Exclusive breastfeeding increases child's risk for vitamin D deficiency; black, darker-skinned children already have increased risk

Exclusive breastfeeding can increase a child's risk of developing rickets because breast milk alone does not provide adequate levels of vitamin D, a critical ingredient that helps to absorb calcium and build strong bones, the New York Times reports. Rickets develops when a child's vitamin D levels are too low and is characterized by the curving of a child's legs and the softening of other bones. Some children are asymptomatic.

Darker-skinned children have a greater risk of vitamin D deficiency than other children because they do not absorb vitamin D as easily through the skin. Sunlight enables the skin to synthesize vitamin D.

Cases of nutritional rickets among infants and young children in the U.S. have been "accumulating over the last decade or so," and children with the condition are more likely to be black or dark-skinned and have been breastfed exclusively for an extended period of time without vitamin supplementation, according to the Times. Some experts say that an increase in infants being exclusively breastfed, more children drinking soda or juice and less milk, and children spending less time in the sun could contribute to rickets re-emerging as a public health problem, the Times reports.

According to the Times, while physicians have known for years that exclusive breastfeeding is associated with vitamin D deficiency in infants and rickets, many are "reluctant to say anything that might discourage breastfeeding." The American Academy of Pediatrics in 2003 recommended that infants who are exclusively breastfed receive vitamin D drops daily.

According to one study on rickets and vitamin D that included mostly black and Hispanic infants and toddlers, 40% of the participants had low levels of vitamin D, 12% were vitamin D deficient, 13 children showed evidence of bone loss and three children had signs of rickets. The study, published in the June issue Archives of Pediatrics & Adolescent Medicine, also found that breastfeeding without vitamin supplementation was a significant risk factor for rickets.

Study author Catherine Gordon, director of Children's Hospital Boston's bone health program, said, "I completely support breastfeeding, and I think breast milk is the perfect food, and the healthiest way to nourish an infant. However, we're finding so many mothers are vitamin D deficient themselves that the milk is therefore deficient, so many babies can't keep their levels up." She added, "They may start their lives vitamin D deficient, and then all they're getting is vitamin D deficient breast milk" (Rabin, New York Times, 8/26).