Several weeks ago we reported on a fascinating article published in the British journal BMJ. It was a meta-analysis of 11 studies that included over 12,000 people over the age of 40. The investigators were trying to sort out the benefits and risks of calcium supplementation for the cardiovascular system. Some previous studies had suggested that high calcium intake from the diet was beneficial, but others showed that calcium supplements increased the risk for calcification of blood vessels.
The results of this evaluation created quite a controversy. People have been told for so long that calcium supplements are critical for good health that they have a hard time imagining there could be a downside. People also wanted more information. Here is just one example. We also encourage you to read the original research in the BMJ.
I appreciate these updates and do not expect an in-depth article, however, your reporting is pretty shallow and sometimes alarmist. There is nothing here to gauge the definition of how much is “too much” calcium. What is the specific age range? What dosage? How often?
Does culture make a difference i.e., British, American, Asian, Mediterranean diets and lifestyles are all very different. And what qualifies you to “suggest” getting calcium more from food (a “given” by the way) or to discontinue taking supplements which might be ill-advised for at-risk populations like older women!
I just don’t think medical “sound bites” are very valuable. I used to enjoy listening to your radio program, but I have come to see this website as more of a catalog to promote your products and less a source of serious and helpful health information.
The People’s Pharmacy Responds:
It is not surprising that so many visitors to this website would find our brief overview of the BMJ article disturbing. After all, Americans have been told for decades to take calcium to build strong bones. The trouble with that advice, however, was that it was not based on science.
If one really looks at the research, and there is an amazing amount of it, you will discover that the data demonstrating that calcium can be helpful in preventing fractures is exceptionally weak. Over the years more than 140 studies have examined the effects of calcium on fracture risk. About one third suggest benefit. Over half show no reduced risk (the rest were inconclusive).
What Do Epidemiological Studies Show?
Let’s take a look at epidemiology. In countries where people consume a LOT of milk, dairy products AND calcium supplements (Scandinavia, the United States and the UK), hip fractures are very common. In countries where milk and dairy consumption (and calcium pills) is low (Africa, China, New Guinea and Iran), hip fracture rate is much lower.
What about vitamin D? Many of the comments on this site have pointed out that the BMJ research was flawed because it did not include studies of vitamin D added to calcium. The meta-analysis could only analyze the studies that were available. Most of the big studies were done with calcium alone. The doses of calcium that were employed in the various studies ranged from 500 mg of calcium carbonate to 1,400 mg of calcium citrate and 2,000 mg of lactogluconate-carbonate.
As for vitamin D, of the nearly 40 studies that have been published involving both calcium and vitamin D combined, roughly half showed fracture reduction and half demonstrated no benefit.
Unless there is a clear benefit from something, we are unwilling to accept a risk. Although the risk of heart attack may seem small in absolute numbers, if tens of millions of women are swallowing large doses of calcium, the number of people who may be vulnerable is actually quite substantial.
We encourage visitors to actually read the BMJ article. It is free and very comprehensive. It is also understandable.
You may also wish to listen to our radio shows: we discussed the pros and cons of calcium supplements with Amy Lanou, PhD, co-author of Building Bone Vitality.
We have also discussed the calcium conundrum with Michael Castleman, author of Building Bone Vitality and Water Willett, MD, DrPH, Chair of Nutrition at Harvard School of Public Health. There is an mp3 of the show available.