Soy or milk-based formula: Which is better for my baby?
Expert Answers
Jill Stovsky, exercise physiologist and dietician
Soy formula has no nutritional advantage over milk-based formula and vice versa. Both are fortified with the same vitamins and minerals.
Usually parents choose soy formula when their baby is sensitive or allergic (or potentially so) to cows' milk protein, or when a baby is having trouble digesting lactose or milk sugar. Babies can be chronically sensitive to cows' milk protein and may have to avoid it for the first several months of life. If your baby cries or is irritable during feedings or immediately afterward, or if he has diarrhea, he may be allergic to his formula. Check with your baby's doctor if you think he's having problems digesting the milk; the doctor may recommend switching to soy milk.
That said, remember that soy protein is just as likely to cause food allergies. In fact, most babies who are allergic to cows' milk protein are also allergic to soy protein. If this happens, your child's healthcare provider may ask you to try other brands of formula that don't contain cows' milk protein. Sometimes, you might need to change brands a few times to find what's best for your baby.