Vieth, R. The role of vitamin D in the prevention of osteoporosis. Ann. Med. 37, 278-285

Department of Nutritional Sciences, Laboratory Medicine and Pathology, University of Toronto, Ontario, Canada.
Annals of Medicine (Impact Factor: 3.89). 02/2005; 37(4):278-85. DOI: 10.1080/07853890510007313
Source: PubMed


The need for vitamin D to prevent rickets was the drive for selection of lighter skin color in temperate climates. Anthropologists also know that as human populations developed more sedentary lifestyles, this coincided with a decline in bone quantity, quality, and fracture resistance. Since osteoporosis occurs after the reproductive years, there is no way that natural selection could have adapted our biology to prevent it. However, osteoporosis can be largely prevented by optimizing physical activity, and the vitamin D-related factors of environment, and nutrition. The role of vitamin D3 in osteoporosis is conclusively established from a very simple meta-analysis of the four randomized, placebo-controlled clinical trials into the effect of 20 microg (800 IU) per day. These have all demonstrated that this dose prevents approximately 30% of hip or non-vertebral fractures compared to placebo, in adults older than 65 years. Intakes less than this have never been found effective. The lowest average serum 25-hydroxyvitamin D concentration in any study demonstrating fracture reduction was 74 nmol/L. Thus, 25-hydroxyvitamin D levels in older adults should exceed this amount. The role of vitamin D supplementation is to provide humans with the nutrient in an amount closer to our species' biological norm. This amount of vitamin D results in the optimal function of many aspects of health, including balance and muscle strength that lessen the risk of fracture beyond what is possible via the quality and quantity of bone itself.

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    • "Sunshine therefore remains the principal natural source of vitamin D, providing 80–90% of the requirement in the absence of fortified food. Although exposing a part of the body (for example the face, trunk and arms) to the sun in summer can provide 10 000 IU of vitamin D in less than half an hour, this supply disappears within a few weeks and cannot readily be replenished throughout the year except in tropical countries (Vieth, 1999; Hollis, 2005; Vieth, 2005; Diffey, 2010). Moreover, elderly and dark-skinned subjects are less able to synthesize vitamin D than young, light-skinned subjects who, if they protect themselves too much from the sun (by clothing or sun-block), may also rapidly find themselves in a state of vitamin D insufficiency (Vieth, 1999; Armas et al., 2007; Binkley et al., 2007). "
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    • "Low serum concentrations of vitamin D is widespread in the U.K [6] and moderate vitamin deficiency in older people results in poor bone and muscle strength [7,8]. Serum 25 (OH) vitamin D concentrations that correlate with clinically significant effects on muscle function and fracture prevention is at least 70 nmol/L [9]. It is still unclear whether addition of calcium/vitamin D supplements leads to an incremental benefit in patients taking bisphosphonates and whether achievement of serum level of vitamin D of at least 70 nmol/L has an impact on the skeletal response to bisphosphonates. "
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