Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2001
Publication Date: 9/1/2002
Citation: Olivares,M., Lonnerdal,B., Abrams,S.A.; Pizarro,F., Uauy,R. 2002. Age and copper intake do not effect copper absorption, measured with the use of 65Cu as a tracer, in young infants. 76(3):641-645.
Interpretive Summary: The fetus receives a considerable amount of copper from the mother, and it is thought that the liver copper stores that the fetus has accumulated may help prevent copper deficiency during the early months of the infant's life. After birth, liver copper decreases in the infant, while blood levels increase and become more similar to an adult's. We wanted to find out whether newborns and small infants can efficiently make the absorption and biliary excretion adaptations that are necessary to properly regulate copper homeostasis. Essentially, the point of this study was to evaluate the effects of age and copper intake on copper absorption in infants during the first 3 months of life. We studied nearly 40 infants from 1 to 3 months of age, with a birth weight above 2500 grams. Half of them were given a harmless isotope tracer-marked copper supplement in their baby bottles at home over 15 days. Afterwards, we measured the babies' copper absorption by ymeasuring the tracer-marked material in the feces that had been collected. Our results showed that copper absorption is very high in young infants, and copper absorption is not downregulated within or slightly above the range of acceptable copper intake. Further studies are needed to find out how well controlled copper absorption is at higher copper intakes during the first months of life.
Technical Abstract: Copper homeostasis involves a high degree of regulation in which changes in absorption and biliary excretion are the main mechanisms. Whether neonates and small infants can make these changes efficiently is unknown. We evaluated the effect of age and copper intake on copper absorption in infants during the first 3 mo of life. Thirty-nine healthy infants (19 infants aged 1 mo and 20 infants aged 3 mo) were selected. One-half of the subjects were randomly assigned to receive oral supplementation of 80 mg Cu (as copper sulfate). kg body wt(-1). d(-1) for 15 d. At the end of the trial, copper absorption was measured by using orally administered (65)Cu as a tracer and fecal monitoring of recovered (65)Cu. Mean (+/- SD) copper absorption at 1 mo of age was 83.6 +/- 5.8% and 74.8 +/- 9.1% for the unsupplemented and supplemented infants, respectively. The corresponding figures at 3 mo of age were 77.6 +/- 15.2% and 77.7 +/- 11.3%. A two-way analysis of variance showed that age, copper supplementation, and the interaction between age and copper supplementation did not have a significant effect on copper absorption. There was an inverse correlation between total fecal copper and the percentage of (65)Cu absorption (r = -0.50, P < 0.003). Copper absorption in young infants is high but does not respond to copper intake within the range tested.