Do Cranberries Really Prevent Urinary Tract Infections?

Urinary tract infections (UTI) affect up to 60% of women over the course of their lifetimes. These infections result in bothersome symptoms including frequent, painful urination. They lead millions of people to seek medical care and cost billions of healthcare dollars each year. Is it any wonder that we would hope to find some way to prevent recurrence of these infections? For many, that hope has been placed in the tart little berry that makes its appearance each Thanksgiving — the cranberry.

How effective are cranberries at preventing infection?

Cranberry juice: Early on, several studies indicated that cranberry juice was effective in preventing recurrence of urinary tract infections. A class of chemicals called proanthocyanidins (PAC), found in cranberries, is thought to keep E. coli (the most common cause of urinary tract infections) from binding to bladder cells. It seemed to make sense that drinking cranberry juice would keep infections from recurring. However, PAC breaks down after 10 – 12 hours meaning people would need to drink cranberry juice twice daily to maximize the benefit. Many studies show a lot of people just don’t like the tart taste of cranberry juice and stop drinking it. Sorry, but the sugar-sweetened 10% juice cocktail won’t cut it when it comes to urinary tract health.

As more studies are done, fewer of them have shown a benefit and, overall, the evidence for cranberry juice has been questioned. When taken as a whole, it seems more likely that cranberry juice doesn’t make much of a difference in preventing infections.

Cranberry extracts: There are studies that show benefits from capsules containing extracted PAC, especially in certain populations that are at high risk of getting new infections. Unfortunately, these extracts suffer from a lack of standard composition. The amount of PAC from one supplement to another varies greatly.

For example, one study found that the amount of PAC across seven different cranberry extracts varied by 30 times. So, one brand of extract contained 30 times the amount of PAC compared with another. With so much variability, it is difficult to know whether or not these capsules can actually prevent infections.

What to do: There are studies ongoing for both cranberry juice and cranberry extract supplements that may find particular doses effective, or that certain types of people may benefit, so stay tuned. There are also compounds such as d-mannose sugar that may prove to be useful.

For women with recurrent urinary tract infections, a doctor’s visit can determine whether or not an underlying urologic problem could be to blame. Complications from previous surgeries and our over-use of antibiotics may also explain recurrent infections.

If you’re experiencing signs of a urinary tract infection, or recurrent infections, schedule an appointment with us to learn more about your options.