The US review, published in the December issue of Nutrition Reviews, looked at 24 controlled clinical trials, spanning the 1920s to the 1980s, on approximately 3,000 children in several countries.
Dr Philippe Hujoel, of the University of Washington in Seattle, who conducted the review, said that while vitamin D's role in supporting bone health has not been disputed, significant disagreement has historically existed over its role in preventing caries.
• 1950s: The American Medical Association and the US. National Research Council concluded that vitamin D was beneficial in managing dental caries. The American Dental Association said otherwise – based on the same evidence.
• 1989: The National Research Council, despite new evidence supporting vitamin D's caries-fighting benefits, called the issue ‘unresolved’.
• Current reviews by the Institute of Medicine, the US Department of Human Health and Service and the American Dental Association draw no conclusions on the vitamin D evidence as it relates to dental caries.
Dr Hujoel said: ‘Such inconsistent conclusions by different organisations do not make much sense from an evidence-based perspective.’
The trials he reviewed increased vitamin D levels in children through the use of supplemental UV radiation or by supplementing the children's diet with cod-liver oil or other products containing the vitamin.
The clinical trials he reviewed were conducted in the US, Great Britain, Canada, Austria, New Zealand and Sweden. Trials were conducted in institutional settings, schools, medical and dental practices, or hospitals. The subjects were children or young adults between the ages of 2 and 16 years, with a weighted mean age of 10 years.
The vitamin D question takes on greater importance in the light of current public health trends.
Vitamin D levels in many populations are decreasing while dental caries levels in young children are increasing.