Hot Topics: An Update on Calcium and Heart Health
The controversy continues on whether or not calcium supplements adversely affect cardiovascular health.
Are Calcium Supplements Safe?
A new study published in the Journal of the American Heart Association (October 2016) suggests a correlation between calcium supplements and arterial plaque formation, which may contribute to increased risk of heart attack. Speculation about this particular topic has been around for decades, since calcification is part of the atherosclerotic process.
This new study, entitled “Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10-Year Follow-up of the Multi-Ethnic Study of Atherosclerosis (MESA)”, is the latest contribution to a nearly decade-long debate about whether calcium supplements do more harm than good. The study found that people who used calcium supplements showed a 22% increased likelihood of developing heart disease over the decade.1
But get this: The research also finds that those who consumed the highest levels of calcium—from both foods and supplements—were 27% less likely to develop heart disease! The study reached that conclusion by comparing the 20% of participants with the highest calcium intake from both diet and supplements to the 20% with the lowest calcium intake.
The same day this study was published, the Council for Responsible Nutrition (CRN) issued the following statement by Duffy MacKay, ND, Senior Vice President, Scientific & Regulatory Affairs:
“This observational study demonstrated that people with the highest total calcium intake from both food and dietary supplements had the lowest risk of coronary artery calcification. This confirms the safety of calcium supplementation for heart health, which has been the conclusion of several large studies in recent years. Consumers should have confidence in the safety of calcium supplements, and women in particular should be aiming to get the targeted daily amount of calcium through a combination of diet and supplementation.” 2
How It All Started
This whole debate began with a study published in the British Medical Journal back in July 2010. The now famous meta-analysis, conducted by researchers in New Zealand, concluded that calcium supplements appeared to have only a minor beneficial effect on bone health and also suggested that supplements increase the risk of myocardial infarction by about 30% in people over the age of 40. They speculated the supplements might increase blood levels of calcium above normal, which could be dangerous to individuals at risk for heart attacks.3
After this study was published, news spread quickly through the medical community. Doctors began encouraging people to avoid calcium supplements and choose high calcium foods instead. While there is nothing wrong with this advice per se and in fact getting all the calcium we need from food is ideal, it’s also fairly difficult for many people on dairy free or vegan diets to meet the recommended dietary intake of calcium from diet alone and also difficult for women watching their calorie or fat intake. This leaves many women confused and concerned about how to adequately support their bone health, especially if they have high risk factors for osteoporosis or bone scans revealing osteoporotic changes.
Meanwhile, in spring of last year, The National Osteoporosis Foundation (NOF) and the American Society of Preventative Cardiology (ASPC) convened an Expert Panel to evaluate the effects of dietary and supplemental calcium on cardiovascular disease based on the existing peer-reviewed scientific literature as of May 1, 2016. The Expert Panel considered the findings provided by an independent Evidence Review Team at Tufts University and in July of 2016, the NOF and the ASPC determined that calcium in food or supplements does not adversely affect incidence of cardiovascular or cerebrovascular disease, disease-related mortality or all-cause mortality in most healthy adults. The Evidence Report and NOF and ASPC’s joint position statement was adopted by the board of directors of both societies on July 22, 2016, and published in the Annals of Internal Medicine at the end of October 2016, entitled “Lack of Evidence Linking Calcium With or Without Vitamin D Supplementation to Cardiovascular Disease in Generally Healthy Adults: A Clinical Guideline From the National Osteoporosis Foundation and the American Society for Preventive Cardiology”.
The focus of the guideline is to provide health professionals with an evidence-based recommendation about the health risks and benefits of calcium intake from food or supplements on cardiovascular and cerebrovascular disease incidence and mortality. The guideline states,
“Calcium with or without vitamin D intake from food or supplements has no relationship (beneficial or harmful) with the risk for cardiovascular and cerebrovascular disease, mortality, or all-cause mortality in generally healthy adults at this time. In light of the evidence available to date, calcium intake from food and supplements that does not exceed the tolerable upper level of intake (defined by the National Academy of Medicine as 2000 to 2500 mg/day) should be considered safe from a cardiovascular standpoint. Obtaining calcium from food sources is preferred. Supplemental calcium can be safely used to correct any shortfalls in intake. Discontinuation of supplemental calcium for safety reasons is not necessary and may be harmful to bone health when intake from food is suboptimal.” 4
The Bottom Line
In summary, there is actually one point on which all experts and researchers agree: obtaining calcium from food sources is preferred. Whether or how supplemental calcium can be safely used to correct insufficient intake is still being debated in the research world. But integrative practitioners know there is always the middle road of moderation and common sense we can follow when “science” can’t make up its mind. The average person in the U.S. consumes about 700 mg of calcium from food each day, leaving a shortfall of only 300-500 mg to meet the RDI for calcium depending on the age group. The sensible approach many clinicians have adopted is to recommend 300-500 mg of calcium in divided doses taken with meals, along with adequate vitamin D and vitamin K. As we well know, there is no one right answer for everybody. There’s a different answer for each individual depending on their eating habits and their lifestyle. But the healing arts are about applying our knowledge, our training, our experience and our understanding of human physiology and then trusting in the wisdom of nature to handle the details.
By Lisa Murray, RDN, LD
- John J.B. Anderson et al. Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10-Year Follow-up of the Multi-Ethnic Study of Atherosclerosis (MESA). Journal of the American Heart Association. 11 Oct 2016. http://dx.doi.org/10.1161/JAHA.116.003815.
- Mark J Bolland et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ 2010;341:c3691.
- Stephen L. Kopecky, MD; Douglas C. Bauer, MD et al. Lack of Evidence Linking Calcium With or Without Vitamin D Supplementation to Cardiovascular Disease in Generally Healthy Adults: A Clinical Guideline From the National Osteoporosis Foundation and the American Society for Preventive Cardiology. The Annals of Internal Medicine. 25 Oct 2016. http://www.annals.org/. Accessed 11.30.2016.