Previous randomized trials suggested that calcium supplementation was associated with an increased risk for myocardial infarction (heart attack) and stroke. However, this finding has been inconsistent. To avoid further confusion, researchers conducted an updated systematic review and meta-analysis on the effects of calcium intake and heart disease.They looked at calcium from diet and supplements, both alone and with Vitamin D, on the risk for cardiovascular disease in generally healthy adults. Four randomized and 27 observational studies were analyzed. Supplemented daily calcium intake levels ranged from 400 mg to 1600 mg.
Here is what they found:
1. Calcium intake with or without vitamin D from food or supplements has no relation (good or bad) with risk for adverse cardiovascular (CV) events in healthy adults.
2. Calcium from food or supplements that does not exceed 2000-2500 mg daily is safe in regard to CV health.
3. The prior two published meta-analysis that showed excess cardiovascular (CV) risks in randomized trials were not designed primarily to examine CV outcomes. In other words, these studies measured coronary artery calcification (which can increase ones risk) vs the number of actual heart attacks or stroke.
4. Calcium food sources are still preferred over supplemental calcium.
The bottom line: Dietary and supplemental calcium intakes lower than 2500 mg daily does not increase excess risk for adverse CV events.
Reference: Moloo, J. Is calcium supplementation associated with higher cardiovascular risk? JWatch.org 2016 December Vol. 21 No. 12