Many women have questions about calci­um supplements. Should you be taking a daily supplement? The answer is yes, no, or maybe, depending on what you are eating and what other supplements you are taking.

Jeanne, age 62, was trying to lower her risk of osteo­porosis, which debilitated her mother, by taking calcium supplements and getting regular exercise. She sought my advice about prevention of osteoporosis. I instructed her to write down everything she ate and drank for three days and bring in all the vitamins and supplements she was taking so I could examine them.

On review of her diet, I noted that Jeanne was con­suming 700 milligrams (mg) of calcium per day from various foods and drinks. She took a 600 mg calcium supplement twice a day. Her once-a-day multivitamin contained 500 mg of calcium. Altogether her diet and supplements totaled 2,400 mg of calcium.

For women over age 50 and men over age 70, the lat­est recommendation from the Institute of Medicine is 1,200 mg of calcium per day from all sources. At 2,400 mg per day, Jeanne was taking double what she needed, which could have a negative impact on her health. Ex­cess calcium ends up in the urine, increasing the risk of kidney stones.

In addition, recent research suggests that a daily cal­cium intake of more than 2,000 mg may increase the risk of heart attacks, though it should be noted that studies on the subject of calcium supplements and car­diovascular risks for angina, heart attacks, strokes, and sudden death are inconclusive. Some studies found no association between calcium intake and cardiovascular problems, whereas others did find an association. The studies showing an association with heart attacks raises the possibility that excess calcium intake may increase cardiovascular risks. Therefore the Institute of Medi­cine in 2010 lowered its daily calcium recommendations for men and women over 50 to 1,200 mg and set the upper limit at 2,000 mg.

In Jeanne’s case, her primary care provider had rec­ommended she take a supplement without obtaining a dietary history or asking what else she was taking. With an average of 700 mg in her diet and 500 mg more from her multivitamin, Jeanne already met the 1,200 mg recommended target. Taking the separate calcium supplement put her way over what she needed. She did not need a calcium supplement at all.

Jeanne’s case illustrates the importance of exam­ining your current diet and supplement use to learn how much calcium you are already getting and es­tablish the correct dosage. The following are some additional tips to help you understand calcium sup­plementation.

  • Be aware of supplement serving size. If the serving size is three tablets and you are only taking one, you are getting only one-third of the amounts listed.
  • Be dynamic in your supplement use and dose. Don’t take the supplement each day unless you are eating and drinking the same food items every day. For instance, you may have yogurt every morning for breakfast except on Satur­day, when you have eggs. You won’t need to take a calcium supplement if you are getting a similar amount of calcium in your food (in this case, yogurt). On Saturday, when your break­fast has no calcium source, add one—such as cheese on your eggs—or drink fortified orange juice, almond milk, or a latte; or you can take a calcium supplement on that morning.
  • You are probably taking too much calcium already. If you are just taking a 1,000 or 1,200 mg calcium supplement every day, you are probably getting too much. Even if you don’t consume dairy products, the average American adult consumes 300 to 400 mg of calcium from food each day. That means you don’t need more than 800 mg of calcium supplements, divided into two daily doses.

Calcium Supplements and the Risk of Heart Attack

Calcium supplements might increase the risk of having a heart attack, according to research published in the journal Heart. (1) The study included data from nearly 24,000 German men and women who took part in the European Prospective Investigation into Cancer and Nutrition study. All participants were between ages 35 and 64 when they joined the study between 1994 and 1998. They recorded their food and supplement intake throughout the study and were followed for an average of 11 years.

The researchers found that participants who took calcium supplements were 86 percent more likely to have a heart attack than those who did not. Interestingly—in contrast, participants who had a high dietary calcium intake (from foods rather than supplements) were about 31 percent less likely to have a heart attack compared to individuals with a low dietary calcium intake.

Why the discrepancy? Scientists aren’t sure—but they speculate that calcium supplements might cause a sudden surge of calcium into the system and this calcium could end up contributing to the plaque that lines the arteries. Dietary calcium, on the other hand, is consumed in small amounts spread throughout the course of the day and is likely absorbed more slowly.

Of course, this is just a theory and will need to be confirmed through further research.The results of this study have generated a great deal of controversy in the medical community, but it’s not the first study to find a link between calcium supplements and heart attacks. (2) The bottom line—until research confirms or refutes the risks of calcium supplements, it’s probably wise to use caution. If you’re concerned about bone health, focus on increasing your dietary intake of calcium through foods such as sesame seeds, chia seeds, dark leafy greens, dairy products, flaxseeds, oranges, and broccoli. Most of us don’t need huge doses of calcium. Work with your doctor to determine your individual calcium needs. If you do choose to supplement, be sure to maintain regular preventive health screening to stay on top of any risk factors for heart disease.

References:

  1. Li K, Kaaks R, Linseisen J, Rohrmann S. 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; 98: 920-925.
  2. Bolland MJ, Grey A, Avenell A, et al. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis. British Medical Journal, 2011; 342: d2040 DOI: 10.1136/bmj.d2040