 Calcium Supplements Linked to Increased Heart Attack Risk in Post-Menopausal Women
Millions of post menopausal women are using calcium supplements to protect them against osteoporosis. Are these supplements helping them or increasing their risk of heart disease. This is the focus of a recent study performed at the University of Auckland in New Zealand. The study evaluated data from the 2001 Women's Health Initiative Calcium/Vitamin D Supplementation Study, a seven-year trial watching over 36,282 postmenopausal women. Dr. Ian Reid and colleagues concluded from this data that women who took calcium supplements had a risk between 13 and 22 percent greater chance of having a heart attack than women who did not use calcium supplements. According to Dr. Reid, a woman’s risk went up regardless of whether the women also took vitamin D, which promotes calcium absorption and bone mineralization, or not. The group also found a milder increase in the risk of having a stroke among women taking calcium supplements.
Reid and colleagues wrote in their report in their 2011 article published in the British Medical Journal, "When these results are taken together with the results of other clinical trials of calcium supplements, with or without vitamin D, they strongly suggest that calcium supplements modestly increase the risk of cardiovascular events, particularly myocardial infarction. This data justifies a reassessment of the use of calcium supplements in older people."
One point also made in the article is that when old data is reviewed and compared to these new observations, there is a conflict with earlier reports from the Women's Health Initiative (WHI).
"In other WHI analyses, we found no association between [calcium and vitamin D] supplementation and [coronary heart disease] or stroke death and neither did these authors," said Andrea LaCroix, a professor of epidemiology at the Fred Hutchinson Cancer Research Center and a co-author of the earlier WHI studies.
LaCroix says "exploratory" reviews of past studies can often lead to findings that result from chance alone. But Reid and colleagues argue that the heart attack risk went unnoticed in earlier investigations because so many study subjects were taking calcium supplements outside of the study.
Calcium Supplements Linked to Heart Attack Risk
In a smaller study of post-menopausal women in New Zealand, Reid and his colleagues demonstrated that calcium supplements taken without vitamin D boost heart attack risk in post-menopausal women between 27-to-30 percent. The new data broadens the picture and includes women who take calcium and vitamin D -- a supplement combo that's steadily gaining in popularity, according to the Centers for Disease Control and Prevention's National Center for Health Statistics.
"Vitamin D and calcium [supplements] are the flavors of the month and it's the impulsive nature of our society to get that quick fix instead of getting back to eating whole foods," said Dr. Stephen Cook, an internist at the University of Rochester Medical Center in New York.
More than half of American adults take at least one dietary supplement, according to the CDC report.
Many experts now argue that eating a well-balanced diet makes supplements, which escape regulation by the U.S. Food and Drug Administration, unnecessary. Dairy foods are a good source of calcium, as are dark, leafy greens like spinach. And some cereals, juices and soy milk brands are also enriched with calcium.
When studies look at calcium intake obtained through the diet alone, without supplements, there was no indication of any increased risk to the women. We can now suggest that it may be safer to obtain all calcium through ones diet, and unless otherwise necessary, only take calcium supplementation when dietary calcium is inadequate or the woman is unable to obtain sufficient calcium through her diet.
Editors Comment
When a woman’s risk of osteoporosis is significant and her risk of heart attack is low, one might risk using calcium supplements to obtain their needs. There are however a number of other important issues that were not address in this study and were not even considered by the WHI program. One of the most important factors is the concurrent use of magnesium.
Magnesium acts to forces calcium into the bones hence lowering blood levels of calcium and increasing the value of calcium in protecting against osteoporosis. Magnesium, on its own, also reduce the risk of heart attack and stroke. Since the WHI study and the information above did not even consider looking at or evaluating the benefits of magnesium in this issue, we cannot know from their work determine what benefits might be attributed to magnesium and calcium supplements verses magnesium and calcium only through the diet.
High dietary calcium can and does increase the risk of coronary artery disease when magnesium is not present in sufficient amounts in the diet or supplementally, as calcium is unable to get into the bone to reduce osteoporosis so that it deposits in the tissues increasing the risk of osteoporosis, bone spurs, kidney and gall stones and even worse hardening of the arteries as it combines with cholesterol soft plaque to form hard plaque which narrows arteries and reduces circulation to the heart and brain and kidneys.
We recommend taking between 600 and 1,000 mg of magnesium along with calcium supplements and we always suggest if possible, get as much calcium as you can from your diet.
We also recommend vitamin D, 5000 IU daily in supplement form it helps to reduce the risk of osteoporosis as well as reducing the risk of cancer and other health problems.
Allen Lawrence, M.D.
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