers from Harvard Medical School in Boston reported in the Journal of the National Cancer Institute, October 12th issue.

Dietary supplements are extremely popular throughout the world, and especially in the USA. According to some studies, between 28% and 35% of Americans said they take dietary supplements which contain vitamins B6, B12 and folic acid.

Prior animal studies have demonstrated that B vitamins help fight colorectal carcinogenesis (initiation cancer formation). Some epidemiologic studies had indicated that those consuming the most folate had a 20% to 40% lower-than-average risk of developing colorectal cancer.

However, the vast majority of studies have concentrated on the benefits of just folic acid supplementation.

Yiqing Song, M.D., Sc.D. and team set out to find out what the impact of taking vitamins B6, B12 and folic acid supplements might be on colorectal adenoma risk.

Colorectal adenomas are benign tumors. Although they may be benign, they can eventually become malignant over time. When they become malignant they are called adenocarcinomas. Even during their benign state they can still cause serious health problems by pushing against other structures.

In this study, the team carried out a study in WAFACS (the Women's Antioxidant and Folic Acid Cardiovascular Study). This randomized, double-blind, placebo-controlled study involved 5,442 female health care professionals who were deemed to be at high risk of cardiovascular disease.

The study lasted from April 1998 to July 2005. The women were randomly selected into one of two groups:

  • The combination supplement group - they were given vitamins B6, B12 and folic acid
  • The placebo group
A follow-up endoscopy during the 9.2 year monitoring period was performed on 1,470 of the participants.

Vitamins B6, B12 and folic acid made no significant difference to adenoma risk

The authors found no statistically significant change in the risk of developing colorectal adenoma between the young women in the two groups, i.e. the vitamin B6, B12 and folic combo supplementation does not appear to reduce colorectal adenoma incidence.

The researchers wrote:

"Our findings do not support recommending B-vitamin supplementation for the prevention of colorectal adenomas."

Dr. Song emphasized that further evidence is required to confirm the findings from this latest study. He added that alcohol consumption did not alter the impact the supplements had on their results. Alcohol is a known folate antagonist.

The findings are less relevant for malnourished people

Regina G. Ziegler, Ph.D., M.P.H., of the Division of Cancer Epidemiology and Genetics, wrote in an Accompanying Editorial in the same journal, explaining that the null results of this nine-year follow-up on young women taking a vitamin B6, B12 and folic supplement combination may be less relevant for people of both sexes with suboptimal micronutrient intake.

Ziegler wrote:

"Observational epidemiology results, from prospective studies of diet and supplements or of circulating biomarkers, are provocative and imply that the role of folate and other B vitamins in colorectal carcinogenesis merits continued exploration."

Other studies examining the impact on colorectal adenoma risk

Statins - researchers from Brigham and Women's Hospital and Harvard Medical School, Boston, Mass., USA found that statins did not protect patients against colorectal adenomas. They reported their findings in Cancer Prevention Research, April 2010 issue.

Aspirin - scientists from the Dartmouth Medical School in Lebanon, N.H. found that taking regular aspirin may reduce colorectal adenoma risk in patients with a genetic variant. Their research was published in the Journal of the National Cancer Institute, October 2006 issue.

Mythbusting: Vegetarians Don't Live Longer & Soy Decreases B12 (by WAPF) (Video Medical And Professional 2020).

Section Issues On Medicine: Disease