Effects of changes in dietary energy density and the amount of fructose on indices of copper status and metabolic parameters in male rats

Abstract

This study was conducted to test the effects of changes in dietary energy density and fructose content on the signs of copper deficiency in rats. For 7 weeks male weanling rats were fed ad libitum diets prepared with adequate (95 μmol Cu/kg of diet) or low (9.5 μmol Cu/kg of diet) copper levels that were of different energy density and fructose levels. Rats fed the copper-deficient diet with a higher energy density and a high fructose level showed the characteristic abnormalities of copper deficiency. These include reduced body weight; enlarged heart, liver, and testes; atrophy of the pancreas; a low hepatic copper level; a low hemoglobin level; anemia; reduced red blood cell and hepatic superoxide dismutase activity; elevated serum cholesterol, triacylglycerol, glucose, and blood urea nitrogen levels; elevated hepatic iron; and mortality. Lowering the energy density and/or reducing the fructose level improved many of the signs associated with copper deficiency and prevented mortality. Reducing the energy density of the diet and the fructose level produced a marked improvement in the activity of the copper-dependent antioxidative enzyme, superoxide dismutase, in liver and red blood cells. It is possible that this improvement in copper-dependent antioxidative enzyme activity is partly responsible for the improvement in the signs of copper deficiency.