Is Pomegranate Juice As Good for a Person's Kidneys As Cranberry Juice?

Cranberry juice helps treat urinary tract infections, while pomegranate helps slow the buildup of cholesterol in your arteries. These fruits have a plethora of antioxidants, vitamins and nutrients that benefits your immune system and cardiovascular health. Cranberry and pomegranate juice can help improve your kidney function in different ways. However, they can have negative effects on your kidneys if used inappropriately.

A kidney stone is formed from tiny crystals, which may cause pain in the groin region and belly. Neither cranberry nor pomegranate juice helps alleviate kidney stones. Although cranberry juice is likely safe, drinking too much of it may cause kidney stones. According to MedlinePlus, cranberry juice is rich in a chemical called oxalate. When large amounts of this chemical are mixed with calcium, kidney stones may form. Therefore, those with a history of kidney stones are better off drinking pomegranate juice and should limit their consumption of cranberry juice.

Dialysis patients face an increased risk of mortality due to infections and heart disease. A preliminary study presented by the “American Society of Nephrology” in 2010 found that the antioxidants in pomegranate juice can help reduce infections and tissue damage. Dr. Batya Kristal and colleagues studied 101 dialysis patients and found that those who drank pomegranate juice three times a week for one year experienced a reduction in inflammation and free radical damage to cells. There is no evidence suggesting cranberry juice can improve health in dialysis patients. However, the Kidney Foundation recommends a cranberry juice cocktail as a beverage for adults starting hemodialysis.

A UTI is a common bacterial infection that occurs in the kidneys, ureters, urethra and bladder. Medline Plus reports that research indicates that cranberry juice can help prevent repeated UTIs in older women, pregnant women and hospitalized patients. There is no evidence that pomegranate juice helps combat UTIs, but its antioxidant properties can help boost your immune system.

Both cranberry and pomegranate have their uses in improving your kidneys' function. Pomegranate has more clinical evidence in treating a wider range of kidney problems, while cranberry juice only seems effective for UTIs. When you have chronic kidney disease, the potassium in your blood can rise to dangerous levels, which may cause heart rhythm problems. Pomegranate is high in potassium and cranberry is low -- limit the amount of pomegranate you eat or drink if you have chronic kidney disease.