Do calcium supplements increase the risk of cardiovascular disease?

Long-term supplementation with calcium may modestly increase the risk of heart attacks and strokes, suggests a new study.

The new meta-analysis included data from 28,072 participants of 13 randomized controlled trials evaluating the intake of calcium supplements alone or in combination with vitamin D (1g calcium and 400 IU vitamin D daily) over a long time period in connection with the risk of cardiovascular events (1). The analysis results indicate that the increased intakes may modestly elevate the risk of myocardial infarction and stroke, suggesting an unfavorable risk-to-benefit profile when comparing the benefits of calcium on fracture prevention with the risk of cardiovascular events: treating 1,000 patients with calcium or calcium plus
vitamin D for five years would cause an additional six myocardial infarctions or strokes and prevent only three fractures. The researchers speculate that increased serum calcium concentration due to long term treatment with supplements could increase the risk of vascular calcification.

Experts criticized that the meta-analysis’ methods, saying that they are flawed and point to many more studies touting the beneficial effects of calcium in bone health. As there is not enough evidence to confirm the association between calcium supplements and cardiovascular risk, further studies would need to be carried out to determine potential negative effects.

1. Bolland M. J. et al. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis. BMJ. 2011; 342:d2040.