May 23, 2012 at 6:50 PM ET
A study out Wednesday suggests that calcium supplements might increase the risk for heart attacks. But this research from Swiss scientists in the British journal Heart is just the type of experiment that often scares people unnecessarily and gives the science of epidemiology a bad name.
The Swiss scientists looked at a group of almost 24,000 people who participated in a European cancer and nutrition study over 11 years. There is the first tip that the research might be less than reliable. The study was set up to look at cancer risk and these scientists are “mining” the data to look for heart disease outcomes. What the researchers unearth is a confusing set of conclusions. In some people calcium intake seems to protect against heart disease. Indeed in the entire population there was no increase in total heart disease. But among those taking large amounts of supplements, they observe an increased number of heart attacks.
There has been concern for some time that too much calcium supplementation might cause heart disease because heart disease can result from a buildup of calcium in the arteries. Several studies of the issue have come to differing conclusions. What is not in doubt is that calcium in the correct amounts is critical for bone heath, but too much can cause health problems, possibly heart disease but for sure a risk of kidney stones and other health problems.
The study, though, should remind people that even though calcium is critical for bone health too much can be a hazard.
As Dr. Ethel Siris of New York-Presbyterian Columbia puts it, "People think more is better in this case in this case more is not better. Enough is enough.”
Getting the right amount of calcium can be a challenge. The government recommends that adults take 1000 mg a day of calcium and women over 50 take 1200. But it says no one over 50 should be taking more than 2000 mg a day.
It is easy to get too much calcium -- 22 percent of the adult US population takes calcium supplements.
Many foods have calcium. A cup of milk, a serving of cheese and a container of yogurt all have more than 300 mg. Some fortified breakfast cereals have as much as 1000 mg per serving.
But for bone health people do need calcium including a supplement. If they are not getting it from food or other sources they need a supplement – just not too much.