Intestinal absorption of copper from drinking water containing fulvic acids and an infant formula mixture studied in a suckling rat model

The purpose of this study was to investigate if the intestinal absorption o f copper in drinking water is altered in the presence of complexing agents from a fulvic acid mixture and an infant formula powder. Ten to twelve day old rat pups were given a single oral dose of radio-labeled Cu in deionized water (0.93 mg Cu/l), in water containing fulvic acids (10 mg/l), in infan t formula mixed with deionized water, or in infant formula mixed with water containing fulvic acids. Six hours after dosage, radioactive Cu was analyz ed in the mucosa of the small intestine, the liver and the remaining carcas s (excluding the liver and gastrointestinal tract) by gamma counting. Dialy sis and centrifugation experiments showed that Cu was complexed by componen ts in the fulvic acid and formula mixtures, although the presence of fulvic acids in the water did not alter the Cu fractionation in the formula. The fractional Cu uptake (% of dose) from the intestinal lumen to the mucosa wa s not markedly changed by the presence of the chelating agents. However, th e retention of Cu in the intestinal mucosa was increased by both fulvic aci ds and formula. Concomitantly, the absorption rate of Cd to the circulatory system was decreased. No interactive effect between fulvic acids and formu la was found on the Cu absorption. These findings indicate that the water q uality may be an important determinant of the rate of intestinal Cu absorpt ion from drinking water. Moreover, in the future risk assessment of copper in drinking water, the possibility of alterations in absorption of drinking -water Cu has to be considered when the drinking water is used for cooking.