Are Cranberries Good for UTI Prevention?

You might have heard that cranberries help prevent urinary tract infections (UTIs). But are these berries really as medicinal as they are tart and tasty?

The research on this isn’t totally clear. Some studies have found that drinking cranberry juice or taking cranberry pills can prevent UTIs, especially in women who are at risk for these infections. But others haven’t come to that conclusion.

Cranberries don't seem to work for everyone. And they don’t treat UTIs that you already have.

The American College of Obstetrics and Gynecology says that unsweetened cranberry juice and cranberry supplements may make UTIs less likely, but that it’s not yet clear how much you need to take and for how long.

How Might It Work?

Scientists used to think that cranberries protected against UTIs by making urine more acidic, which is less friendly to bacteria like Escherichia coli (E. coli) that are usually to blame.

But now, researchers have a different theory: that cranberries make it harder for infection-causing bacteria to stick to the urinary tract walls.

It could be that nutrients in cranberries change the bacteria so that they can't stick to the urinary tract. Or it may be that cranberries create a slippery coating on the urinary tract walls that makes it hard for E. coli to get a good grip.

Keep in Mind

Because of their acidity, cranberries can be hard for some people to take.

Cranberry juice is high in salts called oxalates, which can make kidney stones more likely, especially if you already tend to get these types of stones.

If you take the blood-thinning medication warfarin, you should avoid cranberry products, because cranberries can interact with warfarin and cause bleeding.

If you like cranberry juice and it doesn't bother your stomach, affect another condition or your meds, it’s an option.

If you decide to take supplements, it’s best to talk to your doctor first.

WebMD Medical Reference Reviewed by Carol DerSarkissian on November 21, 2016

Sources

SOURCES:

American Family Physician, August 2008.

Journal of Family Practice: “Does cranberry juice prevent or treat urinary tract infection?”

Journal of Urology: “Effect of cranberry juice consumption on urinary stone risk factors.”

Mayo Clinic: "Urinary Tract Infection."

News releases, Science Daily.

British Medical Journal: “Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women.”

The Canadian Journal of Urology: “A randomized trial to evaluate effectiveness and cost effectiveness of naturopathic cranberry products as prophylaxis against urinary tract infection in women.”

Cochrane Database of Systematic Reviews: “Cranberries for preventing urinary tract infections.”

National Kidney and Urologic Disease Information Clearinghouse: “What I need to know about Urinary Tract Infections.”

National Center for Complementary and Alternative Medicine: “Urinary Tract Conditions: Examining the Evidence on Cranberry and Saw Palmetto.”

American Congress on Obstetrics and Gynecology: “Urinary Tract Infections (UTIs).”

National Center for Complementary and Alternative Medicine: “Cranberry.”

© 2016 WebMD, LLC. All rights reserved.