When is too much of a good thing a bad thing?
For women concerned about losing bone mass and developing osteoporosis or brittle bones, the answer might be in that bottle of calcium tablets.
UHNBC nutritionist Lynne Wood says while women most often are told they aren't getting enough calcium in their diets, there are some dangers associated with taking too much of the essential nutrient. Excess intake of calcium can increase risk of kidney stones, constipation and reduce the body's ability to absorb iron and zinc.
A British Medical Association study published last April has linked consumption of calcium tablets to an increased risk of cardiovascular disease, including heart attacks and strokes.
"With all vitamins and minerals, people tend to overdo the supplements," said Wood, the clinical dietitian manager at UHNBC. "You might see over-supplementation happening in the 51-and-older age group because people in that age group are trying to prevent osteoporosis"
"Dietitians always recommend getting your calcium from food first. Unless you can't eat it, because you are lactose-intolerant or for any other reasons, we might recommend a supplement to top up."
Antacids such as Tums and Rolaids contain calcium carbonate, a less expensive form of the mineral than the calcium citrate found in over-the-counter supplements. Wood said antacids should be taken in moderation with meals to increase the absorption rate.
"Any of these forms of calcium if you were to take them in excess, could lead to any of those side effects, like constipation," said Wood.
Calcium is is the most abundant mineral in human bodies, with all but one per cent of it stored in bones and teeth. It's needed to enable muscle movement, and to allow nerves to carry messages from the brain. It also helps vessels move blood and helps enable the release of hormones and enzymes.
Milk, yogurt and cheese are the most calcium-rich foods, and they also contain Vitamin D, which helps increase absorption. Kale, broccoli, cabbage, canned fish, and most grains also contain calcium. Alcohol and caffeine reduce the calcium absorption rate. Wood said extreme exercising can decrease the body's calcium supply.
Health Canada recommends teenaged girls and pregnant adult women receive 1,300 milligrams of calcium per day, while post-menopausal women aged 51-70 need 1,200 mg. All adults aged 19-50 need 1,000 mg per day, adult men aged 51-70 need 1,000 mg, while all adults 71-and-older require 1,200 mg daily.
The upper daily limit for teenagers is not to exceed 3,000 mg, adults 19-50 should keep it to 2,500 mg, and adults 51-and-older should never top 2,000 mg per day.
"People might recommend in excess to the upper limits if they have osteoporosis or certain disease states that warrant taking more calcium," said Wood.
She said most people can absorb only 500 mg of calcium at once. Whatever the body can't process is excreted as urine.
