Another Report on the Dangers of Vitamins

March 18, 2009 at 1:50 pm (Nutritionism, Supplements) (, , , , )

A submission to the Journal of the National Cancer Institute has warned that Folic Acid supplementation is associated with increased risk of prostate cancer. This has been reported by just a handful of news outlets – mostly online-only, US-based outlets. Here’s what the authors found:

Among the 643 men who were randomly assigned to placebo or supplementation with folic acid, the estimated probability of being diagnosed with prostate cancer over a 10-year period was 9.7% (95% confidence interval [CI] = 6.5% to 14.5%) in the folic acid group and 3.3% (95% CI = 1.7% to 6.4%) in the placebo group (age-adjusted hazard ratio = 2.63, 95% CI = 1.23 to 5.65, Wald test P = .01).

The authors do state that the estimates of prostate cancer risk in the placebo and folic acid groups should be interpreted with caution due to the small number of prostate cancers in this study, but it doesn’t look good for Folic Acid supplements. By contrast, according to the authors of this paper, baseline dietary folate was inversely associated with prostate cancer risk. My advice? Eat food. Not too much. Mostly plants. And ditch the dietary supplements.

This isn’t the first time that the wisdom of using food supplements has been called into question. You may remember the BMJ study on Calcium supplements that found they may increase the risk of heart attacks among older women (pdf). You may also remember the JAMA antioxidant studies that were criticised by HSIS – and the Cochrane review of antioxidants that was criticised by the HFMA and Cliff Richard. Negative reports keep on appearing and (when they appear in the mainstream media) the $60bn food supplement pill industry keep on trying to counter them with PR interventions from industry groups such as HSIS and HFMA.

Links

News coverage; abstract; more negative reports on supplements (an old blog post – includes discussion of the BMJ Calcium/cancer paper).

4 Comments

  1. dvnutrix said,

    There are several cheerful studies that suggest that supplementation might be linked to increased levels of colon or rectal cancer (folic acid – colon in men and women, B6 – rectal in women).

    Supplementation – as you say, it goes to show you can’t be too careful.

  2. New government brochure explains climate science (AP) — But As For Me said,

    […] Another Report on the Dangers of Vitamins « jdc325’s Weblog […]

  3. Neuroskeptic said,

    But…I thought vitamins were natural, and therefore, good?

  4. Sceric said,

    @ Neuroskeptic

    no, the natural thingies are the minerals…and I tell you they hurt, when somebody puts a 1t big bag on your toes…so probably dangerous too

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