Understanding Research on Calcium Supplements

WRITTEN BY Quinn Hand, BHSc, ND- 24 May 2012

Webber Naturals expert, Dr. Quinn Hand, ND addresses a recent study on calcium and heart disease.

Recently, CBC news discussed a recent study that claims calcium supplement use may raise heart attack risk, so we went to our experts to get their opinion. Here is what Dr. Quinn Hand, ND had to say:

First and foremost this study demonstrated an association between calcium and heart attack not a cause and effect relationship.
The greater heart attack (myocardial infarction – MI) risk was seen in people who use calcium only supplements (meaning they were using calcium alone and not in the presence of other nutrients). In those people who used calcium plus other supplements (like multi-vitamins), there was a statistically significant but smaller association. Furthermore, they observed that a more recent intake of calcium supplements, not a cumulative intake of calcium supplements over time was associated with increased heart attacks. So, longer-term use may be beneficial (still to be determined in future research).

Please take note that most recommendations from MDs are to take a certain dose of calcium alone (or with Vitamin D only) and little knowledge exists about the need for other trace minerals being present in order to facilitate absorption. Naturopathically, we tend to always recommend calcium in conjunction with Magnesium and Vitamin D, at a minimum. It is usually wise to ensure other nutrients are present such as Vitamin A, Vitamin K boron, zinc, vanadium, omega-3s, etc. Of course, we also want to ensure people are eating whole diets where many of these nutrients are found, such that the trace elements can ensure calcium ends up where it should. What we really need is a study of calcium in more bioavailable forms, in conjunction with the nutrients that help its absorption.
In order to gather data on the dietary intake of calcium and supplements, most of these studies use questionnaires that require people to remember the previous 12 months or longer. This always poses a problem in studies as there is the risk of recall bias – meaning people forget what they have consumed, either under-reporting or over-reporting their intakes.

Additionally, this was a single evaluation at the start of the study, which means they were not able to account for dietary changes over the long-term of the study.
Based on the fact that this data was self-reported via questionnaire, the researchers could not fully determine the dose and type of calcium people used. This is a critical piece of data, as lower doses or certain types of calcium that are more easily absorbed may confer no risk or benefit.
Compared with non-users, users of calcium supplements tended to be female, more physically active and less likely to be overweight. However, they also tended to be older, with lower education (known to be a determinant of health status) and had a longer history of smoking – a clearly demonstrated risk for MI.
There was no association between calcium supplements and stroke risk or overall CVD mortality – it is hard to entirely determine why this is, but it may be attributable to the fact that calcium has the ability to lower blood pressure.

So, the take home message is that calcium should not be supplemented alone and that while these studies are important, adding to the research base, we still don’t have enough data to conclude one way or the other. I suggest taking dietary calcium from all sources, not just dairy, plus using more bioavailable forms of calcium such as citrate or hydroxyapatite in conjunction with other trace elements. We need to remember that osteoporosis is more prevalent in North America, and this may reflect the fact that we have an unhealthier diet that can cause greater acidity in the body, thus leaching calcium from the bones to neutralize a more acidic environment. So, we need to start at the ground level, improving diet and using supplements judiciously in order to help prevent further complications.