It's also hard for your baby to digest the protein and fat in cow's milk.
To provide the best diet and nutrition for your infant, the AAP recommends that:
If possible, you should feed your baby breast milk for the first 6 months of life.
You should give your baby only breast milk or iron-fortified formula during the first 12 months of life, not cow's milk.
Starting at age 6 months, you may add solid foods to your baby's diet.
If breastfeeding is not possible, infant formulas provide a healthy diet for your infant
Whether you use breast milk or formula, your baby may have colic and be fussy. These are common problems in all babies. Most of the time, cow's milk formulas don't cause these symptoms, so it won't help if you switch to a different formula.
American Academy of Pediatrics Policy Statement: Breastfeeding and the Use of Human Milk. Pediatrics. March 1, 2012;12(3):e827-e841.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.