In a large review of studies, researchers have found almost no evidence that taking vitamin D supplements has any effect in preventing osteoporosis in middle-aged adults.

The analysis, published online last week in The Lancet , included 23 randomized trials that measured the effect of vitamin D on bone density at four sites — spine, neck, hip and forearm — and included more than 4,000 generally healthy participants whose average age was 59.

The studies used dosages that varied from 500 units a day to 800 or more, given on varying schedules. In some studies, the subjects were given calcium as well.

Neither the pooled data nor any single study showed a significant increase in bone density across all four sites, and the overall number of positive results was no better than would be expected by chance.

The large number of participants and the wide range of regimens give the review’s conclusions considerable strength.

The authors write that the widely believed idea that vitamin D promotes bone mineralization is probably incorrect.

“We’re not talking about people who are really vitamin D deficient,” said the lead author, Dr. Ian R. Reid, a professor of medicine at the University of Auckland in New Zealand. “But for healthy people focused on osteoporosis prevention, vitamin D does not make a positive contribution.”

Bron: http://well.blogs.nytimes.com/2013/...sis/?ref=health (www.nytimes.com)

Mening: Sommige onderzoeken bevestigen dat het nemen van vitamine D juist wel effect heeft in de bestrijding van osteoporose. Dit onderzoek wijst juist het tegenovergestelde uit, dat het geen effect heeft. Net zoals een tekort aan vitamine D, is ook een teveel niet gezond. Ik denk dat het belangrijk is voor volwassenen, die nu niet weten of ze extra vitaminen moeten nemen of niet, beter voor zichzelf uit kunnen maken wat zij belangrijk vinden.