Almost 70,000 people participated in the US and Europe and found that the vitamin-mineral combination significantly reduced fractures by 8 per cent, and hip fractures by 16 per cent, according to results of a pooled analysis published in the British Medical Journal.
However, supplemental vitamin D on its own in daily doses equivalent to 10 to 20 micrograms had no effects on fracture prevention, said the study, led by researchers at Copenhagen University in Denmark.
?What is important about this very large study is that goes a long way toward resolving conflicting evidence about the role of vitamin D, either alone or in combination with calcium, in reducing fractures,? said co-author of the study, Professor John Robbins from the University of California, Davis.
History of use
The combination of vitamin D and calcium has long been recommended to reduce the risk of bone fracture for older people, particularly those at risk of or suffering from osteoporosis, which is estimated to affect about 75m people in Europe, USA and Japan.
The action of the nutrients is complimentary, with calcium supporting bone formation and repair, while vitamin D helps the body absorb calcium.
Indeed, the European Food Safety Authority (EFSA) accepted a health claim linking calcium and vitamin D to bone health in older women in 2008 following a disease-reduction claim application, made under article 14 of the European Union?s nutrition and health claims regulation and submitted by Abtei Pharma Vertriebs, a GlaxoSmithKline company.
The dossier claimed that chewing tablets with calcium and vitamin D improves bone density in women over the age of 50, and may reduce the risk of osteoporotic fractures and hip fractures. The proposed dosages were 1000mg calcium and 800 IU vitamin D3.
The new study reports that the bone boosting effects of vitamin D plus calcium may also extend to other age groups and to both sexes.
The researchers used data from seven major randomised trials of vitamin D with calcium or vitamin D alone, providing data from 68,517 people. The average age of the participants was 69.9, and 15 per cent of the people were men.
According to findings published in the BMJ, trials which used only vitamin D at a dose of 10 or 20 micrograms showed no significant reductions in fracture risk. When 10 micrograms of the vitamin was taken with calcium, however, reduced risks of fracture and hip fracture of 8 and 16 per cent, respectively. The combination was effective ?irrespective of age, sex, or previous fractures?, said the researchers.
?This study supports a growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing a variety of fractures,? said Robbins. ?Interestingly, this combination of supplements benefits both women and men of all ages, which is not something we fully expected to find. We now need to investigate the best dosage, duration and optimal way for people to take it,? he added.
Estimates suggest that in the absence of primary prevention the number of hip fractures worldwide will increase to approximately 2.6 million by the year 2025, and 4.5 million by the year 2050.
Osteoporosis weakens bone strength which increases the likelihood of hip fracture, a problem that increases with age.
No benefits from higher doses
Commenting independently on the results, Rob Dawson, senior communications officer for UK charity the National Osteoporosis Society told NutraIngredients: ?The research highlights the important role that vitamin D and calcium play in bone strength.
?Of course, many people will not need a calcium and vitamin D supplement. If you already get all the calcium that you need from your diet, and vitamin D from exposure to sunshine, then a supplement will not be necessary. There is no evidence to suggest that taking more than the required level will provide any extra benefit for your bones.
?However, when it comes to fracture prevention, this study does suggest a very small protective benefit of combined calcium and vitamin D supplementation in older people,? he added.
Source: British Medical Journal
2010; 340: b5463 Published online, doi:10.1136/bmj.b5463 |
?Patient level pooled analysis of 68 500 patients from seven major vitamin D fracture trials in US and Europe?
Authors: B. Abrahamsen for the DIPART (vitamin D Individual Patient Analysis of Randomized Trials) Group