Calcium Carbonate and Kidney Stones

Approximately 7 percent of American women and 13 percent of American men will have a kidney stone at some time in their life, according to John Asplin, M.D., Medical Director of the Litholink Corporation in “Harrison’s Principles of Internal Medicine.” There is more than one type of kidney stone and calcium carbonate may or may not increase the risk of developing one.

The Types of Kidney Stones

There are four main types of kidney stones. An estimated 75 to 85 percent of all stones are made of calcium oxalate or calcium phosphate, and approximately half of the people who develop a calcium stone will experience another one within 10 years, writes Dr. Asplin. The next common type is called a struvite stone, which is made of magnesium, ammonium and phosphate. There are also uric acid stones and cystine stones.

How Kidney Stones Form

Calcium oxalate and calcium phosphate stones primarily form when people have a high amount of calcium in their urine, explains Glenn Preminger, M.D., Director of the Comprehensive Kidney Stone Center in “The Merck Manual for Healthcare Professionals.” They can also develop from a kidney disease called renal tubular acidosis, from having a low urine level of a substance called citrate, or a high amount of oxalate or even vitamin C. Struvite stones develop from a urinary tract infection caused by certain bacteria, while a high level of uric acid can cause uric acid stones, and a kidney disorder can lead to cystine stones.

What is Calcium Carbonate?

Calcium carbonate is a supplement that provides calcium to people who do not get enough calcium in their diet. It is also used as an antacid. Susan Ott, M.D., Professor of Medicine at the University of Washington explains that some manufacturers use calcium carbonate as a supplement while others use calcium citrate, but the intestines equally absorb both kinds. It is cheaper, however, for manufacturers to make calcium carbonate in a form that takes longer to dissolve. Dr. Ott writes about one patient who found an undissolved calcium tablet in her apron pocket after the apron had been through the washer and dryer.

Calcium Carbonate and Kidney Stones

The recommended dose of calcium for people 19 to 50 years old is 1,000 milligrams every day and 1,200 milligrams each day for those over 50 years old, according to the National Institutes of Health. In addition, the intestines absorb calcium better if it is taken several times during the day. According to Dr. Ott of the University of Washington, if people have more than 2,000 milligrams of calcium carbonate every day, they are at an increased risk of developing kidney stones.