Naughton Declan P, Nepusz Tamás, Petroczi Andrea
School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, UK.
Met Ions Life Sci. 2011;8:107-32.
In the present context, metal ions can be categorized into several classes including those that are essential for life and those that have no known biological function and thus can be considered only as potentially hazardous. Many complexities arise with regard to metal toxicity and there is a paucity of studies relating to many metals which are frequent components of the diet. For many people ingestion of mineral supplements is considered a risk-free health choice despite growing evidence to the contrary. Numerous approaches have been developed to assess risk associated with ingestion of metal ions. These include straightforward estimation of safe limits such as oral reference dose which are often based on data derived from animal experiments. More convoluted approaches such as the Target Hazard Quotient involve assessment of hazard with frequent exposure over long durations such as a lifetime. The latter calculation also affords facile consideration of the effects of many metals together. In many cases, rigorous data are unavailable, hence, large factors of uncertainty are employed to relate risk to humans. Owing to the nature of metal toxicity, data pertaining to the gastrointestinal tract and liver are often acquired from diseases of metal homeostasis or episodes of considerable metal overload. Whilst these studies provide evidence for mechanisms of metal-induced toxicity such as enhancing oxidative stress, extrapolation of these results to healthy individuals or patients with chronic inflammatory diseases is not straightforward. In summary, the diverse nature of metals and their effects on human tissues along with a paucity of studies on the full range of their effects, warrant further in-depth studies on the association of metals to ageing, chronic inflammatory diseases, and cancer.
在当前背景下，金属离子可分为几类，包括对生命至关重要的那些以及那些尚无已知生物学功能、因此只能被视为具有潜在危害的金属离子。金属毒性方面存在许多复杂情况，而且关于许多作为饮食常见成分的金属的研究很少。尽管越来越多的证据表明情况相反，但对许多人来说，摄入矿物质补充剂被认为是一种无风险的健康选择。已经开发出许多方法来评估与摄入金属离子相关的风险。这些方法包括直接估计安全限度，如通常基于动物实验数据得出的口服参考剂量。更复杂的方法，如目标危害商数，涉及评估长期频繁接触（如一生）的危害。后一种计算方法还便于综合考虑多种金属的影响。在许多情况下，缺乏严格的数据，因此，在将风险与人类联系起来时采用了很大的不确定性因素。由于金属毒性的性质，与胃肠道和肝脏相关的数据通常来自金属稳态疾病或大量金属过载事件。虽然这些研究为金属诱导毒性的机制提供了证据，如增强氧化应激，但将这些结果外推至健康个体或患有慢性炎症性疾病的患者并非易事。总之，金属的多样性及其对人体组织的影响，以及对其全面影响的研究匮乏，使得有必要对金属与衰老、慢性炎症性疾病和癌症之间的关联进行进一步深入研究。
