O'Neil-Cutting M A, Bomford A, Munro H N
J Nutr. 1981 Nov;111(11):1969-79. doi: 10.1093/jn/111.11.1969.
Earlier investigators observed that addition of large amounts of zinc to the diet or rats can retard growth, lower their hemoglobin levels and reduce storage of iron. In the present studies, addition of 0.75% zinc to a synthetic diet confirmed the reduced storage of iron in the livers and spleens of growing rats, but failed to show an effect on growth rate or hemoglobin levels. The adverse effects of zinc excess on growth and hemoglobin level could, however be reproduced by replacing the Rogers-Harper salt mixture used in the present studies with the Wesson salt mixture use in the earlier studies. Rats fed excess zinc along with the Wesson salt mixture grew less well, had anemia and also had low level in copper in their livers. It is suggested that addition of zinc to the low copper Wesson salt mixture reduced copper absorption sufficiently it deplete liver copper to a level at which mobilization of liver iron stores by a copper-dependent mechanism became impaired, thus depriving red cell production and tissue enzymes of stored iron. The mechanism by which iron stores are depleted by addition of zinc to the better balanced Rogers-Harper salt mixture remains unexplained It is not due to interference by zinc with iron adsorption from the diet nor with cellular uptake of iron from circulating transferrin, and the capacity of tissues to store iron as ferritin is not impaired.
早期的研究人员观察到，在大鼠的饮食中添加大量锌会阻碍其生长，降低血红蛋白水平并减少铁的储存。在目前的研究中，在合成饮食中添加0.75%的锌证实了生长中大鼠肝脏和脾脏中铁储存的减少，但未显示对生长速率或血红蛋白水平有影响。然而，用早期研究中使用的韦森盐混合物替代本研究中使用的罗杰斯 - 哈珀盐混合物，可以重现锌过量对生长和血红蛋白水平的不利影响。与韦森盐混合物一起喂食过量锌的大鼠生长较差，患有贫血，并且肝脏中的铜含量也较低。有人认为，在低铜的韦森盐混合物中添加锌会充分降低铜的吸收，从而将肝脏铜消耗到一定水平，此时依赖铜的机制对肝脏铁储存的动员受到损害，从而使红细胞生成和组织酶无法获得储存的铁。在平衡更好的罗杰斯 - 哈珀盐混合物中添加锌导致铁储存耗尽的机制仍未得到解释。这不是由于锌干扰饮食中铁的吸收，也不是由于锌干扰细胞从循环转铁蛋白中摄取铁，并且组织将铁储存为铁蛋白的能力也未受损。
