Iron, copper and zinc status in rats fed on diets containing various concentrations of tin

The effects of various dietary concentrations of Sn (1, 10, 50, 100 and 200 mg/kg; added as SnCl2) on Fe, Cu and Zn status of rats were determined. After feeding the diets for 28 d body weight was not significantly affected, but there was a linear inverse response of feed intake. Plasma, kidney, spleen and tibia Fe concentrations as well as blood haemoglobin concentration and percentage transferrin saturation decreased in a linear dose-response manner as the level of dietary Sn increased. The addition of Sn to the diet depressed Cu status, as indicated by a significant inverse response of plasma, liver, kidney, spleen and tibia Cu levels. Plasma, kidney and tibia Zn concentrations were decreased by increasing levels of dietary Sn, but spleen and liver Zn concentrations were not significantly influenced. Fe, Cu and Zn status was influenced by dietary Sn concentrations lower than 50 mg/kg. If the results can be extrapolated to man it would follow that a high v. low Sn concentration in the human diet, which can be as distinct as 75 v. 2 mg/kg dry diet, may decrease plasma and tissue concentrations of Fe, Cu and Zn by up to 15%.