The Other I

November 15, 2011

Supplements are not substitutes

Filed under: Osteoporosis — theotheri @ 10:19 pm

Last week, a reader asked if I was familiar with the recent research report finding that calcium supplements seem to be associated with a higher incidence of heart attacks than were those who don’t take calcium supplements.  I promised to review the research if I could.  Which I have just done.

As I suspected, the results are far from conclusive.  They may even be an illusion, a statistical significance that occurred by chance as a result of amalgamating and re-analyzing a large number of different research studies into the effects of calcium supplements.

Although the results should be looked at seriously, there are several reasons why many doctors are not convinced.  The first is that it is strange indeed that the calcium-supplement group should suffer a greater number of heart attacks but show no greater mortality rates than the non-calcium group.  Heart attacks kill a significant percentage of people whom they strike.  Why, then, doesn’t this show up in more deaths among the calcium-supplement takers?

Equally perplexing is the fact that although the calcium group seems to show an increased incidence of heart attack they are not more prone to stroke or death from heart disease.

Another doubt arises from the fact that what we have at best is a correlation, not a demonstration of cause.  Even supposing that the calcium-takers do suffer higher rates of heart attacks, it is possible that a larger percentage of them were taking supplements on the recommendation of their doctors who had noted worrying bone density depletion.  So it is possible that reduced bone density and heart attacks were caused by many years of poor nutrition and/or little exercise, not that the calcium supplements caused the increased heart attacks.

Another possibility is that there are significant differences within the calcium-supplement group that explain the differences.  There is no analysis of the kinds of supplements people took or other life-style variables among them.

Calcium-rich foods are absorbed best because they are absorbed slowly. 

 Not all supplements are absorbed equally well.  Calcium absorption depends on the presence of other nutrients, so that supplements taken with vitamin D as well as vitamin K are absorbed better than calcium taken alone.  In any case, not more than 500 mg calcium can be absorbed at any given time by the body.  So the recommended doses of 1000 or 1200 mg/day must be spread out throughout the day to have any chance of being effective.  If they are not, the chances are indeed that they will be detrimental rather than helpful.

Not only does a correlation – if it exists – between calcium supplements of any kind and an increased incidence of heart attack not prove causation, supplements are not substitutes either.  But many people simply want to take a pill and forget about it.  They do not change their exercise or nutritional regimes.  They do not reduce caffeine, peanuts, or moderate alcohol intake.

There are no absolute answers.  We are all different, and scientific research does not offer us absolute answers.  In this case, above all, the research findings have suggested more questions than it has answered.

For myself, I’m continuing to take 250 mg calcium with vitamins D & K with each meal and before bed.  I also do 30 minutes serious exercise a day, and emphasize alkaline, calcium-rich foods.

We still have to live with uncertainty.   But I will say I’m grateful we don’t live in an age when doctors were convinced that leaching was the cure-all for almost everything that went wrong with us.






  1. Excellent analysis. So much of the flimflam that goes under the guise of statistical data passes as good science, especially in the popular media–the weekly causes/cures for cancer being one example; another being the constant barrage of propaganda to get constantly tested for every conceivable malady, though it’s a boon to the medical industry here in the US.


    Comment by pianomusicman — November 16, 2011 @ 3:05 pm | Reply

    • Thank you so much for your comment. We are absolutely on the same page. The medical system here in Britain has its weaknesses – not the least of which is a wide-spread disregard for the elderly. But it is a relief not to be bombarded with advice to take every test every devised to make sure I’m not suffering from something or other.

      On the other hand, it was my American GP who suggested – in the absence of any symptoms whatsoever – that I have a bone density test which revealed a worrying depletion of bone density. I did not take her advice to take bi-phosphonates, though. I suspect the exercise, supplement, and nutrition regime I began ten years ago has contributed significantly to the fact that I am still in quite good shape “for my age.”



      Comment by Terry Sissons — November 16, 2011 @ 3:45 pm | Reply

  2. Thanks again for all the information, Terry—and all the wonderful and thoughtful commentary. I will most certainly keep in touch.

    Stay healthy,
    Kathie K.


    Comment by Kathie K. — November 20, 2011 @ 8:17 am | Reply

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