Oxalate Calculi Diet

Kidney stones are a painful disorder of the urinary tract that afflicts several million Americans each year. There are many factors that can increase your risk of developing kidney stones; in most cases, there is no one single cause. If you are prone to this disorder or have developed kidney stones in the past, however, there are a number of changes you can make to your diet to reduce the chance of a recurrence.

Calcium Oxalate Stones

• Calcium and oxalate are chemicals that constitute an important part of our diet. If they're present in excessive levels in the urine, however, under certain conditions they can combine to form calcium oxalate, an insoluble compound that doesn't dissolve well in water. The calcium oxalate may then separate from the urine and crystallize to form a hard mass called a kidney stone. If the stone is very small, it will pass out in the urine without any symptoms. Larger stones may become trapped in the urinary tract, obstructing the flow of urine and usually causing a sharp cramping pain in the area of the kidneys or the lower abdomen.

Risk Factors

• Several rare genetic disorders, including renal tubular acidosis and hyperoxaluria, can place you at risk for developing kidney stones. People who are obese or who have a family history of kidney stones may also be at increased risk. Dehydration and diets high in sodium, protein and sugar are also common risk factors.

Treatment

• Small stones can be flushed out by drinking more water. Larger stones may require surgery or a procedure called extracorporeal shock wave lithotripsy, where sound waves are used to shatter the kidney stones into small fragments. Doctors will sometimes prescribe medications to help prevent a recurrence.

Diet Changes

• Drinking more water is the best measure you can take to help reduce your risk of forming kidney stones. The National Institute of Diabetes and Digestive and Kidney Diseases recommends that if you've had kidney stones in the past, you should drink at least enough water to produce two quarts of urine a day. According to the Mayo Clinic, one study found that drinking tea might also reduce risk, although some teas contain high levels of oxalate and are therefore not recommended. There's also some limited evidence that citrus drinks containing lemon or orange may help, because the citric acid can help to keep the calcium levels in your urine low. There haven't been any large-scale studies to confirm this, however, so more research is needed before doctors can definitively determine whether lemon or orange juice reduces your risk.

Foods to Avoid

• If you've had calcium oxalate stones in the past or have a family history of this disorder, there are certain foods you may want to avoid. According to the National Institute of Diabetes and Digestive and Kidney Disease, it's best to maintain a diet low in salt and animal protein such as meat, eggs and fish and to avoid foods high in oxalate, like spinach, rhubarb, nuts, wheat bran and tea. It's thought that vitamin C and D supplements can also play a contributing role, so you'll want to limit your intake of these supplements and calcium supplements. Unlike calcium supplements, calcium-rich foods are not believed to have any effect on your risk of developing kidney stones. The institute notes that grapefruit juice has been found to increase the risk of developing kidney stones.