The conclusion is that while calcium supplements may pose an increased risk of heart disease, diets high in natural sources of calcium are heart-protective.
New research published in the October issue of the Journal of the American Heart Association suggests that dietary calcium in the form of supplements may cause harm to the heart and vascular system. The study analyzed data from 2,700 adults between the ages of 45 and 85 who participated in a U.S. government-funded heart disease study. CAT scans were done initially and again 10 years later to assess the presence of plaques containing calcium in the arteries.
The research showed that people in the top fifth category of calcium intake had a 27 percent lower risk of heart disease, compared to those in the bottom fifth. But, when the source of the calcium was separated out, the study found that people who took calcium supplements had a significant increase in plaque buildup in their arteries and higher odds of heart disease compared to those who did not take calcium supplements. People who took calcium pills were 22 percent more likely to have plaque buildup in their arteries. The conclusion is that while calcium supplements may pose an increased risk of heart disease, diets high in natural sources of calcium are heart-protective. Besides heart disease, other studies have suggested that calcium supplements increase the odds for kidney stones.
Why are calcium supplements harmful? The body apparently responds differently to the calcium found in supplements than it does to naturally occurring calcium. It may be that the body can't handle a large dose of calcium all at once. Or, the problem might be the type of calcium salts commonly used in supplements. Perhaps those taking supplements are just getting too much calcium, between multivitamins, supplements and calcium-fortified foods.
According to the National Institutes of Health, 43 percent of American adults take a supplement that includes calcium. More than half of women older than 60 take a calcium supplement to help decrease their risk of osteoporosis. Many people take supplements as "insurance" against a bad diet.
Because supplements are purchased over-the-counter, most people assume they are safe. We tend to have an "if a little is good, more is better" mentality that shouldn't apply to supplements. It's important to know that over-the-counter supplements, including vitamins, minerals, herbal remedies, diet pills and so on, do not have to be approved by the Food and Drug Administration. There is no regulation to assure that the quality is good, the dosing is consistent or that the claims are factual. You should always talk to your health care provider before adding any supplement to your diet. Certain vitamin, mineral or herbal supplements can interact with medications you may be taking. Even if you do not take any prescription meds, you should check with a health care provider to see if you actually need to take a supplement or if there are other ways you can get nutrients you may be lacking.
Many foods — including fruit juices, cereals, energy bars and even water — are now fortified with vitamins and minerals. Is this good or bad? Since the vitamins or minerals in these are not naturally occurring, they likely act more like a supplement in your body. The amounts in food may be inconsistent, and they may vary in bioavailability, or how well the body can use or absorb the vitamins. It is quite possible to get more than the recommended daily amount of some vitamins and minerals if you consume fortified foods and take a multivitamin.
How much calcium do you need? For men 51 and older, the recommendation is 1,000 milligrams daily. For women 51 and older, it is 1,200 milligrams daily. Milk is the first thing to come to mind when we think about calcium, but calcium has many natural sources, including the following:
Plain low-fat yogurt, 8 oz – 415 mg
1 cup skim milk – 306 mg
1 cup 1% cottage cheese – 138 mg
1.5 oz cheddar cheese – 307 mg
1/2 cup tofu – 434 mg
3 oz canned salmon – 181 mg
23 almonds – 75 mg
1 cup raw kale – 101 mg
1/2 cup dry figs – 121 mg
1 orange – 74 mg
This study on calcium and heart disease confirms what I have long believed: It's always better to get your nutrients from whole food than from a pill.
Anita Marlay, R.D., L.D., is a dietitian in the Cardiopulmonary Rehab department at Lake Regional Health System in Osage Beach, Mo.