Vitamin D deficiency: are we preventing the preventable?

Vitamin D supplementation: are multivitamins sufficient?

BACKGROUND

Public Health England advises 400 IU/day vitamin D supplementation for children over 1 year. Commercially available children's multivitamin and vitamin D supplements were surveyed to determine the vitamin D content.

METHODS

Multivitamins and vitamin D supplements marketed at children <12 years and sold by nine UK supermarkets and health supplement retailers were surveyed. Vitamin D content was determined from manufacturer's websites and product packaging.

RESULTS

67 multivitamins were surveyed, containing 0-800 IU/day vitamin D. Only 25%-36%, depending on the child's age, provided ≥400 IU/day vitamin D. Supplements containing only vitamin D or labelled as for 'healthy bones' typically had higher vitamin D content (57%-67% contained ≥400 IU/day).

CONCLUSIONS

Few multivitamin products supply the recommended 400 IU/day vitamin D. Clinicians need to be aware of this when recommending vitamin D supplementation and advise parents/carers to choose a product that contains ≥400 IU/day vitamin D.

Vitamin D, and Maternal and Child Health

Vitamin D has important roles in calcium metabolism and in the prevention of rickets and osteomalacia; low levels of 25-hydroxyvitamin D are common in the general population and amongst pregnant women. Whilst there is a wealth of observational evidence linking vitamin D deficiency to a wide range of disease outcomes, there are currently few high-quality randomised controlled trials to confirm any causal associations, although many are currently in progress. Furthermore, currently, the vast majority of published guidelines recommend standard supplemental vitamin D doses for children and pregnant women, yet there is increasing recognition that individual characteristics and genetic factors may influence the response to supplementation. As such, future research needs to concentrate on documenting definite beneficial clinical outcomes of vitamin D supplementation, and establishing personalised dosing schedules and demonstrating effective approaches to optimising initiation and adherence.