How much calcium is too much?
February 2, 2015
I am an endocrinologist who specializes in mineral metabolism, and about half the women I see in my practice don’t get enough calcium. But a small minority – about 5 percent of my patients – consume too much calcium.
Calcium is important for the prevention of osteoporosis, a dangerous thinning of bones that is particularly a problem in post-menopausal women. It is best to get your calcium in the food you eat, but many women take calcium supplements to boost their calcium consumption. A few women go overboard with calcium supplements. You probably have heard that taking too much calcium can increase your risk of kidney stones. What you probably don’t know is that excessive calcium intake may, possibly, cause heart problems.
Here’s how that might happen: Some of the excess calcium from supplements could make its way into fatty plaques in your arteries. These plaques narrow arteries, reducing the blood supply to heart muscle. The evidence for this concern is mixed. Some studies have, indeed, found an increased risk of heart problems associated with excessive intake of calcium from supplements, but other studies have found no such increased risk.
What is clear is that there is no benefit to bone health from consuming higher-than-recommended levels of calcium, so it’s best to stay at the recommended level. That means women who take calcium supplements should get in the habit of reading labels on food and calcium supplements and doing the math.
The Institute of Medicine recommended daily allowance of calcium for women ages 19 to 50 is 1,000 milligrams per day, and the upper level (safe) limit is 2,500 milligrams per day. The Institute’s recommended daily allowance of calcium for women ages 51 to 70 is 1,200 milligrams per day, and the upper level limit is 2,000 milligrams per day.
Here are some calcium tips:
- To determine how much calcium is in packaged foods, look at the percent of the recommended daily intake of calcium per serving and then add a zero. For instance, if a frozen pizza package says that a serving supplies 15 percent of the recommended daily calcium intake, you will get 150 milligrams of calcium from a serving of that pizza.
- Choose calcium citrate tablets. Calcium is available in different formulations, but calcium citrate is absorbed best.
- Calcium citrate can be taken with or without food, but it is best not to exceed 500 mg at a time.
- Try to stay close to the recommended daily allowance of calcium for your age, and do not exceed the upper-level limit.
- It’s best to get your calcium from food. Milk, cheese, and dark green leafy vegetables are good sources of calcium.