Study: Vitamin D Cuts Diabetes Risk in Kids
Rate was 80% lower among Finns who took the supplement
THURSDAY, Nov. 1, 2001 (HealthDayNews) -- Children in a Finnish study who took vitamin D supplements early in life had a much lower risk of developing diabetes than those who didn't, researchers report.
Vitamin D apparently helps prevent the destruction of the insulin-secreting cells of the pancreas, and the new study adds evidence to support previous studies linking supplementation to a lower incidence of diabetes in children, says a report in the Nov. 3 issue of The Lancet.
Vitamin D is found in cod liver oil, salt-water fish and liver. An even more basic source is sunlight, which transforms cholesterol in the skin into the vitamin. The best known problem of vitamin D deficiency is rickets, the bone-weakening condition that was common in the smoky cities of the 19th and early 20th centuries. Just 10 to 15 minutes of exposure to sunlight three times a week is enough to provide the recommended dietary allowance of vitamin D, says the National Institutes of Health.
And although the study was done in northern Finland, where sunlight is at a premium in the winter, the results apply to the United States, says Elina Hyppönen, a research fellow at the Institute of Child Health in London who is lead author of the Lancet paper.
"Vitamin D supplementation is relevant for more southern countries," Hyppönen says. "After all, the exposure of small infants to sunlight is usually quite small."
Jill M. Norris, associate professor of medicine at the University of Colorado Health Sciences Center, who wrote an accompanying editorial, isn't quite sure about that.
"The problem is that the study included a very selective group of people, a small population in the far north," Norris says. "That may not represent what is going on in the United States."
But the Finnish study is the most definitive yet done, Norris adds. Earlier studies were retrospective, asking mothers to remember whether they had taken vitamin D during pregnancy or whether their children were given supplements years earlier.
The new study started at birth and followed almost 11,000 children for more than a decade. The incidence of diabetes was 80 percent lower in children who had the recommended amount of vitamin D in their first year of life -- 2,000 international units a day, generally from cod liver oil -- than in those who did not, the researchers say.
European countries generally recommend vitamin D supplements for children, Hyppönen says, primarily to prevent rickets, which was a problem as late as the 1950s. "In Finland, all children receive it," she says.
"The interesting thing from the United States' point of view is that we do not recommend that children take vitamin D supplements in the first year, while it is recommended in other parts of the world," Norris says.
Side effects of excess vitamin D intake also have to be considered, she says. These include nausea, constipation and weight loss, with kidney and heart damage possible with major overdoses. The Finnish report does not mention those risks, Norris notes.
"My opinion is that the definitive study has not yet been done," she says. "I don't think the studies done to date warrant changing the pediatric recommendations."
What To Do
Any parent considering vitamin D supplementation for a child should talk to a pediatrician about the best way of insuring an adequate intake of the vitamin and about avoiding the ill effects of an overdose.
For information about vitamin D, go to the National Library of Medicine. To learn more about diabetes, try the National Institute of Diabetes and Digestive and Kidney Diseases.