Zimmermann Michael B, Köhrle Josef
Laboratory for Human Nutrition, Swiss Federal Institute of Technology, Zürich, Switzerland.
Thyroid. 2002 Oct;12(10):867-78. doi: 10.1089/105072502761016494.
Several minerals and trace elements are essential for normal thyroid hormone metabolism, e.g., iodine, iron, selenium, and zinc. Coexisting deficiencies of these elements can impair thyroid function. Iron deficiency impairs thyroid hormone synthesis by reducing activity of heme-dependent thyroid peroxidase. Iron-deficiency anemia blunts and iron supplementation improves the efficacy of iodine supplementation. Combined selenium and iodine deficiency leads to myxedematous cretinism. The normal thyroid gland retains high selenium concentrations even under conditions of inadequate selenium supply and expresses many of the known selenocysteine-containing proteins. Among these selenoproteins are the glutathione peroxidase, deiodinase, and thioredoxine reductase families of enzymes. Adequate selenium nutrition supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage by excessive iodide exposure. In regions of combined severe iodine and selenium deficiency, normalization of iodine supply is mandatory before initiation of selenium supplementation in order to prevent hypothyroidism. Selenium deficiency and disturbed thyroid hormone economy may develop under conditions of special dietary regimens such as long-term total parenteral nutrition, phenylketonuria diet, cystic fibrosis, or may be the result of imbalanced nutrition in children, elderly people, or sick patients.
几种矿物质和微量元素对正常甲状腺激素代谢至关重要，例如碘、铁、硒和锌。这些元素同时缺乏会损害甲状腺功能。缺铁会通过降低血红素依赖性甲状腺过氧化物酶的活性来损害甲状腺激素合成。缺铁性贫血会削弱碘补充剂的效果，而补充铁则可改善碘补充剂的疗效。硒和碘联合缺乏会导致黏液水肿性克汀病。即使在硒供应不足的情况下，正常甲状腺仍保持高浓度的硒，并表达许多已知的含硒半胱氨酸的蛋白质。这些硒蛋白包括谷胱甘肽过氧化物酶、脱碘酶和硫氧还蛋白还原酶家族的酶。充足的硒营养有助于高效合成和代谢甲状腺激素，并保护甲状腺免受过量碘暴露的损害。在碘和硒严重联合缺乏的地区，在开始补充硒之前必须先使碘供应正常化，以预防甲状腺功能减退。在长期全胃肠外营养、苯丙酮尿症饮食、囊性纤维化等特殊饮食方案的情况下，可能会出现硒缺乏和甲状腺激素代谢紊乱，或者这可能是儿童、老年人或患病患者营养不均衡的结果。
