Men -- but not women -- who take calcium pills may face a higher risk of dying from heart disease, a new study suggests. The study looked at data on 388,000 men and women. They were part of a study on diet and health. They were 50 to 71 years old when the study began in 1995. Researchers kept track of people for an average of 12 years. In that time, about 7,900 men and 4,000 women died of heart disease or stroke. Of this group, 51% of men and 70% of women were taking calcium pills. Researchers calculated that men taking 1,000 milligrams of calcium daily had a 20% increased risk of heart-disease death. There was no increase in risk for women who were taking calcium pills. Calcium obtained from food or drinks did not affect death risk for men or women. The study could not show whether taking calcium pills actually caused the increased risk. Researchers said more study was needed. The journal JAMA Internal Medicine published the study. HealthDay News wrote about it February 4.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Millions of women and men take calcium pills to strengthen their bones and prevent osteoporosis. Whether taking calcium pills is good, neutral or bad for the heart is a matter of conflicting studies and lively debate. But recently more studies have shown the potential danger. The results of this new study sound another note of caution.

Men who took calcium pills had a 20% higher risk of dying from heart or blood vessel disease than men who did not take calcium pills. This was a large observational study. These types of studies can only show a link between certain factors or behaviors. They can't show that one thing caused the other. So this study does not prove that calcium pills cause a higher death rate from heart or blood vessel diseases.

In this study, women who took calcium pills did not have a higher death risk. Why men and not women? It may be related to the age when a person starts taking calcium pills. Could a sudden increase in calcium intake affect the arteries in the heart and elsewhere in the body?

Women tend to start calcium pills at younger ages than men. Many of them begin before menopause. Their bodies have long adjusted to the increased calcium. Men who take calcium pills usually start after age 60, when they are already at higher risk of heart and blood vessel disease.

In support of this theory, Australian researchers looked at results from a large study of calcium pill use in women. None of the women were taking calcium pills at the time the study started. Half took a calcium-vitamin D pill and the other half took a placebo (fake pill). The women who took the calcium-vitamin D pill had a 20% higher risk of having a heart attack during the study. They had a 17% higher risk of stroke.

What Changes Can I Make Now?

Getting enough calcium remains as important as ever. But how much calcium is "enough"? It depends on whom you ask.

The U.S. government recommends 1,000 milligrams (mg) a day from ages 19 to 50 and 1,200 mg a day after that. In the United Kingdom, health experts recommend that everyone over age 19 get 700 mg a day. The World Health Organization says that 500 mg daily is enough.

Given the uncertainty about the balance of benefits and risks of calcium pills, it's probably best not to rely on them to keep your bones strong. Getting calcium from food is your best bet.

You can get 1,200 mg of calcium from food without too much trouble. A cup of low-fat yogurt, a glass of low-fat milk, and a serving of sardines deliver a combined 1,025 mg.

Calcium doesn't work alone. Healthy bones and bodies also need:

• Vitamin D -- Unlike calcium, vitamin D is hard to obtain in large amounts from foods and drinks. Ten to 15 minutes of sunlight daily is the natural way to get your vitamin D. But for skin health, many people avoid the sun. A pill containing 1,000 international units (IU) of vitamin D each day is more than enough and still safe.
• Vitamin K -- It doesn't receive the same attention as vitamin D because it's so easy to get plenty of vitamin K. Just eat green leafy vegetables, especially spinach, broccoli, Swiss chard and kale.
• Weight-bearing exercises -- Examples include walking, jogging, tennis and weight training. Exercise is as important as the right nutrients to maintain bone health.

Also, don't smoke. And if you do drink alcohol, do it in moderation. Smoking and excess use of alcohol increase your risk of osteoporosis.

What Can I Expect Looking to the Future?

Until recently, many people held the belief that getting extra calcium improves health. And calcium pills have had a reputation of being safe. Now we are not so sure.

Calcium pills should be viewed in the same way as all supplements. Take them only if you absolutely can't get enough from your diet.

This appears to be especially true for men. Besides the potential greater risk of heart problems, high-dose calcium pills may also increase a man's risk of prostate cancer.