Calcium kidney stones form in individuals with high levels of calcium in their kidneys and urinary tract. Over time, calcium can build up in the kidneys and urinary tract as a result of a number of genetic, lifestyle and dietary factors. Understanding the causes of calcium kidney stones can help those at risk for this condition prevent the onset of kidney stone disease.
Genetic Factors
The National Institute of Diabetes and Dietary and Kidney Diseases (NIDDK) explains that calcium kidney stones occur in individuals who absorb too much calcium from food or have problems excreting calcium. This condition is generally referred to as hypercalciuria. Hypercalciuria is an inherited genetic condition and may account for the cause of over 50 percent of kidney stone cases. As calcium builds up, it can form solid crystals or stones in the intestines, kidneys and urinary tract.
Dietary Calcium
Interestingly, dietary sources of calcium are not thought to affect the formation of calcium kidney stones. According to the Mayo Clinic, individuals with a calcium-deficient diet are more at risk for developing kidney stones. Those hoping to prevent calcium kidney stones should continue to eat calcium-containing foods.
Dietary Supplements
While there is no direct evidence that calcium supplements can cause kidney stones, the Mayo Clinic and the NIDDK recommend that individuals at risk for calcium kidney stones avoid calcium supplements. Vitamin D supplements, which help the body absorb calcium, should also be avoided. It is also recommended to limit the intake of calcium-based antacids.
Dietary Oxalate
Oxalate is a compound found in a number of vegetables and other foods that can combine with calcium in the urinary tract to form solid crystals or stones. Oxalate-containing foods include spinach, beets, chard, soy crackers, chocolate and some teas. The Oxalosis and Hyperoxaluria Foundation and the NIDDK recommend that individuals at risk for calcium kidney stones avoid oxalate-rich foods.
Acidic Urine
As you may remember from chemistry class, calcium precipitates from solution under acidic conditions. Similarly, as described by the NIDDK, calcium can precipitate in the kidneys and urinary tract as the urine becomes acidic. A number of genetic and dietary factors can affect urine acidity. Diets high in meat and protein can increase acid levels in the urine. Obese individuals and diabetics can also have acidic urine as a result of insulin resistance.
