Do Calcium Supplements Build Up In The Kidneys?

When you eat calcium-containing foods, your body normally takes what it needs and passes the rest to your kidneys for elimination in your urine. However, in some people, calcium builds up in the kidneys and forms part of abnormal accumulations called kidney stones. Any source of calcium you consume, including supplements, can potentially contribute to this process.

Avoiding Excessive Consumption

Some people are susceptible to kidney-stone formation, while others are not, according to the National Kidney and Urologic Diseases Information Clearinghouse, or NKUDIC. If you have a tendency to form kidney stones, excessive consumption of any type of calcium can trigger a buildup of the mineral inside your kidneys. Adults between the ages of 19 and 50 have a maximum calcium tolerance of 2,500 mg per day, while adults over 50 have a maximum tolerance of 2,000 mg. Adolescents have a maximum daily tolerance of 3,000 mg. Younger children have maximum tolerances that range from 2,500 mg down to 1,000 mg.

Maintaining Recommended Intakes

Although it may seem counterintuitive, you can decrease your chances for calcium buildup in your kidneys by keeping your calcium intake high enough to meet recommended daily intakes, the NKUDIC and the University of Arizona report. However, make sure to get your calcium from food sources if at all possible. Use of calcium supplements can increase your risk of kidney buildup even at recommended levels. Men between the ages of 19 and 70 and women between the ages of 19 and 50 need 1,000 mg per day. Men over 70 and women over 50 need 1,200 mg a day, while older children and adolescents need 1,300 mg.

Calcium Absorption

Calcium only passes to your kidneys if you don't absorb it in your small intestine, the University of Arizona explains. You can decrease your risk of calcium buildup in your kidneys by purchasing a supplement that dissolves properly and makes itself available for absorption. Supplements that dissolve properly typically have the approval of the U.S. Pharmacopeia, or USP, which sets dissolution standards. To meet USP guidelines, a supplement must contain at least 90 percent of the calcium content claimed on its label. It must also dissolve in a period of 30 to 40 minutes.

Considerations

You can only absorb so much calcium at one time, and use of supplements that contain more than 500 mg in a single dose can result in a lower absorption rate, the National Institutes of Health's Office of Dietary Supplements notes. Supplemental calcium typically comes in one of two forms: calcium carbonate and calcium citrate. If you use calcium carbonate, take it with food to maximize absorption. People with reduced amounts of stomach acid usually have an easier time absorbing calcium citrate. Consult your doctor for more information on calcium supplements and their potential to build up in your kidneys.