Although breastfeeding is the recommended method for feeding infants and breast milk provides most of the nutrients an infant needs, it does not provide infants with adequate vitamin D. Vitamin D is required to prevent rickets, a type of vitamin D deficiency. This disease is rare among breastfed infants but can occur if vitamin supplementation or exposure to sunlight is inadequate. (Exposure to sunlight helps the body to make vitamin D in place of supplementation.)1
The current American Academy of Pediatrics (AAP)–recommended daily vitamin D intake is 400 IU per day for all infants and children beginning from the first few days after birth.2 Human breast milk contains a vitamin D concentration of 25 IU per liter (about 4 cups) or less. Therefore, to meet the 400 IU daily requirement, supplementation is required.
If an infant is weaned to a vitamin D-fortified infant formula and consumes at least 4 cups per day, then additional supplementation with vitamin D is not necessary.1
Breastfeeding is supplemented by feeding an infant expressed breast milk from a bottle, formula, or breast milk from another mother. Such supplementation may be needed in the following situations:3
In the Mother:
Breast surgery or other trauma
Primary breast insufficiency that prevents adequate milk production
Physical separation from the infant
In the Infant:
Weight gain insufficient to maintain health (also sometimes called failure to thrive)
Cleft lip and/or palate or other abnormality that prevents normal suckling ability
Jaundice or liver problems
Serious illness or prematurity that requires the infant to be cared for in a special nursery
Many of these conditions require a health care provider's care. You should always talk with your child's health care provider about whether to supplement your breastfeeding.
To keep supplementation from shortening or otherwise interfering with breastfeeding, you should supplement only after your infant is breastfeeding effectively and thriving on your breast milk.3
Mixing formula with breast milk in the same container is one way of supplementing breast milk. You may want to supplement your breast milk with infant formula if your milk supply is low or when you are physically separated from your infant.3
Supplementing your breast milk with formula, however, may not be nutritionally the same as giving breast milk.4 Discuss the practice with your infant's health care provider before starting to mix formula with your breast milk.
The term "complementary feeding" refers to giving your baby solid and liquid foods other than breast milk or infant formula. As babies grow, they have nutritional needs that breast milk or infant formula alone cannot meet. Complementary feeding helps meet those nutritional needs. It is also important for infants' jaw and muscle development and helps them develop speech later.5
The AAP and the World Health Organization (WHO) recommend introducing safe, nutritious complementary foods into your infant's diet around 6 months of age.4,6 The exact timing depends on the infant's developmental readiness, meaning whether the baby can open his or her mouth and lean forward when interested in food. Studies show that introducing complementary foods before 4 months offers little health benefit to the infant and can increase the risk of food allergies and choking.5
Some complementary foods are often called "baby foods" and can be pureed or mashed-up versions of meats, fruits, and vegetables. Different foods offer different nutrients. For example, around 4 to 6 months of age, babies' iron and zinc needs are higher than what breast milk or infant formula alone can provide. Complementary feeding of fortified cereals or pureed meats can provide these nutrients.
If you have any questions about complementary feeding, or if your family has a history of food allergies, talk to your infant's health care provider.
Wagner, C. L., Greer, F. R., & American Academy of Pediatrics Section on Breastfeeding and Committee on Nutrition. (2008). Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics, 122(5), 1142–1152. Retrieved November 4, 2016, from http://pediatrics.aappublications.org/content/122/5/1142