Supplement Problems: Calcium

By AltMed1-Peggy  

(Original article posted May 25, 2011; updated information added on May 26, 2011.)

Yesterday we told you about the concerns that have recently been raised about vitamin E supplements. Today we take a look at the latest on calcium.


A new study published in the June 2012 issue of the journal Heart reported that taking high amounts of calcium supplements may increase risk of heart attack and stroke.

Previous research showed calcium was beneficial, especially post-menopausal women and others who are at risk of osteoporosis. Calcium supplements were also to help lower the risk of high blood pressure, type 2 diabetes, and obesity, heart attack, and stroke. No wonder many people say their physicians advised them to take a calcium supplement every day, and others decided on their own that taking calcium would be a good idea.

But now the new study raises serious questions about calcium. 

German researchers analyzed data collected over an 11-year period from 23,980 people aged 35 to 64 who did not have cardiovascular disease when they joined the study between 1994 and 1998.

Participants were asked to take a self-administered “food frequency” test that asked about their consumption of 148 foods over the preceding 12 months. They were also asked about supplement use during a baseline interview and then in periodic follow-up questionnaires.  Analysis of that data told the researchers how much calcium the participants were consuming and in which form (dietary calcium in foods and beverages or calcium supplements such as tablets and chewables).

Next they looked at the cardiovascular disease in the participants. Information obtained by surveying participants and survivors of those who had died was verified through medical and death records. After compensating for other confounding factors that could skew the results, they concluded that dietary calcium did not have a significant impact on heart health risks but calcium supplements actually increased risk of heart attack and stroke.

Why the difference? Calcium in food is consumed in smaller amounts scattered over the course of the day, which means that the calcium in food is absorbed more slowly, a press release about the research explains. Supplements, on the other hand, deliver a bigger dose of calcium all at once and that causes “calcium levels in the blood to soar above normal range.” The researchers think that spike of calcium or “flooding effect” is the key that explains why supplements can be harmful when dietary calcium is not.

The bottom line, the study authors say, is that calcium supplements should be used with caution and patients should be discouraged from taking calcium supplements.

Others who have read the study disagree, according to a report by NutraIngredients-USA. They point out the importance of calcium, especially for elderly people who are at risk of falls and fractures caused by weak bones. And, they note, this single study is not proof that calcium supplements do cause heart attacks, nor does it provide a strong enough reason to disregard the good things calcium can do. Until additional research confirms this study’s findings, it’s way too early to conclude that the possible harm calcium might cause outweighs the benefits studies have shown it provides.

If you’re not sure what to do — and heaven knows, the back-and-forth can be very confusing — ask your doctor to read this study, if he or she hasn’t already done so, and tell you what’s good or bad about it and what he or she recommends for you. Does your doctor think you should continue taking calcium supplements as you have done up to now or does he or she think you should stop taking the supplements?  And if you do stop taking them, ask about food sources of calcium. Which foods does the doctor recommend, in what amounts, and how often should they be consumed?  Be sure to ask about other calcium sources too, such as antacid tablets that contain calcium (like Tums®).

If you don’t have a health care professional to help you with this question, read’s Review of Calcium Supplements. Cautions and factors to consider if you are concerned are listed toward the end of the review. Or ask knowledgeable staff or nutritionists at your local health store.

Want to read the full text of the Heart article will find it in the June 2012 issue? See:  Calcium and cardiovascular disease. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study (EPIC-Heidelberg), Heart 98:920-925 doi:10.1136/heartjnl-2011-301345

© 2012, All rights reserved


Post a Comment

You must be logged in to post a comment.