And if sugar levels stay high, the sugars' free ends can attach to other proteins or other sites on the same protein, called advanced glycation. These cross links bend proteins out of shape, rendering them useless. Researchers found that both the early and advanced stages of protein glycation increased significantly in rats fed a copper-deficient diet. One sensitive indicator of advanced glycation was at least sixfold higher in the copper-deficient rats. It was nearly undetectable in the control rats.
Human diets contain more copper than the rat diets.
But the average copper content of U.S. diets falls below the suggested daily range of 1.5 to 3.0 mg. The researchers speculate that years of eating a diet low in the mineral may, by increasing glycation, contribute to age-related decline in tissue function. In a recent study of 135 premature infants, lactase activity was a strong indicator of intestinal maturity, which affects an infant's ability to handle feedings. Premature infants can't be released from the hospital until they are on full human milk or formula feedings. As a rule, they are started on intravenous feedings at birth.