While the verdict is still out on whether or not calcium supplements support bone health, new research in JAHA suggests they’re not good for your heart.
- Many elderly patients take calcium to try and treat or prevent osteoporosis as they age, though research suggests calcium intake doesn’t always offset this risk.
- Earlier research suggests that healthy adults with high levels of dietary calcium (not supplements) have a lower 10-year risk of ASCVD.
Since there’s little known about the effects of calcium supplements on the heart, researchers performed an observational analysis of EHR data from 237k patients in Hong Kong, 16% of which were prescribed calcium supplements.
After matching them to controls researchers found that patients on calcium supplements had higher CV risks across the board including:
- Acute MI risk: +10%
- Stroke: +6%
- Coronary heart disease: +9%
- CVD hospitalization or ED visit: +16%
Notably, the risk increases were higher in men and when patients didn’t take vitamin D supplements alongside calcium.
- Patients taking calcium without vitamin D saw a 21% increase in composite CV risk, while those taking both actually saw a 3% decrease in risk.
So where do these results come from? The researchers suggest it could be because circulating calcium levels directly contribute to aortic and coronary artery calcification.
- For example, calcium supplements can lead to an instantaneous increase in serum calcium levels for >6 hours.
- Population‐based studies have also alluded to a link between calcium supplementation and vascular calcification.
However, it’s important to remember that this retrospective study is the first of its kind and is purely observational, so it can’t prove causation or that calcium supplementation is a CV risk factor.
- It’s unlikely that a comparative study would ever be conducted either.
- And the study is on a mostly homogenous Asian population since it comes from Hong Kong.
The Takeaway
Calcium supplementation is common, especially in older patients, many of whom already struggle with CVD risk factors or co-morbidities. While this observational study is limited in what it can prove, it’s a good reminder to clinicians that more isn’t always better when it comes to supplements.
