Anetor John I, Wanibuchi Hideki, Fukushima Shoji
Department of Pathology, Osaka City University Medical School of Medicine, Osaka 545-8585 Japan.
Asian Pac J Cancer Prev. 2007 Jan-Mar;8(1):13-23.
Arsenic (As) is a ubiquitous metalloid found in several forms in food and the environment, such as the soil, air and water. The predominant form is inorganic arsenic in drinking water, which is both highly toxic and carcinogenic and rapidly bioavailable. As is currently one of the most important environmental global contaminants and toxicants, particularly in the developing countries. For decades, very large populations have been and are currently still exposed to inorganic As through geogenically contaminated drinking water. An increased incidence of disease mediated by this toxicant is the consequence of long-term exposure. In humans, chronic ingestion of inorganic arsenic (> 500 mg/L As) has been associated with cardiovascular, nervous, hepatic and renal diseases and diabetes mellitus as well as cancer of the skin, bladder, lung, liver and prostate. Contrary to the earlier view that methylated compounds are innocuous, the methylated metabolites are now recognized to be both toxic and carcinogenic, possibly due to genotoxicity, inhibition of antioxidative enzyme functions, or other mechanisms. As inhibits indirectly sulfhydryl containing enzymes and interferes with cellular metabolism. Effects involve such phenomena as cytotoxicity, genotoxicity and inhibition of enzymes with antioxidant function. These are all related to nutritional factors directly or indirectly. Nutritional studies both in experimental and epidemiological studies provide convincing evidence that nutritional intervention, including chemoprevention, offers a pragmatic approach to mitigate the health effects of arsenic exposure, particularly cancer, in the relatively resource-poor developing countries. Nutritional intervention, especially with micronutrients, many of which are antioxidants and share the same pathway with As, appears a host defence against the health effects of arsenic contamination in developing countries and should be embraced as it is pragmatic and inexpensive.
砷（As）是一种普遍存在的类金属，在食物和环境中以多种形式存在，如土壤、空气和水中。饮用水中主要的形式是无机砷，它具有高毒性和致癌性，且生物可利用性高。砷是目前全球最重要的环境污染物和有毒物质之一，尤其是在发展中国家。几十年来，大量人群过去一直且目前仍通过地质污染的饮用水接触无机砷。长期接触这种有毒物质会导致疾病发病率上升。在人类中，长期摄入无机砷（>500毫克/升砷）与心血管、神经、肝脏和肾脏疾病、糖尿病以及皮肤、膀胱、肺、肝脏和前列腺癌有关。与早期认为甲基化化合物无害的观点相反，现在人们认识到甲基化代谢产物既有毒又致癌，可能是由于基因毒性、抗氧化酶功能抑制或其他机制。砷间接抑制含巯基的酶并干扰细胞代谢。其影响包括细胞毒性、基因毒性和对具有抗氧化功能的酶的抑制等现象。这些都直接或间接地与营养因素有关。实验研究和流行病学研究中的营养研究都提供了令人信服的证据，表明营养干预，包括化学预防，为减轻砷暴露对健康的影响，特别是在资源相对匮乏的发展中国家减轻癌症影响，提供了一种切实可行的方法。营养干预，特别是使用微量营养素，其中许多是抗氧化剂且与砷有相同的作用途径，似乎是发展中国家抵御砷污染对健康影响的一种宿主防御机制，因其切实可行且成本低廉而应被采用。
