Calcium is a nutrient that contributes to bone and tooth healthy and is also essential to the normal functioning of your muscles and nerves. The McKinley Health Center at the University of Illinois at Urbana-Champaign recommends a daily intake of 1,000 to 1,300 mg of calcium for adults for optimum health. Factors that can block or decrease calcium absorption include medications you take and the foods you eat.
Medications and Therapies
Acid-blocking medications used for heartburn and other gastrointestinal conditions can block the absorption of calcium through the stomach walls. Stomach acids break down food during the digestive process, allowing the nutrients to become absorbed into your body. Medications designed to stop acid production or decrease the amount of acids present in your stomach can have a negative effect on calcium. The New York State Department of Health suggests that you take a calcium supplement that contains calcium citrate, a form of the mineral that can be absorbed without stomach acids.
Lack of Vitamin D
Vitamin D and calcium go hand in hand in maintaining bone health and regulating various balances within your body. One of vitamin D's main roles in the body is to maintain your balance of calcium. If you are not getting enough vitamin D, your body won't be able to process calcium properly. Allow your body to absorb calcium effectively by consuming the recommended daily allowance of vitamin D; children should get 200 international units and adults require 400 to 600 IU, depending on their age.
The foods you eat may play a role in how much calcium is absorbed into your system. Foods that contain compounds such as oxalic or phytic acids, including spinach, sweet potatoes, beans, nuts, rhubarb, celery and beets, can decrease the amount of calcium that's absorbed when eaten at the same time as milk and other calcium-rich foods. If you have a problem with lower-than-normal blood calcium levels, try to drink your milk in between meals if you routinely eat items that cause less calcium to be absorbed during digestion.
Too Much Calcium
The thought sounds contradictory, but taking too much calcium at one time may actually inhibit its absorption into your body. The Office of Dietary Supplements, a division of the National Institutes of Health, explains that taking more than 500 mg of a calcium supplement or its equivalent through diet can lower the amount of the mineral that your body is able to absorb.