For years, women have been told that they need extra calcium after menopause to boost bone strength. The advice: Eat a calcium-rich diet and take supplements, too.
Now a large study in the British Medical Journal suggests that too much calcium from any source may be risky, after previous studies called into question the value of supplements over dietary sources.
The Study: Increased Risk Of Death
The most recent study was conducted among 61,433 Swedish women with a median age around 55 at the outset. It found that those who had 1,400 mg of calcium or more a day had a 40% higher risk of dying during the 19 years that researchers followed them, and a 51% higher risk of a cardiovascular-related death.
The study also found that women who were getting excess calcium had nearly double the deaths from ischemic heart disease (in which the heart gets insufficient blood) compared to women who took in 600 to 999 mg of calcium a day. And women who took supplements had even higher mortality rates.
So, Are Supplements Really Dangerous?
Some studies suggest that supplements may contribute to calcium deposits that harden and clog arteries. But a just-published analysis of data from the Women’s Health Initiative (a randomized clinical trial among more than 36,000 postmenopausal US women) found “little support” for links between calcium and cardiovascular risk.
“Recent studies on calcium have produced confusion among women and men. The cardiac events are not proven, just ‘associated’ with extra calcium,” notes Ethel S. Siris, MD, director of the Toni Stabile Osteoporosis Center at Columbia University Medical Center. “The key word here is ‘extra.’ We advise women to get ‘enough’ calcium.”
“The benefits of 1,200 mg of calcium are clear from a bone health perspective and to maintain calcium balance. Inadequate calcium sets up mechanisms that are bad for bone. More than 1,200 mg a day can cause kidney stones,” Dr. Siris points out.
How Much Is Too Much?
- The Institute of Medicine’s recommended daily allowance for women over age 50 is 1,200 mg of calcium a day (the advice is seconded by the National Osteoporosis Foundation).
- The Institute’s safe upper limit is 2,000 mg.
- To aid calcium absorption, you also need 500-600 International Units of vitamin D a day.
- It’s best to get calcium from your diet, but most of us only get around 300 mg a day from foods such as an 8-ounce glass of skim milk or a cup of yogurt. So taking supplements is reasonable, as long as you don’t overdo it.
- Bottom line: Read labels and keep track of how much calcium you get each day; ask your doctor if you need supplements.
As with most things, more is not always better.