Vitamin D and calcium increase bone strength

A combined supplementation of vitamin D and calcium is effective in increasing the bone mineral density of post-menopausal women, even when calcium intakes are adequate, says a new Finnish study.

In the randomized controlled trial, 593 post-menopausal women were randomly selected for bone mineral density (BMD) measurements, with half of the women receiving daily vitamin D (800 IU) plus calcium (1 gram) supplements for three years, while the other group received placebo (1). The results showed that the total body BMD increased significantly more in the group who received supplementation compared with women who received no intervention. Moreover, women who most fully participated in the supplementation study, taking at least 80 percent of the supplements, showed the greatest benefits. The researchers commented that daily vitamin D and calcium supplementation has a positive effect on the skeleton in postmenopausal women, even in those with adequate nutritional calcium intake.

Earlier, a Danish meta-analysis of seven randomized controlled trials with 68,517 people (mean age 69.9 years) from the US and Europe found that the vitamin-mineral combination significantly reduced fractures by 8 percent, and hip fractures by 16 percent (2). Supplemental vitamin D on its own in daily doses equivalent to 10 to 20 micrograms had no effects on fracture prevention. The researchers concluded that daily supplements which combine vitamin D and calcium may reduce the risk of fractures for everyone, regardless of age or gender. However, results from another trial did not back up the positive effect of lowering the risk of fractures (3).

The combination of vitamin D and calcium is recommended to reduce the risk of bone fracture for older people, particularly those at risk of or suffering from osteoporosis. The action of the nutrients is complimentary, with calcium supporting bone formation and repair, while vitamin D helps the body absorb calcium. In 2008, the European Food Safety Authority (EFSA) accepted a health claim linking calcium and vitamin D to bone health in older women.

1. Karkkainen M. et al. Effect of calcium and vitamin D supplementation on bone mineral density in women aged 65-71 years: a 3-year randomized population-based trial (OSTPRE-FPS). Osteoporosis International. 2010, 21(12):2047–2055.
2. Abrahamsen B. et al. Patient level pooled analysis of 68,500 patients from seven major vitamin D fracture trials in US and Europe. BMJ. 2010; 340:b5463.
3. Salovaara K. et al. Effect of vitamin D3 and calcium on fracture risk in 65- to 71-year-old women: A population-based 3-year randomized, controlled trial – the OSTPRE-FPS. Journal of Bone and Mineral Research. 2010; 25(7):1487–1495.