By David Richards, D.C., M.D.

Q: Should otherwise healthy people take calcium supplements to prevent osteoporosis and bone fractures?

A: For men and women eating a healthy diet, there is no need to take calcium supplements or multi-vitamins with calcium in them. Calcium supplements increase the risk of cardiovascular events, especially heart attacks.1,2

Calcium supplements cause more cardiovascular events than the small number of fractures they prevent, so they have a net negative effect. To help keep your bones strong, you need to optimize calcium intake from the diet

Specifically:

People who take calcium supplements in addition to other supplements are 86 percent more likely to experience a heart attack than people who do not take any supplements.3

People who take calcium supplements by themselves are 139 percent more likely to experience a heart attack than people who do not take any supplements.3

1000 women need to be treated with calcium supplements for 5 years to prevent 3 fractures.1,2

Calcium should be obtained from food, not pills, because the calcium in food is absorbed slowly throughout the day and the calcium from pills floods the bloodstream with calcium in a short period of time. This can cause an increase in the level of calcium in the blood,4 leading to calcification of arteries, including those in the heart. Calcification of the arteries raises the chances of a heart attack. Calcium supplements also increase the risk of kidney stones by about 20 percent,4 and double the risk of abdominal conditions resulting in admission to a hospital.5 There is no evidence that calcium from food has any negative effects, so if you are following the diet recommended by the NHA, you are getting sufficient calcium without the risk of any harm. Calcium supplements and multivitamins with calcium in them cannot be considered safe, despite what the message on the pill bottle may say.

References:

1. Bolland MJ, Grey A, Gamble GD, et al. Calcium and vitamin D supplements and health outcomes: a reanalysis of the Women’s Health Initiative (WHI) limited-access data set. Am J Clin Nutr 2011;94:1144-9.

2. Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ 2010;341:c3691.

3. Li K et al. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition Study (EPIC-Heidelberg). Heart 2012. DOI:10.1136/ heartjnl-2011-301345.

4. Karp HJ, Ketola ME, Lamberg-Allardt CJ. Acute effects of calcium carbonate, calcium citrate and potassium citrate on markers of calcium and bone metabolism in young women. Br J Nutr 2009;102:1341e7.

5. Lewis JR, Zhu K, Prince RL. Adverse events from calcium supplementation: relationship to errors in myocardial infarction self-reporting in randomized controlled trials of calcium supplementation. J Bone Miner Res. 2012;27:719e722.