Vitamin D plays a vital role in bone health. In severe cases of vitamin D deficiency in infants and children, rickets, defined as ineffective bone mineralization, may occur and lead to weak bones.

Vitamin D is made in the skin after exposure to sunlight or absorbed in the gut from one’s diet. However, since parents are advised to avoid exposing infants to direct sunlight, babies receive most of their vitamin D through their diets. Current guidelines released by the American Academy of Pediatrics (AAP) in 2008 recommend a minimum daily intake of 400 international units (IU) of vitamin D for all infants and children. As breast milk and formula contain different amounts of vitamin D, what does this mean for babies who are breastfed, as well as those who are formula-fed?

Breastfeeding is the preferred form of infant feeding, and the AAP recommends exclusive breastfeeding for at least six months. Vitamin D supplementation is indicated in babies who are exclusively taking breast milk, because they do not receive adequate vitamin D through breast milk alone. However, the study “Adherence to Vitamin D Recommendations Among US Infants,” published in the journal Pediatrics in April 2010, elucidated that most infants, not only those who are exclusively breastfed, require vitamin D supplementation to achieve the recommended 400 IU per day.

Standard infant formulas contain at least 400 IU of vitamin D per liter. However, unless an infant is taking at least 1 liter of formula per day, formula alone would not provide sufficient vitamin D. Conveniently, vitamin D supplements for infants are available as a liquid solution, providing the recommended dose of 400 IU in one milliliter or less.

Supplementation in exclusively or primarily breastfed infants should continue until the child is taking at least 1 liter of whole milk per day, which should not be introduced into the infant’s diet until 12 months of age. Supplementation in formula-fed infants should continue until the child is taking at least 1 liter of either formula or whole milk per day, whichever comes first.

Dr. Vivek is a junior faculty member in General Pediatrics at Cohen Children’s Medical Center.