METALLOPATHY Evidence on heavy metals in people

Static evidence pages. Grades A to F. Sources named.

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Detox and binders

Does folic acid change arsenic methylation?

Two randomized trials found that folic acid increased the percentage of urinary arsenic excreted as dimethylarsinic acid, a methylation product. In the larger trial, 800 µg/day lowered blood arsenic and 400 µg/day did not. This is evidence about arsenic methylation, not evidence that folic acid removes stored arsenic or treats arsenicosis.

Trials

Folic acid trials with an arsenic outcome. Doses are what the trials used, not a recommendation.
StudyDesignResult
Gamble 2006 RCT, 12 weeks, 200 folate-deficient adults in Bangladesh Urinary percent DMA rose from 72 to 79 percent versus placebo (P<0.0001). PMID 17093162.
Peters 2015 FACT RCT, 24 weeks, 622 arsenic-exposed adults in Bangladesh, mostly folate sufficient 800 µg/day lowered blood arsenic. 400 µg/day did not. PMID 25978852.
Bozack 2019 Same FACT trial Folic acid increased percent DMA, with rebound after stopping. PMID 30590411. Not an independent replication.

Related pages

Sources

  1. Gamble et al. 2006, doi:10.1093/ajcn/84.5.1093, PMID 17093162
  2. Peters et al. 2015, doi:10.1289/ehp.1409396, PMID 25978852
  3. Bozack et al. 2019, doi:10.1093/ajcn/nqy148, PMID 30590411

Heavy Metal Index

Heavy Metal Index: Arsenic. This Heavy Metal Index URL returned HTTP 200 on 15 October 2026. Figures on this page are not copied from that index. They come from the sources named above.

What's safe to buy

The Heavy Metal Tested and Certified public register listed no licensees on 15 October 2026. That page reported 0 certified brands and 0 certified products, and it stated that no brand has completed the three-lot baseline. A specimen layout on the register is an illustration, not a licensee. This page does not name or rank any brand.

The program states that certification is a measurement of a product against a published limit, not a statement that the product is safe. If a licensee is later listed for this category, it will be on the register.

This page summarizes cited documents. It does not diagnose or prescribe. Reviewed 15 October 2026.