I’ve read that post-menopausal women should take 1500 mg. of calcium daily. How much supplemental calcium do you recommend? D.M.

Dear D.M.: The amounts of calcium supplementation generally recommended are based upon studies using calcium carbonate. Calcium carbonate is poorly absorbed and utilized by the body. It is estimated that only 10% of calcium in the carbonate form is absorbed. Therefore 1500 mg. of calcium carbonate provides approximately 150 mg. of useable calcium. Chelated forms such as calcium citrate and calcium hydroxyapatite are much more bioavailable. With an absorption rate of 40 % or more, just 500 mg. of calcium citrate or hydroxyapatite will supply 200 mg. of calcium to the body. This means that as little as 250 mg. of calcium citrate or hydroxyapatite daily premenopausally and 500 mg. daily postmenopausally should provide adequate supplementation. Other minerals including magnesium, potassium and boron and green plant supplements are also required to enable the body to utilize the calcium efficiently. –Dr. Peterson