Vitamin D requirements in the first year of life.

PURPOSE OF REVIEW

To understand the basis for current recommendations for vitamin D supplementation in childhood and the differences between the recommendations published by major expert committees, using the Medline engine of the US National Library of Medicine and the National Institutes of Health.

RECENT FINDINGS

Recent recommendations published by major national expert committees are essentially based on expert opinion (a relatively low level of evidence). Randomized controlled trials are very few, and there are no systematic reviews or meta-analyses on the topic. Most trials have examined the question of whether a specific daily vitamin D dose is capable or not to prevent rickets (by studying surrogate markers of rickets). There are no trials that have systematically attempted to determine the upper limit of daily vitamin D dose beyond which its toxic effects may appear. Whether or not outcomes such as osteoporosis (or low bone mass) and specific types of cancer may be prevented by 'generous' vitamin D supplementation is unclear and mostly based on indirect epidemiologic data not clearly substantiated by randomized controlled trials

SUMMARY

The dose of daily vitamin D supplements needed to prevent rickets is probably much lower than that recommended by most expert committees. Whether higher doses of daily vitamin D supplements may or may not prevent other poor outcomes such as adult osteoporosis or specific types of cancer is not yet known.