Friday, February 15, 2013

Calcium and Heart Disease: What's The Story?

I don't know many doctors who would tell you that taking calcium supplement pills may be a bad thing.  Alas, I was one of them, but I think that's about to change big-time.

As far back as I can remember, women were told to take calcium supplements to prevent osteoporosis. It was practically a staple of childhood that we all needed to drink milk with calcium to develop strong bones. Apparently as we grow older this need increases, and ignoring the debate if dairy is even healthy, most doctors must believe that dairy is no longer a sufficient source of calcium because they recommend that women take 1,000 to 1,200 mg of extra calcium daily as supplements to keep their bones strong.

If you had asked me two years ago, I would have raised no objections to such advice.  Then a funny thing happened. (Not the "ha, ha" kind of funny, but the "that's odd" type.) I started noticing over the past couple of years a few studies that suggested that calcium supplements may actually do more harm than good. A study in New Zealand showed that even 500 mg a day of calcium increased the risk of heart attack by 30%.

Looking around, I kept expecting to hear something from other parts of the medical community warning about calcium and chastening doctors to weigh the risks and benefits before making further recommendations. But there was nothing. Nevertheless, I began to speak about it in my lectures sharing my new knowledge about the potential role of calcium supplements in the calcification of arteries and heart disease.  My audiences were stunned; I would literally hear gasps. How could a doctor be openly challenging the long held assumption that all post-menopausal women should take calcium supplements to prevent osteoporosis and not hear a peep of concern from their own doctors.  Obviously, I must be wrong.

The truth be told, sometimes I wonder if I misread or misunderstand the information I come across. For example, when the Institute of Medicine lowered the threshold for a Vitamin D deficiency from 30 ng/ml to 20 ng/ml, again I waited for the reactions from the medical community.  Again, zip.  So confused by the lack of reaction, I went back and reread it. There it was again clear as day. The threshold had definitively been lowered and like the line from poem, "not a creature was stirring, not even a mouse." There was nothing but dead silence.

Well I hope that's about to change. During the past week or so a flurry of studies has emerged which has put the issue on the national radar. The first study cautioned men about the role of calcium supplements in forming kidney stones and the second study warned about its role in heart disease. This week a new study about women came out that should have everyone talking.

Checking if calcium supplements raise the risk of dying from heart disease, Dr. Karl Michaelsson, a clinical professor in the department of orthopedic surgical sciences at Uppsala University in Sweden, analyzed data collected on more than 61,000 women enrolled in a study on mammograms. The study, published in the British Medical Journal, showed that over 19 years of follow-up, nearly 12,000 women died with the highest rates of death identified among women whose calcium intake was higher than 1,400 milligrams a day. Women who took less than 600 milligrams of calcium a day also were noted to have an increased risk of death.  (That makes sense since calcium is an essential mineral, which means you can't live without it.)

The Swedish study showed that death was ONLY increased among women whose calcium came partly or wholly from calcium supplements.  (Of course, a supplement industry representative weighed in immediately that the study was flawed because it was not specifically meant to address calcium supplements and heart disease. Who cares? Even though it was not a cause and effect study, didn't look at Vitamin D, and its initial research purpose was not to evaluate what calcium does to the heart, the study offers a pretty compelling argument that calcium supplements may be very dangerous.)

But don't take my word for it. Quoting from Medline, "Many older adults increase dietary intake of calcium or take calcium supplements to prevent bone loss and there had been speculation that increased calcium intake with or without vitamin D could improve cardiovascular health," said Dr. Gregg Fonarow, an American Heart Association spokesman who wasn't involved in the study.

However, a number of recent studies have suggested that higher dietary intake or calcium supplementation may not only not improve cardiovascular health -- they may be associated with increased risk for cardiovascular events and mortality, said Fonarow, a professor of cardiology at University of California, Los Angeles."

For over a year, I have been asking my audiences if their doctors adjust their calcium recommendation based on how much calcium they get from their diet. The answer has always been no. The key finding in the new study was that if women exceeded 1,400 mg of calcium a day based on a combination of food and supplements or supplements alone, the death risk doubled. No such risk was seen with food alone.

So the bottom line is everyone needs calcium and it is best and safest to get it from foods like broccoli, almonds, tofu, sardines, kale and other leafy vegetables, and almond milk. As I am not a fan of dairy, I don't recommend dairy products but Greek yogurt, etc. are also good sources of calcium. Avoid antacids with calcium, they are just as bad as calcium supplements.

It will be curious to see if doctors now change their calcium recommendations and actually take the time to adjust for diet. I give patients handouts with the concentration of calcium in healthy foods so they can make their own adjustments. As I like to say, to paraphrase Sy Syms the retailer, "an educated patient is my favorite type."

By the way, if you are interested in strong bones and a healthy body, there is no substitute for weight-bearing exercises.


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