What are the Risks of Taking Calcium Supplements?

Feb 04, 2013
Calcium Supplementation

Calcium Supplementation and ME/CFS, FM or ES

This literature review was spurred by an email from Dr. Paul Cheney who sent similar information to his patients. Note that the issue of nutritional supplementation is not unique to people with ME/CFS, FM or ES, it is a public health issue. Patients with ME/CFS, FM and ES tend to be high users of nutritional products so this will be relevant to you.

Calcium Supplements Side Effects and Risks

The majority of persons in western countries over the age of 50 take calcium supplements on medical and public health advice to decrease their risk of osteoporosis (thin bones) and bone fractures. The public has not been informed that there could be adverse effects from calcium supplementation. As you know I believe that every intervention that has the power to help has the power to hurt. Informed consent (knowing the risks and benefits) is key.

I have noticed that many of my patients take enough supplements to push their total daily calcium intake above the recommended daily allowance. The Health Canada recommendations are to take 1000mg/day for men and 1200 mg/day for women. Overuse may occur because it is difficult to calculate daily nutritional intake and therefore most people don’t know if they are getting enough in their diet or if they need supplements. They err on what they consider the side of caution by taking more (caution with regards to bone health).

The Latest Research on Calcium Supplements

Many of you know that I have been discussing for some time that taking too much calcium supplementation may be harmful. The reason for this is that calcium is part of the inflammatory cascade that leads to heart disease and stroke. The cholesterol plaques that form in arteries become hard and more harmful when calcium is deposited in them. There is an increasing number of studies suggesting that when it comes to calcium more is not better. I will review here three recent, large, prospective studies which show that taking either too little or too much calcium may increase the risk of a heart attack.

Like all other issues to do with the body, this one is complicated and there are as of yet no clear guidelines coming from the literature. As an example of the complexity, calcium can be taken in many ways and contexts including:

  • as part of a healthy diet (my preference is always for real food over supplements)
  • added to a healthy diet in the form of dairy products or other calcium-rich foods
  • added to a healthy diet in the form of supplementation of calcium alone
  • added in the form of supplementation of calcium with vitamin D and magnesium with other bone supporting minerals
  • added as part of a multi-mineral supplement
  • added to a non-healthy diet in any of the above forms.

A prospective German study of 23,980 male and female participants between the ages of 35 – 64 years showed that:

  • Those taking more calcium in their regular diet (regular dietary + dairy) had a lower risk of heart attack than those with lower dietary intake --- dietary calcium is good for the heart.
  • Overall, calcium intake in any form did not change the risk of stroke or death from cardiovascular disease.
  • Users of calcium supplements had a 2 -3 X greater risk of heart attack than the non-supplement users --- calcium supplements may not be as good as dietary calcium.

A 12-year prospective study of 388,299 men and women in the US aged 50 – 71 years as part of the National Institutes of Health AARP Diet and Health Study. They found that:

  • Men but not women who used calcium supplements had a higher risk of cardiovascular death specifically from heart disease but not from stroke ---men and women may respond differently to calcium.
  • Dietary calcium was not associated with cardiovascular disease in either men or women --- dietary calcium is safe.

 A 16-year Swedish study prospectively followed 61,433 women born from 1914 – 1948. They reported that:

  • Women with a total calcium intake (from diet plus supplements) above 1400 mg/day had higher death rates from all causes compared with those who took 600 mg – 1000 mg/day --- too much calcium could be bad.
  • The high calcium users had higher rates of cardiovascular disease but not stroke.
  • Overall taking calcium supplements (eg. 500 mg tablets) was not associated with death but among supplement users, with the highest calcium intake (ie above 1400 mg/day) there was a 2.7 X risk of death by all causes --- calcium supplements may be harmful if intake is too high.

The take-home message from this is that just because an intervention “makes sense” and helps one problem (in this case bone health) it does not mean that it is safe overall. So what to do?

The Best Calcium Supplement is Through Diet

As I advise in my manual “Let Your Light Shine Through”, the best diet is the “real food diet”. This means getting as much nutrition as possible from real, homemade, non-processed food, organic if possible. The studies above suggest that the ideal calcium intake with regard to heart health is between 600 – 1000 mg/day. Supplements should only be used if one cannot obtain this much calcium through the diet. The bottom line, more is not always better.

How does One Calculate How Much Calcium is in the Current Diet? 

The use of the diet charting tool or a similar tool or apps is invaluable. I discuss the use of this tool in Session #5 of my manual. By charting your intake for 7 – 10 days you will be able to accurately establish your current intake of all the major nutrients including vitamins, minerals, amino acids and fatty acids. If your intake of calcium or other nutrients is deficient the tool can suggest foods you can add to your diet to increase intake to a preferred range. If your intake is sufficient, no further action needs to be taken.

Author: Eleanor (Ellie) Stein MD FRCP(C)

I am a psychiatrist with a small private practice in Calgary and am an assistant clinical professor in the faculty of medicine at the University of Calgary. Since 2000, I have worked with over 1000 patients, all with ME/CFS, FM and ES. My passion for this field comes from my own struggle with these diseases, my desire to improve my health and then pass on what I learn. My goal is for every patient in Canada to have access to respectful, effective health care within the publicly funded system. 


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