Calcium Supplements: Are They Safe?
In July, a meta-analysis of the effect of calcium supplementation on heart attacks was published in the British Medical Journal (1). They found that people taking calcium supplements were more likely to have a heart attack. People have asked me if I think this means vegans should not supplement with calcium.
If you look at the study (the full paper is available for free at the link in the abstract below), they found that the increased risk of heart attack was limited to people who started out with a dietary calcium intake of 700 mg/day or more. Most vegans do not get that much calcium through foods. In most of the studies they examined, the level of calcium supplementation was substantially higher than 500 mg.
This study indicates that if you are an adult who gets 700 mg of calcium from your diet (including fortified foods), you probably shouldn’t take more than about a 300 mg supplement of calcium per day.
The DRI for calcium for ages 9 to 18 is 1,300 mg. This meta-analysis was conducted on older people trying to prevent osteoporosis and is probably not applicable for teenagers, whose bones are still building.
The DRI for calcium for people over 50 is 1,200. My recommendation for people in this age group who want to meet the DRI is to get at least 700 mg per day through foods and only supplement enough to make up the difference.
It’s worth noting that some observational studies of calcium intake (from foods, not supplements) have shown higher intakes to be protective against heart disease.
1. Bolland MJ, Avenell A, Baron JA, Grey A, MacLennan GS, Gamble GD, Reid IR.
Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010 Jul 29;341:c3691.