Blood zinc, copper, insulin and glucose levels in carbohydrate-sensitive and normal men given a sucrose or invert sugar tolerance test

Twelve carbohydrate-sensitive and 12 non-carbohydrate sensitive (normal) men were studied. Carbohydrate sensitivity was identified by hyperinsulinemic and normoglycemic responses to a sucrose load. In a blocked split-plot design, fasted subjects were given 2 g/kg body weight of sucrose or invert sugar, and responses of plasma zinc, copper, insulin, and glucose were determined. Erythrocyte zinc and copper also were measured. Blood samples were taken 0, 0.5, 1, 2, and 3 hours after the sugar loads were given. Plasma zinc, copper, insulin, and glucose did not differ significantly between the two sugar loads. Neither did erythrocyte zinc and copper differ significantly between the two load doses. Also, plasma zinc, copper, and glucose, as well as erythrocyte zinc and copper, did not differ significantly between the carbohydrate-sensitive and normal men. Plasma insulin was significantly higher in the carbohydrate-sensitive than the normal men. Plasma zinc did not change significantly between sampling times. Plasma copper declined progressively over the testing period. The greater the elevation of plasma glucose above the fasting level, the greater the plasma copper was depressed. Copper appears to be withdrawn from plasma after sugar loading to facilitate glucose uptake and metabolism.