Betaine and homocysteine concentrations in infant formulae and breast milk

Background: Early diagnosis and treatment of homocystinuria with methionine-free or low methionine formulae significantly improve prognosis in children found by newborn screening and treated soon after birth. Betaine (Bet) supplementation is also an effective strategy for dietary treatment of homocystinuria. However, previous reports on diet therapy have only examined methionine and cysteine concentrations but not those of Bet and homocysteine (Hcy) in infant diets. Methods: We measured Bet and Hcy concentrations in three methionine-free formulae. five infant starter formulae, and 33 samples of human breast milk from 10 mothers. Results: In methionine-free formulae, Hey but not Bet was isolated. However, in human breast milk and infant starter formulae, both Bet and Hcy were detected. However. the Bet concentration was not sufficient for the treatment. Conclusions: Our study suggests that methionine-free formulae should have Hcy, eliminated and be fortified with Bet to the concentration of 150 mg/dL for the treatment of homocystinuria.