A stable isotope study of copper absorption in young men: effect of phytate and alpha-cellulose

A sixty-three day study was conducted with young men confined to a metabolic unit to study the effects of alpha-cellulose and phytate on copper absorption. Copper absorption was determined with 65Cu, a stable isotope of copper, during each of 3 dietary treatments (basal diet, basal diet + alpha-cellulose, or basal diet + phytate). The addition of alpha-cellulose or phytate to the basal diet did not affect copper absorption. Average copper absorption was 35.0% from the basal diet, 34.1% from the diet with 0.5 g alpha-cellulose per kg body weight added, and 31.4% from the diet with 2.34 g of phytate as sodium phytate added to the diet. Copper absorption was significantly different between subjects and averaged 44.1%, 26.8%, 33.4%, and 29.5% in individual subjects. The results suggest that high levels of either alpha-cellulose or phytate do not have marked effects on copper absorption, but copper absorption differs between individuals.