Calcium supplements safe for heart health: Harvard study

27-Nov-2012 - Last updated on 27-Nov-2012 at 15:37 GMT

Supplements of calcium do not increase the risk of arterial hardening, says a new study that used state-of-the-art CT scans of over 1,200 men and women.

Data from the Framingham Offspring Study indicated that there was no link between calcium supplements and an increased risk of artery calcification, according to data published in the American Journal of Clinical Nutrition.

There have been some studies that have reported that calcium supplements taken to reduce the risk of osteoporosis may cause cardiovascular problems, but a recent report from the Institute of Medicine concluded that “evidence from clinical trials currently does not support an effect of calcium intake on risk of cardiovascular disease”, explained researchers led by Elizabeth Samelson from Harvard Medical School.

The new study supports the safety of the mineral, and found that both dietary and supplementary sources of calcium had no effect on scores of coronary artery calcification.

Study details

Samelson and her co-workers analyzed data from 690 women and 588 men with a mean age of 60. Intakes of dietary and supplemental calcium were assessed using food-frequency questionnaires and arterial calcification was measured using CT scans.

Results showed that scores of coronary artery–calcification actually decreased with increasing total calcium intake, but the trend was not significant after adjustment for a range of other factors, including age, BMI and other lifestyle factors.

“Our prospective study in a large, community-based population of women and men evaluated the relation between calcium intake, with an upper range as high as 3000 mg/d, on a specific measure of the presence and severity of coronary atherosclerosis (ie, coronary artery calcification), which is an independent predictor of cardiovascular events,” wrote the researchers.

“We used state-of-the-art CT measures of coronary artery calcification, and we were able to take into account important factors in a study of calcium intake and vascular calcification such as vitamin D intake, prevalent coronary artery disease, and kidney function.

“Our results do not support a significant detrimental effect of calcium intake on coronary artery calcification,” they concluded.

Source: American Journal of Clinical Nutrition
December 2012, Volume 96, Pages 1274-1280, doi:10.3945/ajcn.112.044230
“Calcium intake is not associated with increased coronary artery calcification: the Framingham Study”
Authors: E.J. Samelson, S.L. Booth, C.S. Fox, K.L. Tucker, T.J. Wang, U. Hoffmann, L.A. Cupples, C.J. O'Donnell, D.P. Kiel

2 comments

Doubt

Posted by Jim, 07 December 2012 - 03:54 GMT

Craig,

as an end user of products such as flour infused with calcium, is it proper to assume its ineffectiveness.
From your findings, how does one typical consumer know that calcium enriched products is making a difference in their health?

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Methodologically flawed

Posted by Craig McIntosh, 30 November 2012 - 22:29 GMT

This is pretty disappointing - especially coming out of Harvard.

While the full paper acknowledges a few of the potential issues:-

•“It is possible that calcium intake, particularly from supplements, was too low in participants to detect a potential effect” and that
• “the highest quartile of total energy-adjusted calcium intake in our study on vascular calcification could have been obscured by an inadequate control of confounders” and that
• “The assessment of diet is subject to error such that a non-differential misclassiifcation could have diluted an association between calcium intake and vascular calcification”

They failed to mention the significant drop off in participants returning at the four year mark for the scans – obviously anyone who had died or was to infirmed to return was excluded from the scans/results. This has already been identified as a methodological flaw and quite frankly makes the paper worthless in light of the wealth of RCT information out there.

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