For the best quality, choose brand names or large chain-store brands. Avoid tablets containing bone meal or dolomite, which may be contaminated with lead. Calcium is best absorbed in several doses, rather than all at once. The most popular calcium supplement, calcium carbonate, contains more calcium per tablet than calcium lactate, calcium gluconate or calcium citrate. Be sure to take calcium carbonate with meals because stomach acids help calcium absorption.
Chewable tablets are fairly inexpensive sources of calcium.
Calcium from food is better absorbed and used than calcium from pills. The best food sources of calcium are low-fat milk, cheese, yogurt, and canned fish with edible bones such as sardines and salmon. Tofu, some dry beans, tortillas made with lime-processed cornmeal, and dark green leafy vegetables like broccoli, kale and collards also provide calcium. Spinach is high in oxalates and its calcium is not absorbed well. Iron The most common iron supplement is ferrous sulfate, although other ferrous salts such as ferrous lactate, fumarate, glycine sulfate, glutamate and gluconate are also absorbed well.