Do you really need calcium supplements for strong bones?

Calcium from food, such as from dairy, plays a recognised role in building bone mass and is physiologically beneficial for bone health. Food is preferred over pills, although the effect of dietary calcium on fracture prevention has not yet been demonstrated conclusively in prospective studies.

For young, healthy women before menopause, calcium supplements miss the mark entirely. Both calcium alone and calcium combined with vitamin D show no measurable difference in bone density of the hip or spine compared with placebo in that group. If you are in that phase of life, you are better off focusing on getting enough calcium through your daily diet.

In people aged 50 and older, the picture changes. A combination of calcium and vitamin D reduces bone loss and lowers the risk of fractures by an average of 12%. With good adherence to treatment, that risk reduction rises to 24%, particularly at doses of at least 1200 mg of calcium and 800 IU of vitamin D per day. Postmenopausal women also benefit from improved bone density at multiple sites and fewer hip fractures. Calcium and vitamin D added to dairy products appears to be more effective in this regard than separate supplements.

There is an important safety signal: in a large study involving more than 36,000 women, the combination of 1000 mg of calcium and 400 IU of vitamin D per day increased the risk of kidney stones by 17%. That dose also did not significantly reduce fractures. Anyone considering supplementation would do well to discuss this with their general practitioner, especially if they have a history of kidney stones.

Exercise considerably strengthens the effect of supplementation. In women with bone loss, a combination of high-intensity interval training and vitamin D produced greater improvements in bone density than either intervention alone. And postmenopausal women who exercise on top of taking calcium and vitamin D see significantly better results than with supplements alone.