By Anthony J. Brown, MD
Vitamin D supplementation during infancy may protect children against the development of type 1 diabetes, according to a review of observational studies.
"The major finding is that (infants) supplemented with vitamin D were 29 percent less likely to develop type 1 diabetes in later life," lead author Dr. Christos S. Zipitis told Reuters Health.
He and his colleagues are now calling for clinical trials to confirm this finding, and to determine the optimal vitamin D formulation, dose, and duration of use.
Previous individual studies have not been consistent, said Zipitis, a paediatrician with the Stockport NHS Foundation Trust in the UK. "Our study provides the strongest evidence to date that vitamin D supplementation might be protective against subsequent development of type 1 diabetes."
In the last few decades, vitamin D supplementation has been falling, while the rate of type 1 diabetes has been rising, according to the team's report in the Archives of Disease in Childhood.
Furthermore, rates of type 1 diabetes are higher in areas with reduced sun exposure and during seasons with reduced sunlight, both of which suggest a link to vitamin D since sunlight triggers vitamin D production in the skin.
The present research, according to Zipitis, is a review of all studies on the subject to date. The researchers identified five studies that conformed to their selection criteria, covering a total of 6455 children.
"Vitamin D supplementation should be commenced from birth, for at least the first two years of life," Zipitis advised.
However, he emphasised, it is possible to have "too much of a good thing" and cautioned that excessive vitamin D supplementation can lead to problems.