Folic acid (FA) supplementation facilitates urinary excretion of arsenic, a human carcinogen. A better understanding of interactions between one-carbon metabolism intermediates may improve the ability to design nutrition interventions that further facilitate arsenic excretion.Objective:
The objective was to determine if FA and/or creatine supplementation increase choline and betaine and decrease dimethylglycine (DMG).Methods:
We conducted a secondary analysis of the Folic Acid and Creatine Trial, a randomized trial in arsenic-exposed Bangladeshi adults (n = 605, aged 24-55 y, 50.3% male) who received arsenic-removal water filters. We examined treatment effects of FA and/or creatine supplementation on plasma choline, betaine, and DMG concentrations, measured by LC-tandem mass spectrometry at baseline and at week 12. Group comparisons were between 1) 400 and 800 μg FA/d (FA400 and FA800, respectively) compared with placebo, 2) creatine (3 g/d) compared with placebo, and 3) creatine plus FA400 compared with FA400.Results:
Choline decreased in the placebo group (−6.6%; 95% CI: −10.2%, −2.9%) but did not change in the FA groups (FA400: 2.5%; 95% CI: −0.9%, 6.1%; FA800: 1.4%; 95% CI: −2.5%, 5.5%; P < 0.05). Betaine did not change in the placebo group (−3.5%; 95% CI: −9.3%, 2.6%) but increased in the FA groups (FA400: 14.1%; 95% CI: 9.4%, 19.0%; FA800: 13.0%; 95% CI: 7.2%, 19.1%; P < 0.01). The decrease in DMG was greater in the FA groups (FA400: −26.7%; 95% CI: −30.9%, −22.2%; FA800: −27.8%; 95% CI: −31.8%, −23.4%) than in the placebo group (−12.3%; 95% CI: −18.1%, −6.2%; P < 0.01). The percentage change in choline, betaine, and DMG did not differ between creatine treatment arms and their respective reference groups.Conclusion:
Supplementation for 12 wk with FA, but not creatine, increases plasma betaine, decreases plasma DMG, and prevents a decrease in plasma choline in arsenic-exposed Bangladeshi adults. This trial was registered at clinicaltrials.gov as NCT01050556. J Nutr 2016;146:1062-7.