Calcium Conundrum

By Liz Robins / September 7, 2011

Every once in a while, new research findings seem to fly in the face of conventional nutrition wisdom, leaving health-conscious consumers scratching their heads or throwing up their hands. One of the most recent examples was a study published last July in the British Medical Journal that linked calcium supplementation with increased heart-attack risk.

Researchers analyzed 14 research trials in which subjects took either a placebo or at least 500 mg per day of supplemental calcium in studies lasting longer than a year, with a mean participant age greater than 40 years old. At follow-up a few years later, significantly more participants taking calcium supplements have had heart attacks than those taking placebo. The study authors concluded that calcium supplements (not taken with vitamin D) are associated with an increased risk of heart attack.

In light of the findings, consumers who’ve made a habit of taking supplemental calcium—around 43 percent of the U.S. population and nearly 70 percent of older women, according to findings published in the Journal of Nutrition—have been left to wonder: Do the potential risks of supplementation outweigh the mineral’s bone-supportive benefits?

“I think this is another example of a nutrient given alone and chronic-disease risk,” says American Dietetic Association spokesperson Roberta Anding, MS, RD/LD, CSSD, CDE. “The real key is that the calcium was taken without the needed vitamin D. There is research suggesting that when calcium is paired with vitamin D, there’s a reduction in the risk of heart disease.”

In addition to potentially counteracting increased risk associated with supplemental calcium alone, vitamin D plays a vital role in bone and overall health. It aids in calcium absorption, helps form and maintain strong bones and may protect against osteoporosis. This vitamin has also shown promise in staving off high blood pressure, diabetes and other chronic diseases. And, Anding asserts, there’s solid evidence that calcium and vitamin D taken together help prevent bone fractures. Recent research has even shown that improving calcium and vitamin D status substantially reduces all cancer risk in post-menopausal women—yet another motivation to aim for adequate amounts of both nutrients.

“My recommendation is to use nutrient-rich and balanced food, such as skim milk and yogurt, as your natural sources of calcium and vitamin D,” says Anding. Other calcium-rich foods include leafy greens, sardines in oil, tofu made with calcium sulfate and enriched forms of orange juice, soy milk and cereals. Substantial sources of vitamin D include some types of fish, cod liver oil and fortified foods such as milk, cereals and juices. (Adequate intake is especially important for people with limited sun exposure, as UV-B rays stimulate the body’s own synthesis of vitamin D.)

“If you don’t like these foods, try a supplement intended for bone health that is a combination of calcium (1000–1300 mg) and vitamin D (1000 IU, or International Units), along with vitamin K to provide the balance of nutrients needed for bone health,” says Anding. Look for citrate or malate forms of calcium, as those are the best-absorbed forms, and seek out the D3 form of vitamin D.

Before you head to the health-food store, read labels to take stock of how much calcium and vitamin D you’re already getting through food and drink. According to a report released last November (“Dietary Reference Intakes for Calcium and Vitamin D”), you may not be lacking as much as you think, if at all. (A simple blood test can help determine levels of vitamin D in the body, including that produced in response to sunlight.) Above all, says Anding, keep in mind that maintaining bone health isn’t as simple as just a pair of nutrients.

“It’s like trying to solve a jigsaw puzzle with two pieces,” she explains. “Consider the lifestyle approach and include calcium, vitamin D, vitamin K and magnesium. Avoid excessive amounts of protein, and follow a sound exercise program. Think overall nutrition and not just nutrients.”

Liz Robins
Liz Robins

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