Oct. 30, 2000 (Chicago) -- Because parents are actually following the advice of pediatricians, many children are not getting enough vitamin D. Thus, pediatricians are seeing increasing numbers of infants and small children with a bone disease called rickets. A presentation on the issue was given here at a meeting of the American Academy of Pediatrics (AAP).
There are two reasons for the resurgence of rickets, says Susan Baker, MD, PhD, chair of the AAP nutrition committee, and both are a testament to the success of public health campaigns: one to avoid sun exposure and the other to increase breastfeeding.
The concern about vitamin D and risk of rickets is so serious that next spring the CDC will convene an expert panel to "develop a recommendation for vitamin D supplementation for all breastfed infants," says CDC epidemiologist Kelley Scanlon, PhD.
Meanwhile, U.S. Surgeon General David Satcher announced Monday a campaign to get more mothers -- especially black mothers -- to breastfeed. The risk for rickets is particularly high for black children and other dark skinned children because dark pigmentation is a natural filter for the sun.
Rickets is caused by a lack of vitamin D. It weakens the bones in small children, resulting in bowed legs, soft skulls, and delays in crawling and walking. Because of nutritional advances in the U.S., "most doctors believed that rickets had pretty much disappeared," Baker says. But they are wrong.
Baker explains that the sun helps to produce vitamin D through the skin. But parents finally have gotten the message that sun exposure can lead to skin cancer. They have been slathering their children with sun block or keeping them covered with protective gear, therefore, "children are no longer getting sufficient sun exposure to [create] vitamin D this way," Baker says.
The second way that humans get vitamin D is through their diets. "Mother's milk is best for infants, but it is not a perfect food," she says. "It is actually a very poor source of vitamin D ... and to increase the vitamin D level in human milk even slightly, the mother would have to be given a toxic level of vitamin D," says Baker, who is a professor of pediatrics at State University of New York at Buffalo.
Better dietary sources of vitamin D include liver, fatty fish, liver oils, and "yolks of eggs from hens given vitamin D supplementation," she says. But the best dietary source is fortified food, especially milk, Baker says. "Milk contains 100 IUs of vitamin D in every 8 ounce serving," she says. But the federal government requires that infant formula be fully fortified to contain the complete recommended daily allowance for vitamin D, which is 400 IUs per day.
Scanlon recently co-authored a CDC study that reported on six cases of rickets in Georgia in the late '90s. "Six cases seems very minimal, but these are hospitalized cases, and we suspect that the number of nonhospitalized cases, or the true rate of rickets, is much higher," Scanlon tells WebMD.
Scanlon says that another study, conducted in North Carolina, reported on 30 cases over a 10-year period, "with 18 cases diagnosed in the last 18 months," she says. In both Georgia and North Carolina, all cases were among black children.
Mothers are told to give children 400 IUs of vitamin D a day. But even this approach is not easy because "currently, there is no simple vitamin D supplement available," Baker says. Instead, parents are given prescriptions for a children's multivitamin called Tri-Vi-Flor.
Scanlon says that because infant formula is fully fortified, health officials in "North Carolina tell mothers to stop vitamin D supplementation if the infant is taking even a single supplemental bottle [of formula]." She says, too, that the risk of vitamin D toxicity is reduced by "careful instructions to mothers to limit the supplement to just 400 IUs." Too much vitamin D can cause nausea and vomiting, weight loss, and kidney problems.
Although the new CDC guideline will be limited to breastfed infants, Baker says pediatricians also should consider vitamin D supplements for "toddlers, especially toddlers whose parents decide that they are lactose intolerant or have some other aversion to milk. For children who are drinking this junk, vitamin D supplementation is absolutely necessary." Baker tells WebMD that she includes in her definition of junk, "Kool-Aid, Gatorade, rice milk, and soy milk." She says, however, that "there are milk substitutes that are fortified, and if parents insist on no milk, then I tell them to go to the grocery store -- not the health food store -- and find the fortified products."