March 22, 2010 -- As few as one in five formula-fed babies and one in 20 breastfed babies are getting as much vitamin D in their diets as the nation's leading pediatricians' group now calls for, the CDC says.
In 2008, the American Academy of Pediatrics doubled its recommended daily intake of the vitamin for infants and children from 200 to 400 international units (IU) a day.
But according to the CDC estimate, only 5% to 13% of breastfed infants and 20% to 37% of formula-fed babies are getting enough vitamin D to meet the new guidelines.
CDC researchers analyzed data from a nationwide survey of infant feeding practices conducted between 2005 and 2007 to estimate how many babies were getting enough vitamin D in their diets during their first year of life.
The investigation found vitamin D supplementation to be quite low, even among exclusively breastfed babies.
Because breast milk contains very low levels of vitamin D, supplementation is recommended.
Babies who drink 34 ounces (1 liter) a day of formula get enough of the vitamin to meet the new recommendations. But only a third of the babies in the survey drank this much formula, says the CDC��s Cria G. Perrine, PhD, who led the study team.
“Breastfed infants definitely need a vitamin D supplement, and most formula-fed infants probably need supplementation too to get 400 IU a day,” she tells WebMD.
Sources of Vitamin D
Food sources of vitamin D include fatty fish, eggs, and milk. But even adults have a hard time getting the recommended levels of the vitamin through food alone.
The body also makes its own vitamin D when exposed to ultraviolet B (UBV) rays from the sun.
But the American Academy of Pediatrics recommends that children under the age of 6 months avoid sun exposure and wear protective clothing and sunscreen when in the sun to avoid burning.
While some have questioned these guidelines, Perrine says they are not likely to change because of concerns about the dangers of early-life sun exposure.
Vitamin D has long been associated with bone health, but a growing body of research has found it to be protective against many diseases common in adults, including heart disease and certain cancers.
According to the CDC research, exclusively breastfed babies got the least vitamin D in their diets, followed by babies who drank both breast milk and formula. Babies who were exclusively formula-fed got the most vitamin D.
Study: Many New Moms, Babies Deficient
The American Academy of Pediatrics recommends vitamin D supplementation of 400 IU for all breastfed babies and those who are drinking less than 1 liter a day of formula.
But pediatrician Frank R. Greer, MD, who headed the committee that came up with the new guidelines, says pediatricians are not selling the message to new parents.
“I am frankly surprised that more pediatricians are not recommending supplementation, especially to new moms who are breastfeeding,” he says.
The CDC study appears in the April issue of Pediatrics, along with another study, which finds a high rate of vitamin D deficiency among new mothers and their babies living in Boston.
Overall, more than half of the infants and more than a third of the mothers were considered vitamin D deficient. More than a third of the infants (38%) and a fifth of the mothers (23%) were considered severely deficient.
Study researcher Anne Merewood, MPH, says she was most surprised by the high rate of deficiency among the moms.
“Many of these women were taking prenatal vitamins, but this did not ensure that they had adequate vitamin D levels,” she says.
Merewood points out that supplementation may be especially important for darker-skinned people who absorb less light from the sun and for lighter skinned people who have little exposure to the sun.