Lactose absorption from breast milk and humanized cows' milk formula

It has been suggested that lactose is better absorbed from cows' milk than from breast milk. One possible cause for this difference is that the higher phosphate content of cows' milk causes lactose mutarotation, facilitating absorption. We studied lactose absorption from breast milk and from a humanized, low phosphate formula in twenty-six breast fed infants, ranging in age from one to three months. A hydrogen breath test was performed after a breast milk meal and repeated two days later after formula feeding. No difference was found in lactose absorption from the two types of milk. Intestinal transit time was also similar, and the design of the study precluded changes in colonic flora between the two tests in each infant. The lower phosphate content of the formula, compared with that of regular cows' milk (296 vs 950 mg/L, respectively), may partially explain the difference between our results and previously published data.