|  | Conditions Treatments | Medical Conditions

What Chemicals Are Kidney Stones Made Of?

Kidney stones are one of the most painful medical conditions and affect nearly 3 million people each year. These stones are made up of chemicals that remain in the urine to form crystals. Once a stone has formed, medical intervention may be required to help it pass through the urinary tract. Some types of kidney stones can be prevented by following a diet low in the chemicals that cause these stones to form.

  1. Uric Acid

    • Uric acid kidney stones are composed of uric acid. This chemical is a waste product of purine metabolism and is excreted into the urine. When too much uric acid remains in the urine, crystals begin to form, and a uric acid kidney stone can develop. People who have too much uric acid in the blood, like those with gout, are at an increased risk for this type of kidney stone. Uric acid kidney stones may be prevented by following a diet that restricts the intake of foods that have high levels of purines. High-purine foods include red meats, alcoholic beverages and dishes prepared with yeast.

    Calcium Oxalate

    • Oxalate is a chemical that crystallizes when it binds with calcium. These crystals can build up in the urine and cause calcium oxalate kidney stones. Calcium oxalate kidney stones can be prevented by eating a diet that is low in oxalate. High-oxalate foods to avoid include chocolate, raspberries, gooseberries, string beans, wax beans, spinach, parsley, eggplant, draft beer, nuts, rhubarb, strawberries, soy products, sweet potatoes and wheat germ. Calcium restriction is not necessary unless a medical condition that causes the body to absorb too much calcium is present.

    Calcium Phosphate

    • Calcium phosphate is the combination of calcium with a phosphate group. When calcium phosphate is excreted into the urine in high amounts, it can crystallize and form calcium phosphate kidney stones. Adjusting the diet can help prevent this type of kidney stone, as calcium phosphate thrives in alkaline environments. Foods that can acidify the urine, such as cranberry extract or a diet rich in whole grains, can help prevent the buildup of calcium phosphate in the urine. Grains that contain bran can also help prevent these stones because they bind with calcium before it becomes concentrated in the kidneys.

    Cystine

    • Cystine is an amino acid that is found in proteins. While cystine kidney stones are less common than other types of kidney stones, they can occur due to high levels of cystine in the urine. Dietary approaches to preventing these stones involve making the urine more alkaline. This can be done by increasing your intake of citrate. Since sodium increases cystine excretion, reducing your sodium intake can also help to prevent this type of kidney stone.

    Struvite

    • Struvite stones are also known as infection stones because they result from a bacterial infection in the urinary tract. Struvite, also called ammonium magnesium phosphate, can crystallize in the urine and form painful kidney stones. This chemical is associated with gram-positive bacteria, gram-negative bacteria and yeast. The bacteria causing the stones should be treated with antibiotics. This type of stone may also be prevented with the use of urease inhibitors that decrease the amount of ammonia in the urine.

Medical Conditions - Related Articles