The American Academy of Pediatrics (AAP) recommends breastfeeding infants until 12 months of age. However, not all mothers are physically able to breastfeed or choose to breastfeed their infant. In these cases, parents need to rely on another source of nutrition such as infant formula or whole milk. With many nutritional differences, whole milk and infant formula are far from equivalent. Due to these nutritional differences and high allergy risk, the AAP Committee on Nutrition strongly advises against using any form of cow's milk, including whole milk, for infants under 12 months old.
Infant Formula Development
Infant formulas are designed to mimic breast milk’s nutrition as closely as possible. Formulas provide the majority of the same nutrients in the same amounts compared to breast milk. The main difference between breast milk and infant formula is the lack of live antibodies in infant formulas. The formula development process assures not only vitamin and minerals levels are infant appropriate but also the amount and types of fat, protein and sugars. The U.S. Food and Drug Administration’s Infant Formula Act provides strict standards that all formulas meet the same nutritional guidelines.
When born, infants do not have a fully developed digestive system and may have problems digesting the proteins found in whole milk. Breast milk and infant formula have a high concentration of whey protein and a low concentration of casein protein. On the other hand, whole milk is 18 percent whey and 82 percent casein. Casein protein is large and more difficult to digest. The large protein molecules can irritate the intestines and cause intestinal bleeding. The amount of protein in whole milk compared to breast milk and infant formula is also very different. Per 100 grams, breast milk contains 1 gram, infant formula contains 2 grams, and whole milk contains 3.3 grams of protein. The large amount of protein found in whole milk can damage the infant's developing kidneys. By enhancing digestibility and reducing the protein amount, infant formula protein is similar to breast milk protein.
Due to the large amount of calcium in whole milk (130 milligrams per 100 grams), iron absorption is drastically reduced to approximately 4 percent. Even for infants obtaining iron from fortified cereals and other foods, the high amount of calcium in the milk will reduce the iron absorption from these plant sources. In the body, calcium and iron will bind together, decrease absorption, and cause fecal excretion. In the first year of life, lack of iron can lead to developmental problems in the brain and nervous system.
Vitamins and Minerals
Whole milk does not contain all the vitamins and minerals needed in the first year of life; it is low in vitamin E and C. The reduced levels of vitamin C can decrease immunity and increase the infant’s risk of infection. Whole milk consumption can also lead to increased intakes of sodium, potassium and chloride. Overload of these electrolytes can place unnecessary strain on the kidneys. High sodium intakes can lead to water retention and dehydration.
Essential Fatty Acids
Infants need linoleic acid and other essential fatty acids for healthy brain development. Linoleic acid is nonexistent in whole milk. In order to provide optimal levels of essential fatty acids and improved digestibility, infant formula contains vegetable oil.
Introduction of Whole Milk
Overall, whole milk should not be provided until one year of age. Waiting to introduce whole milk helps prevent allergic reactions that tend to develop early in life. After the infant's digestive system has fully developed, whole milk can be a great source of nutrients for a toddler. However, if your child is overweight or at risk of becoming overweight, or if you have a family history of weight problems, the AAP recommends 2% milk instead of whole milk to decrease risk of weight-associated diseases.