Cranberry juice may be effective in preventing recurrent UTIs in some people, review finds

A new study suggests that cranberry juice has gone beyond a mythical prevention of urinary tract infections (UTI) to become a real deal – for some people.

The global review by medical scientists from Flinders University in South Australia and Westmead Children’s Hospital in New South Wales found that cranberry juice or supplements may reduce the risk of infections repeated symptomatic urinary tract in some women over a quarter, and in children over a half.

For people who are susceptible to UTIs following medical procedures, such as radiation therapy to the bladder, this risk is reduced by about 53%.

But the review showed no benefit for the elderly, pregnant women, or people with bladder emptying problems.

A UTI is a bacterial infection of the bladder, kidneys or urethra and affects one in two women during her lifetime, with many people suffering from more than one infection.

The researchers said the review is the first since 2012, which showed no benefit from the products.

The Cochrane Review update includes 50 more recent trials of cranberry products, covering nearly 9,000 participants.

Lead author and executive dean of Flinders University College of Medicine and Public Health, Jonathan Craig, said the benefits of cranberry products became apparent when the scope of the review was broadened.

“Earlier versions of this review did not have enough evidence to determine effectiveness and subsequent clinical trials have shown mixed results, but in this updated review, the volume of data has shown this new finding,” said he declared.

The researchers said the anecdotal benefits of cranberries date back centuries.

Lead author Gabrielle Williams said she was not surprised by the result – and that the cranberry legend had been passed down through her own family.

“In 1973, my mother was told to try cranberry juice to prevent her horrible and frequent urinary tract infections, and for her it was a salvation,” she said.

“Although I taunted her in her ear about the evidence, she continued to take it daily…as usual, turns out mom was right.”

Co-author and Flinders University epidemiologist Jacqueline Stephens said preventing UTIs was crucial to avoiding the risks associated with untreated infections, including sepsis in extreme cases.

“Most UTIs are treated effectively and fairly quickly with antibiotics, sometimes as little as one dose can solve the problem,” she said.

“Unfortunately, in some people, UTIs keep coming back.”

Dr Stephens said the review did not examine the use of cranberries for the treatment of UTIs.

Dr Stephens said the majority of studies examined in the review compared cranberry products to placebo or no treatment for UTIs.

“They might still get UTIs, but it would be less than they would normally get if they did nothing,” she said.

She said the researchers also found no difference between the results of studies done by juice companies or cranberry product makers and those done by academic institutions or hospitals.

“As researchers doing these reviews, we’re always looking at who has a vested interest in the results,” Dr Stephens said.

“It’s really important to look at who is funding these research projects and trials – more and more reviews are being put on these now.”

The review did not find enough information to determine whether cranberry products are more or less effective compared to antibiotics or probiotics in preventing more UTIs.