Using caution with calcium

As is almost always the case in life, having too much of a “good thing” doesn’t mean we’ll be happier or healthier folks. And when it comes to our eternal pursuit of health and well-being from dietary supplements, this adage is proven true time and time again.


In a study published in the British Medical Journal, researchers reported that calcium supplements could increase the risk of heart attack by as much as 30 per cent.


According to University of British Columbia nutrition professor, Dr. Susan Barr, this carefully conducted study revealed that high intakes of supplemental calcium, consumed without vitamin D, appear to slightly increase the risk of cardiovascular events in older adults. 


However, Barr cautions that the effects of taking both a calcium and vitamin D supplement are still not known since the study only included trials of large calcium doses.


“The study authors speculate that a possible mechanism for the increased risk of heart attack may be due to rapid increases in serum calcium [meaning the amount of calcium in our blood], which occur after consuming a large supplemental dose”, says Barr in an interview. 


Research has repeatedly shown that we’re better off getting calcium from food rather than pills; the increase in serum calcium is much less when the nutrient is coming from dietary sources such as low fat milk products, fortified soy beverages and some leafy greens. 


“This finding supports the concept that if calcium supplements are needed because of food dislikes, a milk allergy or lactose intolerance, they should be taken with meals and in divided doses”, adds Barr.


The University of California, Berkeley, Wellness Letter recommends that we spread our calcium intake throughout the day so we don’t exceed 500 milligrams from food and supplements at any one time. Taking in more of the nutrient is futile because the more we get at one sitting, the smaller the proportion our bodies absorb. 


A good rule of thumb is to take no more than 300 milligrams of elemental calcium from a supplement at a meal or snack. Check the package label to see how much elemental calcium the supplement provides per tablet or dose. 


Also look on the package for the type of calcium used in the supplement; those made with calcium carbonate, calcium citrate or calcium citrate malate are considered high-quality because they’re well absorbed by the body.


Calcium carbonate requires stomach acid in order to be absorbed properly, so it’s best to take this supplement just after finishing a meal or snack. Calcium citrate and calcium citrate malate aren’t as dependent on stomach acid; they can be taken before or after eating. 


Although it’s important to consult with your physician first, anyone taking medications that reduce stomach acid such as Prilosec or Zantac should consider taking calcium citrate. Lower amounts of stomach acid means calcium carbonate won’t be well absorbed..


Calcium citrate or calcium citrate malate are most likely better choices for individuals over 50 since stomach acid production tends to decrease with age.


Ultimately, it’s important for us to aim for the recommended daily intakes of calcium (1000 mg for adults 19 to 50 years of age; 1200 mg, for those who are older) and not exceed them excessively. 


If we’re taking a calcium supplement to meet our needs we should also be consuming vitamin D to promote its absorption. Health Canada recommends that all adults 50 and older take 400 International Units (IU) of vitamin D each day. And unless we’re under medical supervision, our intake shouldn’t exceed 2000 IU.


For more information regarding calcium-rich foods, visit the B.C. Dairy Foundation to order their Calcium Calculator brochure.