Problems of calcium megadosing

Calcium is the most abundant mineral in the body, and bones contain about 99 per cent of all its calcium. In the bones, the calcium is found in the form of calcium phosphate salts, not as pure calcium. About 85 per cent of the body's phosphorus is stored in the bones.

Lack of enough calcium prevents bone deposition and contributes to thinner bones. Too much calcium can encourage kidney stones and gallstones. Insufficient phosphorus prevents the body from creating the necessary calcium salts and weakens the bones; excess phosphorus in the form of phosphoric acid (found mainly in soft drinks, preservatives and meats) can stimulate the release of calcium from the bones and thereby weakens them as well.Magnesium is needed to stimulate the absorption of calcium into the bones. If there is a lack of magnesium, calcium taken as mineral supplements may not go into strengthening the bones, but will remain in the bloodstream instead, perhaps contributing to kidney stones or gallstones.

Nan Kathryn Fuchs, PhD, a nutritionist at The Health Center in Santa Monica, California, and columnist for the Women's Health Letter, points out that while magnesium helps the body absorb and utilise calcium, excessive calcium prevents the absorption of magnesium, and calcium without magnesium may create either calcium malabsorption or magnesium deficiency.

Increasing magnesium intake while lowering calcium intake to 500 miligrams per day has been shown to increase bone density. Magnesium is found in whole grains, beans, fruits and fresh vegetables; it is refined out of sugar, white flour and white rice. Both sugar and alcohol cause magnesium to be excreted in the urine.