A histidine supplement and regulation of the zinc status in Swiss random mice.

The effects of histidine on the zinc status are controversial. In mice, we studied the effects of a moderate histidine supplement on the regulation of the zinc status using subcutaneously administered 65Zn. In animals fed a zinc-adequate diet, histidine supplement did not cause changes in the zinc status (zinc concentrations, 65Zn tissue distribution, and tissue specific activities). Neither effects on the regulation of the zinc status (65Zn retention, excretion and biological half-life) could be demonstrated. However, the combination of a low zinc diet and moderate histidine supplementation caused changes in the regulation of the zinc status (lower 65Zn retention, associated with increased fecal excretion and a shorter biological half-life), aggravating the dietary deficiency (lower bone zinc, a shift in the 65Zn tissue distribution). Reviewing the literature, it seems that only a molar histidine/zinc ration of 2,000 or higher will cause zinc deficiency.