Free and Bound Tryptophan in Human Milk during Early Lactation

Abstract
Total (protein-bound and free) and free tryptophan levels of breast milk were evaluated in 10 mothers of term infants on the 3rd, 4th, 5th, and 30th day of lactation. We found high levels of both total and free tryptophan in the colostrum. This variation in tryptophan content of breast milk may reflect the requirement of the human neonate.