Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Mar;116(3):315-21.
doi: 10.1289/ehp.10639.

Nutritional status has marginal influence on the metabolism of inorganic arsenic in pregnant Bangladeshi women

Li Li  1 , Eva-Charlotte Ekström, Walter Goessler, Bo Lönnerdal, Barbro Nermell, Mohammad Yunus, Anisur Rahman, Shams El Arifeen, Lars Ake Persson, Marie Vahter
Affiliations

Nutritional status has marginal influence on the metabolism of inorganic arsenic in pregnant Bangladeshi women

Li Li et al. Environ Health Perspect. 2008 Mar.

Abstract

Background: The interindividual variation in metabolism of inorganic arsenic (iAs), involving methylation via one-carbon metabolism, has been well documented, but the reasons remain unclear.

Objectives: In this population-based study we aimed to elucidate the effect of nutrition on As methylation among women in Matlab, Bangladesh, where people are chronically exposed to iAs via drinking water.

Methods: We studied effects of macronutrient status using body mass index (BMI) among 442 women in early pregnancy (gestational week 8), and effects of micronutrient status (plasma folate, vitamin B12, zinc, ferritin, and selenium) among 753 women at gestational week 14. Arsenic metabolites in urine were measured by HPLC combined with hydride generation inductively coupled plasma mass spectrometry.

Results: The median concentration of As in urine was 97 microg/L (range, 5-1,216 microg/L, adjusted by specific gravity). The average proportions of iAs, monomethylarsonic acid, and dimethylarsinic acid in urine in gestational week 8 were 15%, 11%, and 74%, respectively. Thus, the women had efficient As methylation in spite of being poorly nourished (one-third had BMIs < 18.5 kg/m2) and having elevated As exposure, both of which are known to decrease As methylation. The metabolism of iAs was only marginally influenced by micronutrient status, probably because women, especially in pregnancy and with low folate intake, have an efficient betaine-mediated remethylation of homocysteine, which is essential for an efficient As methylation.

Conclusions: In spite of the high As exposure and prevalent malnutrition, overall As methylation in women in early pregnancy was remarkably efficient. The As exposure level had the greatest impact on As methylation among the studied factors.

Keywords: arsenic; metabolite; methylation; nutrition; pregnant women; urine.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Overview of one-carbon metabolism and the methylation of As. Abbreviations: 5,10-CH2-THF, methylene tetrahydrofolate; AS3MT, As methyltransferase; DMG, dimethylglycine; GAA, guanidinoacetate; MTHFR, 5,10-CH2-THF reductase; SAH, S-adenosylhomocysteine; THF, tetrahydrofolate. Methionine, which originates from dietary protein and tissue protein, is activated by methionine adenosyltransferase to form SAM, which provides methyl groups for most methylation reactions in the body (e.g., methylation of DNA, GAA to creatine, and iAs to MMA and DMA). Methyltransferases are required for the methylation reactions, in which SAH is formed. SAH is hydrolyzed to homocysteine, which is used either for regeneration of methionine or for glutathione (GSH) biosynthesis in a transsulfuration pathway. In one methionine regeneration pathway, the methyl group is transferred to homocysteine from 5-CH3-THF and catalyzed by vitamin B12. In the alternate pathway, the methyl group is transferred from betaine and catalyzed by betaine:homocysteine methyltransferase (BHMT).
Figure 2
Figure 2
Selection of participants to studies of effects of macronutrient and micronutrient status on As metabolism.
Figure 3
Figure 3
Frequency distribution of As metabolites in urine, demonstrating the interindividual variability in As metabolism among 442 pregnant women in GW8.
See this image and copyright information in PMC

Comment in

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Ahsan H, Chen Y, Kibriya MG, Slavkovich V, Parvez F, Jasmine F, et al. Arsenic metabolism, genetic susceptibility, and risk of premalignant skin lesions in Bangladesh. Cancer Epidemiol Biomarkers Prev. 2007;16(6):1270–1278. - PubMed
    1. Akesson A, Berglund M, Schütz A, Bjellerup P, Bremme K, Vahter M. Cadmium exposure in pregnancy and lactation in relation to iron status. Am J Public Health. 2002;92:284–287. - PMC - PubMed
    1. BGS. Arsenic Contamination of Groundwater in Bangladesh. Volume 2: Final Report. Keyworth, UK: British Geological Survey, Natural Environment Research Council, Department for International Development, Government of the People’s Republic of Bangladesh; 2001. [[accessed 28 January 2008]]. Available: http://www.bgs.ac.uk/arsenic/Bangladesh/Reports/ExecSummary.pdf.
    1. Bredfeldt TG, Jagadish B, Eblin KE, Mash EA, Gandolfi AJ. Monomethylarsonous acid induces transformation of human bladder cells. Toxicol Appl Pharmacol. 2006;216(1):69–79. - PMC - PubMed
    1. Chakraborti D, Sengupta MK, Rahman MM, Ahamed S, Chowdhury UK, Hossain MA, et al. Groundwater arsenic contamination and its health effects in the Ganga-Meghna-Brahmaputra plain. J Environ Monit. 2004;6(6):74N–83N. - PubMed

Publication types

MeSH terms

-