Doctors double vitamin D for children

By Leigh Hopper Oberholzer, Globe Correspondent  |  October 13, 2008

The best-known example of vitamin D deficiency is rickets, a bone-softening disease that can result in bowed legs and fractures, but a burgeoning body of evidence links vitamin D deficiency with an array of serious ailments. New research shows it plays a role in certain cancers, autoimmune diseases, and even diabetes.

That's why today the American Academy of Pediatrics is set to announce it is doubling the amount of vitamin D it recommends for infants, children, and adolescents to 400 IU a day, beginning in the first few days of life.

"I don't know of another vitamin that has effects on multiple tissues like vitamin D," said vitamin D researcher Dr. Catherine Gordon, director of the bone health program at Children's Hospital Boston. "As pediatricians, we're still doing research on health outcomes, (and) the relation between vitamin D deficiency during childhood or adolescence and outcomes later in life like osteoporosis, cancer risk, and risk of developing multiple sclerosis. But there are compelling data in adults suggesting an association."

That growing awareness - along with the historical precedence of safely giving 400 IU per day to children - prompted the American Academy of Pediatrics to change its vitamin D recommendation. Even the new 400 international units dose is "a very conservative recommendation" to prevent rickets and vitamin D deficiency in all children, said Dr. Carol Wagner, a pediatrician at the Medical University of South Carolina and a member of the American Academy of Pediatrics Section on Breast-feeding Executive Committee. Breast-fed infants are especially at risk for insufficient vitamin D.

Vitamin D deficiency is more widespread than commonly thought. Earlier this year, researchers at Children's Hospital Boston found "suboptimal" levels of vitamin D in 40 percent of 380 otherwise healthy infants and toddlers, with 12 percent considered to be clinically deficient. Breast-fed infants were up to 10 times more likely to be deficient in vitamin D than their formula-fed counterparts, according to the study published in the Archives of Pediatrics and Adolescent Medicine.

Aside from infant formula and fortified milk, dietary sources of vitamin D are limited. It can be found in oily fish, fortified breakfast cereals, fortified orange juice and, of course, cod liver oil - one teaspoon contains 400 international units.

Historically, the main source of vitamin D has been sunlight, synthesized in the skin. Today, vitamin D deficiency is rampant because we're coated in sunscreen - in order to avoid skin cancer - or not outdoors enough to soak up the right amount, doctors say. But they aren't recommending sunbathing or tanning beds because they can't determine a safe amount of sunlight exposure to synthesize vitamin D in a given individual.

In individuals, vitamin D status differs by distance from the equator and race, with residents of the Northeast and people with more skin pigmentation being at increased risk of deficiency. Melanin, which gives skin its color, slows vitamin D synthesis.

"This is a silent deficiency. . . We used to think vitamin D had only to do with bones and it had only to do with children," said Wagner, co-author of a clinical report, "Prevention of Rickets and Vitamin D Deficiency in Infants, Children and Adolescents," appearing in the November issue of the journal "Pediatrics."

The American Academy of Pediatrics recommends vitamin D supplements in liquid or tablet form for:

Breast-fed and partially breast-fed infants, beginning in the first few days of life. Nearly all cases of rickets occur in breast-fed infants with dark skin who receive no vitamin D supplementation.

All non-breast-fed babies, as well as older children, who consume less than one liter a day of vitamin D-fortified formula or milk.

Adolescents who do not get 400 IU of vitamin D per day through foods. The 400 international units amount is standard for children's multivitamins.

Although some mothers' breastmilk can be deficient in vitamin D, it remains the best overall nutritional source for infants, the American Academy of Pediatrics maintains. Studies are underway to determine whether giving lactating women supplements helps produce vitamin D-rich milk. Vitamin D deficiency rickets isn't seen in formula-fed infants in the United States because formula and milk are fortified with 400 IU of vitamin D per liter.

Chronic vitamin D deficiency, spanning generations, may someday prove pivotal in explaining health disparities among races of people, Wagner said. "We see lots of long-latency diseases linked with vitamin D deficiency. There's interplay between vitamin D and the immune system."

The American Academy of Pediatrics' previous recommendation, issued in 2003, called for 200 international units per day. The new recommendation is based on new clinical trials and safety data on vitamin D.

Leigh Hopper Oberholzer can be reached at leighhop@gmail.com.