Medical Edge Newspaper Column

Calcium Supplements Unrelated To Kidney Cysts

April 17, 2006
DEAR MAYO CLINIC:
Can calcium supplements cause cysts to develop in the kidneys? -- Centerport, N.Y.

ANSWER:
Whether you have one or many cysts in your kidneys, there's no known direct link to calcium supplements.

It's not unusual for one or two cysts -- round sacs containing waterlike fluid -- to develop in the kidneys. Doctors don't know what causes cysts to appear, but they are increasingly common in people age 50 and older. The cysts are usually benign and don't require any treatment. Typically, the cysts are found when patients undergo tests or treatment for another condition.

Polycystic kidney disease is a rare disorder in which groups of cysts develop in the kidneys and other organs. It is most commonly inherited in an autosomal dominant fashion, in which about half of individuals in affected families have the disease. The condition can cause high blood pressure, abdominal pain and even kidney failure.

One symptom of polycystic kidney disease is kidney stones, which do have a calcium connection. About four out of five kidney stones are calcium stones. This is true whether or not a person has polycystic kidney disease. A number of health factors can cause high amounts of calcium in the urine, leading to kidney stones.

If you have a history of kidney stones, talk to your doctor about the advisability of calcium supplements. If you don't have kidney stones and are taking calcium supplements for your bone health, it's safe to continue doing so at recommended doses.

Calcium supplements are considered very safe. They may cause gas, bloating or constipation in some people. To minimize side effects, drink six to eight glasses of water daily, exercise and eat plenty of fruits, vegetables and whole grains.

-- Bart Clarke, M.D., Endocrinology, Mayo Clinic, Rochester, Minn.