title: Folic acid supplementation lowers blood arsenic.
abstract: BACKGROUND
  Chronic arsenic exposure currently affects >100 million persons worldwide. Methylation of ingested inorganic arsenic (InAs) to monomethylarsonic (MMAs) and dimethylarsinic (DMAs) acids relies on folate-dependent one-carbon metabolism and facilitates urinary arsenic elimination.
  
  
  OBJECTIVE
  We hypothesized that folic acid supplementation to arsenic-exposed Bangladeshi adults would increase arsenic methylation and thereby lower total blood arsenic.
  
  
  METHODS
  In this randomized, double-blind, placebo-controlled trial, we evaluated blood concentrations of total arsenic, InAs, MMAs, and DMAs in 130 participants with low plasma folate (<9 nmol/L) before and after 12 wk of supplementation with folic acid (400 microg/d) or placebo.
  
  
  RESULTS
  MMAs in blood was reduced by a mean +/- SE of 22.24 +/- 2.86% in the folic acid supplementation group and by 1.24 +/- 3.59% in the placebe group (P < 0.0001). There was no change in DMAs in blood; DMAs is rapidly excreted in urine as evidenced by an increase in urinary DMAs (P = 0.0099). Total blood arsenic was reduced by 13.62% in the folic acid supplementation group and by 2.49% in the placebo group (P = 0.0199).
  
  
  CONCLUSIONS
  Folic acid supplementation to participants with low plasma concentrations of folate lowered blood arsenic concentrations, primarily by decreasing blood MMAs and increasing urinary DMAs. Therapeutic strategies to facilitate arsenic methylation, particularly in populations with folate deficiency or hyperhomocysteinemia or both, may lower blood arsenic concentrations and thereby contribute to the prevention of arsenic-induced illnesses.
authors.affiliation: Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA. mvg7@columbia.edu
authors.forename: Mary V
authors.initials: MV
authors.lastname: Gamble
authors.forename: Xinhua
authors.initials: X
authors.lastname: Liu
authors.forename: Vesna
authors.initials: V
authors.lastname: Slavkovich
authors.forename: J Richard
authors.initials: JR
authors.lastname: Pilsner
authors.forename: Vesna
authors.initials: V
authors.lastname: Ilievski
authors.forename: Pam
authors.initials: P
authors.lastname: Factor-Litvak
authors.forename: Diane
authors.initials: D
authors.lastname: Levy
authors.forename: Shafiul
authors.initials: S
authors.lastname: Alam
authors.forename: Mominul
authors.initials: M
authors.lastname: Islam
authors.forename: Faruque
authors.initials: F
authors.lastname: Parvez
authors.forename: Habibul
authors.initials: H
authors.lastname: Ahsan
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Graziano
mesh_terms: D001151:Arsenic / Q000097:blood / Q000378:metabolism* / Q000652:urine; D001152:Arsenicals / Q000378:metabolism / Q000652:urine; D001459:Bangladesh / Q000453:epidemiology; D019587:Dietary Supplements; D004311:Double-Blind Method; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008745:Methylation / Q000187:drug effects*; D008875:Middle Aged; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D014874:Water Pollutants, Chemical / Q000097:blood / Q000378:metabolism* / Q000652:urine
chemical_list: D001152:Arsenicals; D014874:Water Pollutants, Chemical; D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid; C020300:monomethylarsonic acid; D001151:Arsenic