Not too long ago, calcium was the least controversial dietary supplement. Millions of people take calcium, hoping to keep their aging bones strong and prevent osteoporosis-related fractures, which half of all women eventually experience, as do many older men. The main debates were about which form of calcium is best, whether the pills could cause kidney stones and what other nutrients, if any, the supplements should also contain.
However, recent news has probably made many people wonder if they should stop taking the pills. First, some studies have linked calcium pills to increased risk of heart disease. And the influential U.S. Preventive Services Task Force dropped a bombshell when its draft recommendations concluded that standard doses of supplemental calcium and vitamin D don’t prevent fractures in postmenopausal women.
Here’s what you need to know.
Calcium is vital for bone health. Bones are living, active tissue. They constantly absorb and release calcium and other minerals, depending on many factors, such as hormones, exercise, genetics and overall diet. From childhood through early adulthood, bones grow in length and width, but then, in middle adulthood, the rate of bone loss exceeds that at which it is made.
In its 2010 guidelines on calcium, which relate primarily to bone health, the Institute of Medicine (IOM) set the recommended dietary allowance (RDA) for women over 50 at 1,200 milligrams a day from food (preferably) and supplements, and for other adults at 1,000 milligrams. However, research suggests that 800 milligrams a day is enough for many healthy people, particularly those with adequate vitamin D intake and a diet rich in produce and whole grains.
It’s better to get calcium from food than supplements because foods naturally rich in calcium supply many nutrients important for bones and general health. Dairy foods are the leading sources of calcium, though many people have trouble digesting the lactose (milk sugar) in them. Fish with bones, such as sardines and canned salmon, as well as dark leafy greens and most tofu, contain good amounts. And there are lots of calcium-fortified products. However, many people don’t eat calcium-rich foods often, which is why supplements have been recommended to make up for the shortfall.
How much is too much?
High doses of calcium supplements (especially when taken without food) are known to increase the risk of certain kinds of kidney stones. In contrast, foods naturally rich in calcium (notably dairy products) seem to protect against kidney stones.