Digitalis preparations Heartbeat irregularities. Iron supplements Decreases absorption of iron unless vitamin C is taken at same time. Magnesium-containing medications Increases blood level of both. or supplements Oral contraceptives and May increase calcium estrogens absorption. Increases chance of heartbeat irregularities. Stimulates bone loss.
Alcohol decreases absorption.
Beverages Tea decreases absorption. Coffee decreases absorption. Don't take calcium with milk or other dairy products so your body can absorb the most calcium from food AND calcium supplement. Foods Avoid eating spinach, rhubarb, bran, whole-grain cereals, fresh fruits or fresh vegetables at same time you take calcium. They may prevent efficient absorption.