title: Nutritional status has marginal influence on the metabolism of inorganic arsenic in pregnant Bangladeshi women.
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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Eva-Charlotte
authors.initials: EC
authors.lastname: Ekström
authors.forename: Walter
authors.initials: W
authors.lastname: Goessler
authors.forename: Bo
authors.initials: B
authors.lastname: Lönnerdal
authors.forename: Barbro
authors.initials: B
authors.lastname: Nermell
authors.forename: Mohammad
authors.initials: M
authors.lastname: Yunus
authors.forename: Anisur
authors.initials: A
authors.lastname: Rahman
authors.forename: Shams
authors.initials: S
authors.lastname: El Arifeen
authors.forename: Lars Ake
authors.initials: LA
authors.lastname: Persson
authors.forename: Marie
authors.initials: M
authors.lastname: Vahter
mesh_terms: D000328:Adult; D001151:Arsenic / Q000493:pharmacokinetics* / Q000633:toxicity / Q000652:urine; D020261:Arsenic Poisoning / Q000150:complications / Q000378:metabolism; D001459:Bangladesh / Q000453:epidemiology; D015992:Body Mass Index; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006306:Health Surveys; D006801:Humans; D044342:Malnutrition / Q000150:complications; D013058:Mass Spectrometry; D018811:Maternal Exposure / Q000009:adverse effects*; D008745:Methylation; D009752:Nutritional Status; D011247:Pregnancy; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics* / Q000633:toxicity / Q000652:urine
chemical_list: D014874:Water Pollutants, Chemical; D001151:Arsenic