The benefits of cranberry juice have been shown to be true for people suffering from urinary tract infections (UTIs), according to a new study.
Although it has long been touted as a treatment for the painful yet common infection, its usefulness has been debunked by some studies, including a 2012 review that looked at 24 trials.
This finding has now been debunked itself by a recent study from Australia's Flinders University. Researchers have found drinking the juice can cut the risk of repeat UTIs in women by more than a quarter and for children by more than half.
However, the fruit did not offer any benefits for elderly people, pregnant women or in people with bladder emptying problems.
According to the NHS, UTIs are usually caused by bacteria from poo entering the urinary tract through the urethra, the tube that carries urine out of the body. It causes symptoms like pain or burning while peeing, needing to pee more often, and blood in the urine.
Age also can play a part, with older adults and young children being more susceptible.
Researchers looked at 50 more recent trials that included almost 9000 participants, but weren't shocked by the finding.
"This incredible result didn’t really surprise us, as we’re taught that when there’s more and better evidence, the truth will ultimately come out," said lead author Dr Gabrielle Williams of Flinders University in Adelaide, Australia.
"UTIs are horrible and very common; about a third of women will experience one, as will many elderly people and also people with bladder issues from spinal cord injury or other conditions.
"Even back in 1973, my mum was told to try cranberry juice to prevent her horrible and frequent UTIs, and for her it’s been a saviour.
"Despite me niggling in her ear about evidence, she’s continued to take it daily, first as the nasty sour juice and in recent years, the easy to swallow capsules.
"As soon as she stops, wham, the symptoms are back. As usual, it turns out that mum was right. Cranberry products can help some women prevent UTIs."
Flinders University epidemiologist Dr Jacqueline Stephens, a co-author of the study, says if the UTI persists untreated it can move to the kidneys and cause pain and more complications, including sepsis.
She said: "Most UTIs are effectively, and pretty quickly, treated with antibiotics, sometimes as little as one dose can cure the problem. Unfortunately, in some people UTIs keep coming back.
"Without being sure if or how it works, some healthcare providers began suggesting it to their patients.
"It was a harmless, easy option at the time. Even centuries ago, Native Americans reportedly ate cranberries for bladder problems, leading somewhat more recently, to laboratory scientists exploring what it was in cranberries that helped and how it might work."
The majority of studies they looked at compared cranberry products with a placebo or with no treatment at all. They found that drinking cranberry juice or taking capsules reduced the number of UTIs women and children who were susceptible to them had.
She said: "The studies we looked at included a range of methods to determine the benefits of cranberry products.
"The vast majority compared cranberry products with a placebo or no treatment for UTI and determined drinking cranberries as a juice or taking capsules reduced the number of UTIs in women with recurrent cases, in children and in people susceptible to UTIs following medical interventions such as bladder radiotherapy."
While the results pointed at the positives of cranberries, the team suggests that more information is needed.
She added: "It’s important to consider that few people reported any side effects with the most common being tummy pain based on the results.
"We also did not find enough information to determine if cranberry products are more or less effective compared with antibiotics or probiotics in preventing further UTIs."
"This is a review of the totality of the evidence and as new evidence emerges, new findings might occur," said senior author Professor Jonathan Craig, vice president and executive dean of the College of Medicine & Public Health at Flinders University.
"In this case, the new evidence shows a very positive finding that cranberry juice can prevent UTI in susceptible people. We have shown the efficacy of cranberry products for the treatment of UTIs using all the evidence published on this topic since the mid-nineties.
"The earlier versions of this review didn’t have enough evidence to determine efficacy and subsequent clinical trials showed varied results, but in this updated review the volume of data has shown this new finding."
The study was published in the journal Cochrane Database of Systematic Reviews.
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