Do Calcium Supplements Cause Heart Disease?

Are you confused about calcium? We can’t blame you. In the 1980s, about a fourth of women over 60 were taking calcium supplements. Among their daughters who’ve now reached this age, over 60% rely on calcium supplements to boost what their diet provides.* But in just the past few months, health news headlines have led women in all directions about whether to throw away their calcium supplements or buy more.

From  CBS News:

“Calcium  supplements may not be heart healthy.”

From the Washington Post:

Calcium supplements could increase risk of heart disease, new study finds.”

And then, within days of those articles, the winds shifted, and in Healthday a new headline read:

“Review Says Calcium Supplements Won’t Harm the Heart”

That headline and many like it came from the announcement that two important professional organizations, the National Osteoporosis Foundation and the American Society for Preventive Cardiology, had jointly made the following announcement: “Discontinuation of supplemental calcium for safety reasons is not necessary and may be harmful to bone health when intake from food is suboptimal” (Annals of Internal Medicine, Oct. 2016).

So what should women be doing? Here Dr. Sparks answers some of our patients’ questions.

I am careful about my diet. How likely is it that I am not getting enough calcium from food? Only about a third of women between 30 and 50, and less than 10% of older women, reach the recommended allowance for calcium per day from food sources.* Deciding whether you need calcium supplements depends on carefully evaluating how much calcium your diet really provides. I recommend a food journal. Besides tracking your calcium intake for a few days, it’s a powerful weight control tool. The National Osteoporosis Foundation also provides a shortcut for estimating your daily calcium intake.

I don’t care for milk or my digestion cannot tolerate milk and dairy products, but now I am worried that my calcium tablets could cause heart disease. Should I stop taking them? That depends. Most health professionals agree that food sources of calcium are much better than supplements. No pill can duplicate the benefits of a healthy diet. Dairy products are the richest sources of calcium. Dark green leafy vegetables like collards, spinach, kale and broccoli—as well as beans, peas, and lentils—are good non-dairy calcium sources.  A Google search can provide other suggestions.

If a woman knows that her diet does not provide 1000 mg. of calcium each day (1200 mg. if you have reached menopause), then I recommend to my patients that they follow the National Osteoporosis Foundation’s guideline. Those who are unable to increase the calcium they get from food can safely use a supplement as long as their total daily intake of calcium (food and supplement together) is not more than 2000 mg. /day.  (Use a food tracker or see the link above for estimating calcium intake).

Why is there so much disagreement about this? There is still much we don’t know about the complex relationship between calcium and vitamin D intake, bone loss, and other health risks. But one fact is certain. You need adequate amounts of calcium in your diet throughout your lifespan to reduce your risk of osteoporosis. Calcium is essential for regulating the heartbeat, nerve function, and blood clotting. The body can “borrow” calcium from the bones, but its ability to return the borrowed calcium to bones depends on many factors. Up to about age 30, your body builds more bone than it breaks down. Building strong bones early in life is the best osteoporosis defense. As you age, you lose bone regardless of your calcium intake or other factors. The goal then shifts toward trying to slow that bone loss.

The two research groups that created the October headlines disagree about which scientific studies are most reliable—those that show no relationship between calcium supplements and heart disease vs. those that show a small increased risk for calcium deposits in arteries. But the groups agree on what’s important for women. A diet rich in calcium is the best choice. Without that, calcium supplements at moderate levels are recommended to prevent osteoporosis and should be safe.

Is this your recommendation for every woman?

Yes, I encourage each of my patients to get the recommended amount of calcium, preferably from food, but by adding supplements if necessary. For a woman who been diagnosed with cardiovascular disease, I recommend she consult her cardiologist or internist before taking calcium supplements. But other risks for osteoporosis are very individual—such as family history, history of smoking, exercise habits, and the results of bone density tests. If a woman is prematurely or rapidly losing bone strength, we will talk about the benefits and risks of treating her osteoporosis with hormone replacement and/or other medication. Bone fractures cause pain, disability, loss of independence, and can lead to premature death. Osteoporosis can sneak up on you as you age. We want to discuss your personal risk factors at your annual well-woman exam.

*National Center for Health Statistics