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

Pure cranberry juice may be beneficial for your kidneys, according to the National Kidney Foundation, but what about pomegranate juice? The evidence is less conclusive, even for kidney stone treatment at home. Although there might be some benefits, people with kidney disease should be wary.

Cranberry juice has long been considered beneficial for your kidneys because it may have an impact on urinary tract infections (UTIs). According to the Cleveland Clinic, most studies are conflicting, though.

The claim is that an active ingredient, A-type proanthocyanidins, prevents bacteria from adhering to the bladder wall and causing a UTI. An infection can travel up to the kidneys and trigger a more serious infection, says the National Kidney Foundation.

However, while one review of studies published in July 2014 in Evidence-Based Medicine determined that cranberry juice and tablets did reduce the frequency of UTIs, another review published in February 2012 in Mayo Clinic Proceedings concluded they did not. As with most natural remedies, the current evidence is mixed and requires further research.

Since there is little risk in using cranberry juice to prevent UTIs, the Cleveland Clinic states that it can't hurt but may help. There's no research on whether pomegranate juice has any effect on UTIs.

Research is mixed on whether pomegranate juice can help with kidney stones. A study published in March 2018 in the International Journal of Molecular Sciences assessed the effects of several plants on the prevention and management of kidney stones.

Daily supplementation with pomegranate extract has been shown to lower the risk of kidney stone formation. However, it's worth noting that researchers specifically looked at pomegranate extract, not pomegranate juice.

There hasn't been much research on pomegranate juice and kidney problems, but one animal study published in September 2013 in the Kaohsiung Journal of Medical Sciences examined whether a variety of juices could affect kidney stone formation. For example, is there a benefit to pomegranate juice or apple juice for kidney stones?

The results: None of the juices, which also included cranberry juice and orange juice, were effective. However, if you're looking for treatment outside of juices, potassium citrate — the control in the study — which, according to the Mayo Clinic, makes the urine less acidic — was able to significantly reduce kidney stone formation.

Read more: Risks and Benefits of Pomegranate Juice

Drinking pomegranate juice may benefit hemodialysis patients, according to a study published in July 2012 in the journal Free Radical Biology and Medicine. Hemodialysis is a treatment for kidney disease, which filters waste and water from the blood, says the National Institute of Diabetes and Digestive and Kidney Diseases.

Researchers concluded that one year of pomegranate juice consumption had a positive impact on oxidative stress, inflammation and incidence of infections in people on dialysis. This natural remedy reduced their risk of death as well.

Additionally, people who are on dialysis often develop iron-deficiency anemia, according to the National Kidney Foundation, so they may need intravenous iron. This further aggravates a person's oxidative stress, which is already high because of the hemodialysis, notes a study published in June 2013 in Nutrition Research. Scientists concluded that consuming pomegranate juice for one year may reduce the impact of intravenous iron on oxidative stress.

Pomegranate juice is fairly high in the mineral potassium, which can be problematic for patients with chronic kidney disease (CKD). Maintaining proper levels of this mineral is essential for regulating your heartbeat, but people with moderately or severely impaired kidneys can't always balance those levels properly, according to the National Kidney Foundation. Therefore, they may develop high potassium levels, which can be dangerous.

Read more: 5 Health Benefits of Pomegranate Seeds That Pack a Powerful Punch

Each cup of pomegranate juice supplies 533 milligrams of potassium, according to the USDA. This is a good chunk of the recommended daily value of the mineral, which is 2,600 milligrams for adult women and 3,400 milligrams for adult men, as reported by the National Institutes of Health.

If you have CKD and want to drink pomegranate juice regularly, talk to your doctor and/or a dietitian to make sure that you're not overdoing it on potassium.