UC Berkeley

The effects of low zinc, high fructose diet on growth and adipocyte metabolism were examined in rats. At 28 days of age, animals were assigned to diets either adequate in zinc (30 ppm) with water (AZW) or fructose solution (AZF), or low in zinc (5 ppm) with water (LZW) or fructose solution (LZF). Body weight and food and fructose solution intake were measured three times a week. Blood samples were collected at baseline, 4 weeks, and 8 weeks, and energy expenditure was measured. The rats were killed at 12 weeks. Adipocytes were cultured in medium containing C14-glucose and physiological insulin concentrations. The animals in the LZF group consumed less energy and gained less weight than the other groups. Serum zinc concentrations were lower in the LZF than the AZF group. Energy expenditure over a 24-h period did not differ between groups; however, the respiratory quotient in the fed state was higher in the groups consuming fructose solution than in those consuming water. The mesenteric adipocytes from the animals in the LZF group utilized more glucose. Thus, the addition of fructose to a LZ diet reduced energy intake and growth and altered adipocyte fuel metabolism in young growing rats.