Lack of an effect of dietary fructose on severity of zinc deficiency in rats.

Because feeding rats diets containing fructose as the carbohydrate source reduces copper and selenium status, we investigated whether the type of dietary carbohydrate also affected indices of zinc status. The experimental design was a 2 X 2 factorial study with the source of dietary carbohydrate (cornstarch or fructose) and the level of dietary zinc (0.7 or 31 micrograms Zn/g) as the variables. The experiment utilized 76 weanling male Sprague-Dawley rats randomly assigned to one of four dietary groups. Animals fed a zinc-deficient fructose diet were allowed to consume the diet ad libitum; all other groups were pair-fed to that group to ensure equivalent nutrient and energy intake. The results of the 29-d study showed that the most sensitive indices of zinc status measured, including growth, survival and the zinc concentrations of plasma, femur and testes, were not affected by the type of dietary carbohydrate. This lack of an effect of fructose on the zinc status of the experimental animals indicates that the ability of fructose to exacerbate copper and selenium deficiencies is specific, rather than representing a generalized effect of this simple sugar on the requirements and/or metabolism of all essential trace elements.