Calcium and Heart Attacks
Recent publicity in the media on the danger of calcium supplementation increasing the likelihood of a heart attack or stroke has confused many consumers. Especially in USA where 51% of the population over 19 years of age take calcium supplements, with 66% of women over 60 taking calcium supplements (National Health and Nutrition Surveys USA).
This publicity has arisen from a series of meta analyses carried out by Prof Ian Reid at the Auckland Medical School in NZ, the results being published in the British Medical Journal in early 2011. For these meta analyses he has chosen a wide range of trials covering some 29,000 people and states for every 1,000 people taking calcium supplements we save 3 fractures and cause 6 heart attacks.
While he is not sure of the reason, he postulates that when a consumer starts taking a conventional calcium supplement it causes an abrupt spike in the blood serum calcium and this causes the increased risk. His recommendation is to take any calcium supplementation in the form of food rather than a capsule. That is increase the intake of such high calcium foods such as dairy products. If you must take a supplement take one that is very insoluble, take it with food and split your daily dose rate.
Prof Reid’s views are challenged by a number of people. The Council for Responsible Nutrition (CRN), the Woman’s Health Initiative (WHI), a number of the health supplement organisations and a number of well known heart specialists. All express concern at the figures and say that Prof Reid has just selected trials that proved his thesis and left out those that did not fit and they say he poses more questions than answers. There are many more trials that show no heart effects than the ones he has selected and none of the trials were designed to measure effects on the heart
That may be correct, and mega analyses can often give strange results. For example a world meta analyses of dairy product consumption and osteoporosis rates show clearly an inverse ratio. Generally countries with a high dairy product consumption have much higher rates of osteoporosis than those with a low dairy product consumption. Still Prof Reid is a very reputable researcher and I am sure he honestly believes in his theory. It would seem foolish not to keep this matter under review and in the meantime follow Prof Reid’s advice if taking supplements (generally he prefers calcium to be taken in the diet in a natural form with other minerals and nutrients).
However he says if you do need a calcium supplement make your choice an insoluble one, preferably a complex one that contains a range of minerals and proteins and is akin to a concentrated food.Take them with meals and split the daily dose.