COPPER ABSORPTION AND BIOAVAILABILITY

The human gastrointestinal system can absorb 30-40% of ingested copper from the typical diets consumed in industrialized countries. Experime ntal data support the existence of a carrier-mediated transport mechan ism with an affinity constant in the micromolar range. Aging probably decreases the efficiency of copper homeostasis, resulting in higher pl asma copper concentrations in the elderly. Physiologic differences may account for the higher cupremia of females. Supplements of minerals w ith similar chemical characteristics could reduce copper absorption. T his property has pharmacologic applications in Wilson disease. Manipul ation of the fiber content of the diet may have an indirect effect on copper bioavailability by altering the bioavailability of mineral anta gonists, Proteins and soluble carbohydrates tend to improve copper abs orption and bioavailability by enhancing its solubility and intestinal bulk flow. Organic acids, other than ascorbic acid, or agents that fo rm low-molecular-weight chelates, are likely to have a positive effect on overall copper absorption. Conditions associated with malabsorptio n of macronutrients and gastrointestinal disease can impair copper upt ake and contribute to suboptimal copper status.