Consumption of folate-related nutrients and metabolism of arsenic in Bangladesh.
BACKGROUND
Inorganic arsenic (InAs) is metabolized to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and this methylation facilitates urinary arsenic excretion. Previous studies suggest that persons with more complete methylation, characterized as greater proportions of DMA and lesser proportions of MMA and InAs in urine, have a lower risk of adverse arsenic-related health outcomes.


OBJECTIVE
The purpose of this study was to examine whether the capacity to methylate arsenic differs by nutrient intake.


METHODS
Participants were 1016 Bangladeshi adults exposed to arsenic in drinking water. Nutrient intake was assessed with a validated food-frequency questionnaire. Multivariate regression analyses were used to examine associations of nutrients with urinary arsenic metabolite profiles.


RESULTS
In multivariate analyses, higher intakes of cysteine, methionine, calcium, protein, and vitamin B-12 were associated with lower percentages of InAs and higher ratios of MMA to InAs in urine. Higher intakes of niacin (beta=0.22, P=0.02) and choline (beta=0.10, P=0.02) were associated with higher DMA-to-MMA ratios, after adjustment for age, sex, smoking, total urinary arsenic, and total energy intake.


CONCLUSIONS
Findings from the current study show the influence of multiple nutrients on arsenic methylation. In particular, this study highlights the potential importance of dietary intakes of cysteine, methionine, niacin, vitamin B-12, and choline on health effects of arsenic by modulating its metabolism.
Heck
Julia E
JE
Department of Epidemiology, Mailman School of Public Health and Institute for Social and Economic Research and Policy, Columbia University, New York, NY, USA.
Gamble
Mary V
MV
Chen
Yu
Y
Graziano
Joseph H
JH
Slavkovich
Vesna
V
Parvez
Faruque
F
Baron
John A
JA
Howe
Geoffrey R
GR
Ahsan
Habibul
H
D000328:Adult; D001151:Arsenic / Q000378:metabolism* / Q000652:urine; D001152:Arsenicals / Q000378:metabolism / Q000652:urine; D001459:Bangladesh; D002101:Cacodylic Acid / Q000378:metabolism / Q000652:urine; D002794:Choline / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism* / Q000652:urine; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D005492:Folic Acid / Q000378:metabolism*; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism; D008745:Methylation / Q000187:drug effects*; D008875:Middle Aged; D015999:Multivariate Analysis; D009525:Niacin / Q000378:metabolism; D011795:Surveys and Questionnaires; D014805:Vitamin B 12 / Q000378:metabolism; D014803:Vitamin B Complex / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000652:urine
D001152:Arsenicals; D004044:Dietary Proteins; D014874:Water Pollutants, Chemical; D014803:Vitamin B Complex; D009525:Niacin; D005492:Folic Acid; D008715:Methionine; D002101:Cacodylic Acid; C020300:monomethylarsonic acid; D003545:Cysteine; D001151:Arsenic; D002794:Choline; D014805:Vitamin B 12