Whanger P D
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
Br J Nutr. 2004 Jan;91(1):11-28. doi: 10.1079/bjn20031015.
Selenomethionine (Semet) is the major seleno-compound in cereal grains and enriched yeast whereas Se-methylselenocysteine (SeMCYS) is the major seleno-compound in Se-accumulator plants and some plants of economic importance such as garlic and broccoli exposed to excess Se. Animals can metabolize both Semet and SeMCYS. Epidemiological studies have indicated an inverse relationship between Se intake and the incidence of certain cancers. Blood or plasma levels of Se are usually lower in patients with cancer than those without this disorder, but inconsistent results have been found with toenail-Se values and the incidence of cancer. There have been eight trials with human subjects conducted on the influence of Se on cancer incidence or biomarkers, and except for one, all have shown a positive benefit of Se on cancer reduction or biomarkers of this disorder. This is consistent with about 100 small-animal studies where Se has been shown to reduce the incidence of tumours in most of these trials. Se-enriched yeast is the major form of Se used in trials with human subjects. In the mammary-tumour model, SeMCYS has been shown to be the most effective seleno-compound identified so far in reduction of tumours. Several mechanisms have been proposed on the mechanism whereby Se reduces tumours. Even though SeMCYS was shown to be the most effective seleno-compound in the reduction of mammary tumours, it may not be the most effective seleno-compound for reduction of colon tumours.
硒代蛋氨酸（Semet）是谷物和富硒酵母中的主要含硒化合物，而硒甲基硒代半胱氨酸（SeMCYS）是富硒植物以及一些具有经济重要性的植物（如暴露于过量硒的大蒜和西兰花）中的主要含硒化合物。动物能够代谢Semet和SeMCYS。流行病学研究表明，硒摄入量与某些癌症的发病率呈负相关。癌症患者的血液或血浆硒水平通常低于无此疾病的患者，但关于 toenail-Se 值与癌症发病率的研究结果并不一致。已经进行了八项针对人类受试者的关于硒对癌症发病率或生物标志物影响的试验，除一项试验外，所有试验均表明硒对降低癌症或该疾病的生物标志物有积极作用。这与大约100项小动物研究一致，在大多数这些试验中，硒已被证明可降低肿瘤发病率。富硒酵母是在人类受试者试验中使用的主要硒形式。在乳腺肿瘤模型中，SeMCYS已被证明是迄今为止在减少肿瘤方面最有效的含硒化合物。已经提出了几种关于硒减少肿瘤的机制。尽管SeMCYS被证明是减少乳腺肿瘤最有效的含硒化合物，但它可能不是减少结肠肿瘤最有效的含硒化合物。
