Cranberry juice UTI. What is the evidence for treatment and prevention.
Advice for patients

Cranberry juice and UTI

Urinary tract infection (UTI) is a common infection which can affect the bladder, urethra or kidneys. UTI mostly experienced by women, however, men can also get it. UTI can be uncomfortable but usually goes on its own without any treatment. Depending on the symptoms or in certain situations patients need to see their GP to get appropriate antibiotic treatments. To learn more about UTI and when to see your GP go to the NHS website. This post will focus on the use of cranberry juice in UTI treatment and prevention.

Why Cranberry juice in UTI?

Use of cranberries in the treatment of bladder infections goes back hundreds of years ago to Native Americans who used cranberries for medicinal purposes. This idea was confirmed by some laboratory studies which shower that certain chemical found in cranberries (called proanthocyanidins / PACs) prevent bacteria that cause the infection to stick to cells that compose the urinary tract. The model used in this study was not a human urinary track but a silicone surface and lab-grown E. Coli bacteria exposed to a cranberry juice. E. Coli bacteria are responsible for the majority of uncomplicated urinary tract infections. Overall there is strong evidence confirming the hypothesis that bacteria adherence to the urinary tract can be decreased, however, no quality evidence exists to support the use of cranberry juice/products in treatment or prevention of UTIs as we learn in the following paragraphs.

The best evidence for the use of cranberry juice in UTI treatment and prevention comes from well-respected Cochrane Collaboration who looks at different studies to provide reliable information.

Cranberry juice – UTI treatment

Currently, there is no good evidence from studies suggesting cranberry juice is effective in the treatment of UTIs. Well designed studies, for example, double-blind studies (part of subjects unaware of treatment taken) comparing cranberry juice with placebo are needed to assess the effectiveness of cranberry juice in the treatment of UTI (Cochrane, 1998).

Cranberry juice – UTI prevention

Cochrane Collaboration assessed 24 studies (over 4000 subjects) comparing cranberry juice with placebo or other treatments in the prevention of UTIs. Although some reduction of UTIs were seen in people using cranberry juice, Cochrane concluded that the difference between the use of cranberry juice and placebo or no treatment was not significant. Additionally, many participants across different studies simply stopped drinking the juice. Cochrane also added that drinking cranberry juice in the long term may be unacceptable by many and should not be recommended as a method of UTI prevention.

To sum up, there is little evidence suggesting cranberry products help to treat or prevent UTIs. Despite this most over the counter products sold in a pharmacy for symptomatic relief of UTIs are of cranberry flavoured to make it more appealing to the public. The actual active ingredients used are sodium or potassium citrate which help to control symptoms of UTIs by making the urine more alkaline.

References:

Cochrane (1998). Still waiting for evidence about whether cranberries are a useful treatment for urinary tract infections. Available at: https://www.cochrane.org/CD001322/RENAL_still-waiting-for-evidence-about-whether-cranberries-are-a-useful-treatment-for-urinary-tract-infections Accessed on 13/09/19

I am a community pharmacist working in UK. I blog about drugs, health and pharmacy.

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