Calcium Safety and Cardiovascular Disease Clarified with Guidelines Offered
Reviewed by: Tori Hudson, ND
Author: Chang M, et al.
Reference: Calcium intake and cardiovascular disease risk: An updated systematic review and meta-analysis. Ann Intern Med 2016; Oct 25 (epub)
In the last 6 years, there have been published trials raising concerns regarding calcium supplementation and excess risk for myocardial infarction and stroke, although the findings have not been consistent. An updated systematic review and meta-analysis of evidence on the effects of calcium intake from diet and from supplements, either alone or with vitamin D on the risk for cardiovascular disease in generally healthy adults, was conducted. There were four randomized trials and 27 observational studies that were analyzed. Calcium supplementation ranged from 400 mg/day to 1,600 mg/day.
The key points of the analysis were the following:
- Calcium intake with or without vitamin D, and either from food or supplements had no helpful or harmful risk for cardiovascular events in healthy adults.
- Calcium from either food or supplements, that does not exceed the “tolerable upper level of intake” is safe in relationship to cardiovascular health
- These conclusions were primarily from observational studies. The two previously published meta-analyses that showed some excess risk in randomized trials were considered unreliable by the current authors and reviewers.
- Dietary sources of calcium may be preferred over supplements because it is easier to avoid an excess. Excess calcium may cause gastrointestinal side effects, increase the risk for kidney stones and interfere with absorption of medications.
Commentary: This issue has been confusing the last several years. But for those consumers and providers who have understood the guidelines from the Institute of Medicine, of 1,000 mg-1,200 mg/day of calcium, and understood this number is a total of dietary and supplemental calcium, there was never reason to be concerned. Most adults in the U.S. have a dietary calcium intake of 500mg-1,000 mg/day. These then requires supplementing on average, an additional approximate 500 mg/day in pill form. It was never intended that we eat 1,000 mg/day and then take another 1,000 mg-1,200 mg/day. Don’t forget to look at the amount of calcium in all your dietary supplements, per the serving size on the label, and then determine what it is based on the number of pills you are actually taking. Estimating your daily dietary calcium intake can be done by looking at charts on food sources of calcium. A general guideline has been to count 250 mg/day for the non-dairy and non-soy foods and then allow 300 mg per serving of dairy or tofu or soy milk.