Vitamin D and calcium are important for bone health. With regards supplementation with these nutrients to prevent fracture the research to date has often been conflicting and inconclusive. However, very recent evidence published in the British Medical Journal (1) has found that supplementation with both of these nutrients together is effective in fracture prevention.
The authors of the study conclude “This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 µg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures”. The research (1) looked at data from seven major randomised trials with a total of 68,517 participants (men and women aged between 47 and 107 years old).
In a press release (2) professor John Robbins, one of the study authors said: “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,” “Our WHI research in Sacramento included more than 1,000 healthy, postmenopausal women and concluded that taking calcium and vitamin D together helped them preserve bone health and prevent fractures. This latest analysis, because it incorporates so many more people, really confirms our earlier conclusions.”
Fractures are a major cause of disability, loss of independence and death for older people - fractures can often be the result of osteoporosis, a disease characterized by low bone mass and bone fragility. Professor Robbins says (2) “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,” “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.”
In an editorial (3), written about this recent research, in the British Medical journal Dr Sahota writes about the implications of the current evidence in clinical practice saying: “Although the evidence is still confusing, there is growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing [non-vertebral] fractures. Higher doses are probably necessary in people who are more deficient in vitamin D, and treatment is probably more effective in those who maintain long term compliance. Further studies are needed to define the optimal dose, duration, route of administration, and dose of the calcium combination”.
As mentioned in many of my previous posts on vitamin D, most of the UK population are probably suffering from insufficient or deficient vitamin D levels.
Fragility fractures cause excess mortality, substantial morbidity, and related health and social issues and financial problems in older people. Risk of fracture is higher in institutionalised older people than in community dwelling older people of the same age. This reflects a greater risk of falls and lower bone mineral density in these populations. Vitamin D insufficiency and deficiency is common in older people, particularly in residential and care homes.
The current study (1) suggests that “Daily calcium and vitamin D supplementation, even at doses as low as 10 µg of vitamin D daily, significantly reduces the risk of fracture” the effective dose of supplements in the study was 1000mg calcium + 20micrograms vitamin D (the equivalent of 800iu). Recent work with vitamin D suggests that up to 5000iu daily for adults may be required to keep blood levels of vitamin D optimal. I would suggest most individuals in the UK would require around 2000iu vitamin D daily. Higher doses may be useful but I would not recommend such a regimen unless under the supervision of a medical doctor who can monitor blood levels.
(1)The DIPART (vitamin D Individual Patient Analysis of Randomized Trials) Group. 2010. Patient level pooled analysis of 68 500 patients from seven major vitamin D fracture trials in US and Europe. BMJ. 340:b5463 doi:10.1136/bmj.b5463
(2)Press release: University of California – Davis – Health System (2010, January 15). Benefits of calcium and vitamin D in preventing fractures confirmed. ScienceDaily. Retrieved January 15, 2010, from http://www.sciencedaily.com/releases/2010/01/100114143325.htm
(3) Sahota O. 2010. Reducing the risk of fractures with calcium and vitamin D. BMJ. 340:b5492
Written by Ani Kowal
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