Vitamin D Supplements May Protect Against Diabetes in Kids

From the WebMD Archives

Nov. 1, 2001 -- In the past, research has pointed to a link between vitamin D and diabetes in kids. Now a new study suggests that giving vitamin D supplements to children may help protect them from high blood sugar.

Researchers followed 12,000 Finnish children from birth. They found youngsters given vitamin D supplements during the first year of life were less likely to develop type 1 diabetes, a form of the disease that, almost always, is seen first in children or young adults. It requires multiple injections everyday with insulin, the hormone that keeps blood sugar from rising too high.

Most of us get enough vitamin D from our diet and from being in the sun, which helps the body make it. Finland is the perfect place to study the effects of vitamin D on the body, as people there may not be getting the sunlight required to make enough of the nutrient. Supplementation is often recommended because Northern Finland may get as little as two hours of sun each day during the winter.

Researchers say the findings could help explain the very complex and little-understood causes of the disease, once known as juvenile-onset diabetes. Genes, the immune system, and environmental factors are all believed to be involved, but their exact roles are not known.

"Only a very small number of those with a genetic susceptibility to type 1 diabetes go on to develop the disease," lead researcher Elina Hypponen, PhD, of London's Institute of Child Health, tells WebMD. "Animal studies and several other studies suggest that inadequate vitamin D may be linked to diabetes risk, and that is why we did this study."

Hypponen and colleagues collected information on vitamin D supplementation from approximately 12,000 children in northern Finland born in 1966. Children who had the recommended supplements of vitamin D (usually in the form of cod-liver oil) were found to have an 80% reduction in diabetes risk, compared to those receiving less than the recommended dose. The findings were reported Nov. 5 in the journal The Lancet.


Epidemiologist Jill M. Norris, PhD, who also studies possible causes of type 1 diabetes, says the Finnish findings are intriguing, but preliminary. More study is needed, she adds, to confirm a link between vitamin D deficiency and avoiding the disease. Norris is with the University of Colorado Health Sciences Center.

"We are still researching this, and we have to be very careful about the message we send," she says. "If someone is concerned that their baby might not be getting enough vitamin D, they should talk to their pediatrician."

Because vitamin D can be highly toxic and even deadly when too much is ingested in supplement form, both researchers warned that mothers should not supplement their babies' diets without checking with their doctors first. In the U.S., where children tend to get all of the vitamin D they need through exposure to sunlight and diet, supplementation may do more harm than good, Norris says.

But in an editorial evaluating the Finnish study, Norris also warns that several well-intentioned and important public health initiatives may be coming together to reduce natural vitamin D exposure in children. The emphasis on breastfeeding for longer periods may mean fewer babies are getting adequate vitamin D in their diets, since baby formula and milk are fortified with vitamin D. And warnings to keep babies out of the sun and use sunscreen on toddlers at all times may mean fewer children are getting vitamin D from sunlight.

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