About 90% of kidney stones contain calcium. Most commonly, the crystals are made of calcium oxalate, and occasionally, they are made of calcium phosphate. Less commonly, stones are made of uric acid, cystine or struvite. No matter what kind of stone you have, your doctor can give you specific advice.
Calcium oxalate stones
For those with calcium oxalate stones, it may help to avoid foods that are high in oxalate. Oxalate is a natural chemical found in many foods. Of the oxalate found in urine, about two-thirds is produced by the body's metabolism and one-third comes from dietary sources.
Unfortunately, researchers are not sure how much oxalate found in a particular food gets absorbed by the body. Therefore, the oxalate content of a food may be misleading. Some foods that are particularly rich in oxalate include:
A comprehensive list can be found at Litholink.com
Uric acid stones
For those with uric acid stones, it may help to avoid foods that are high in purine content. Metabolism breaks purines down to uric acid (a waste product). If uric acid builds up in the body or the urine, it can lead to gout or kidney stones made of uric acid. For people with a history of gout or uric acid stones, most doctors recommend reducing the amount of purine in the diet.
High purine foods include:
- Liver and other organ meats
- Anchovies, sardines, herring
- Scallops, mussels
- Meat extracts
Moderately high purine foods include:
- Asparagus, cauliflower, spinach, mushrooms, green peas
- Meat, poultry
- Fish, shellfish
- Dried peas,
For those with struvite stones, it is recommended that urinary tract infections be treated aggressively.
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