With a host of different manufacturers telling you their calcium product is the best for you, it is hard to know the truth.

Expert Michele Bellatoni said calcium carbonates have the most milligrams of elemental calcium but we absorb calcium citrate, lactate and glucanate more efficiently.

"Per pill they offer about half the amount of what carbonates offer, so they may look more expensive," she said.

Dr. Bellatoni warned that coral calcium and those made with unrefined oyster shell, bone meal or dolomite may contain lead or other toxic metals. Calcium supplements need to dissolve in the stomach for calcium to absorb. Chewable and liquid supplements dissolve well because they break down before entering the stomach. The recommended daily dose of calcium has increased from 1000 milligrams to 1200 for women in the US. Recent research shows that the body is only able to absorb a maximum of 500 to 600 milligrams at a time. So it is suggested that people take small doses through the day – 600 in the morning and 600 in the evening. Gas, bloating and constipation are side effects of calcium supplementation for some. Dr. Bellatoni suggests taking calcium with acidic juice, and increasing fibre and water consumption, to help alleviate the problem.