How much calcium intake is too much?

Photo by an_vision | Unsplash

By Howard LeWine, M.D.
Posted on July 12, 2026

Q: I take a 500 mg calcium supplement every morning. I drink about three glasses of milk daily, plus the milk on my breakfast cereal. Is this too much calcium? Is there any danger from taking in more calcium than you need? Can it cause calcium buildup in my heart?

A: Yes, you are taking in more calcium than you need to keep your bones and the rest of your body healthy.

The current recommendation in the United States is 1,000 milligrams (mg) of calcium per day from ages 19 to 50 and then 1,200 mg per day after age 50.

However, these amounts are probably more than we actually need. For example, in the United Kingdom, the recommendation is only 700 mg per day. The World Health Organization says that 500 mg daily is enough.

I estimated your calcium intake based on the information you provided. Eight ounces of milk contains 300 mg. Three glasses of milk is 900 mg. You are getting additional calcium from other foods. Adding the 500 mg supplement each day, your total daily consumption of calcium including other food sources is probably more than 1,700 mg per day.

Regarding your second question, does ingesting that much calcium adversely affect your health? No definitive answer on that one. Some studies have shown that men who take in very high amounts of calcium have an increased risk of dying from prostate cancer.

Other studies suggest that women who ingest high doses of calcium might have more heart disease and may have a slightly increased risk of ovarian cancer. But none of these studies are conclusive.

The effect of calcium on the heart and circulatory system is a very interesting question. When fatty deposits build up in our arteries, they pull out calcium from the bloodstream. The calcium gets deposited inside the fatty deposits, and the calcium there makes arteries stiff. The calcium in our blood comes from our bones. There is no evidence that diets very rich in calcium harm the heart.

The known danger of taking too much calcium is elevated levels of blood calcium called hypercalcemia. If untreated, this can lead to fatigue, kidney problems and mental confusion. But this is actually quite uncommon, and usually is the result of taking high dose supplements of both calcium and vitamin D.

Unless your doctor specifically recommended the calcium supplement, you probably don’t need it. But be sure you are getting enough vitamin D. I personally recommend a multiple vitamin or a 1,000 IU vitamin D supplement daily.

Like calcium, more is not necessarily better. Vitamin D enhances the absorption of calcium from the intestine into the blood, so a moderate intake of both is best.

Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For more consumer health information, see health.harvard.edu.