Heck Julia E, Gamble Mary V, Chen Yu, Graziano Joseph H, Slavkovich Vesna, Parvez Faruque, Baron John A, Howe Geoffrey R, Ahsan Habibul
Department of Epidemiology, Mailman School of Public Health and Institute for Social and Economic Research and Policy, Columbia University, New York, NY, USA.
Am J Clin Nutr. 2007 May;85(5):1367-74. doi: 10.1093/ajcn/85.5.1367.
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.
The purpose of this study was to examine whether the capacity to methylate arsenic differs by nutrient intake.
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.
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.
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.
无机砷（InAs）会代谢为一甲基砷酸（MMA）和二甲基砷酸（DMA），这种甲基化作用有助于砷通过尿液排出。先前的研究表明，甲基化更完全的人，其尿液中DMA的比例更高，MMA和InAs的比例更低，这类人发生砷相关不良健康结局的风险较低。
本研究旨在探讨砷的甲基化能力是否因营养摄入情况而异。
研究对象为1016名饮用含砷水的孟加拉国成年人。通过一份经验证有效的食物频率问卷评估营养摄入情况。采用多变量回归分析来研究营养物质与尿砷代谢产物谱之间的关联。
在多变量分析中，较高的半胱氨酸、蛋氨酸、钙、蛋白质和维生素B-12摄入量与尿液中较低的InAs百分比以及较高的MMA与InAs比值相关。在对年龄、性别、吸烟状况、尿砷总量和总能量摄入进行调整后，较高的烟酸摄入量（β=0.22，P=0.02）和胆碱摄入量（β=0.10，P=0.02）与较高的DMA与MMA比值相关。
本研究结果显示了多种营养物质对砷甲基化的影响。特别是，本研究强调了通过调节砷的代谢，饮食中摄入半胱氨酸､蛋氨酸､烟酸､维生素B-12和胆碱对砷的健康影响可能具有重要意义。
