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Cranberry juice 'does not prevent cystitis'

Cystitis cannot be protected against by drinking cranberry juice, scientists have said.

Many women have used the juice to treat mild forms of the condition, which is a stinging inflammation of the bladder, or to prevent infection recurring.

But now scientists in a review said they found no evidence that the juice, or supplements, can be used to prevent kidney or bladder infections.

The condition, normally brought on by a urinary tract infection (UTI), has been nicknamed “the honeymoon disease” as it can also be set off by irritation during sexual intercourse.

It was suggested that compounds in cranberries could stop bacteria adhering to cells lining the urinary tract and many websites and GPs have encouraged women with the inflamation to try cranberry juice, but analysis of the new findings from 24 studies of 4,473 participants went against this.

Four years ago, a review of 10 trials found women who took the juice or cranberry supplements suffered fewer UTIs than women who did not, but some studies examined in the new review revealed “small benefits” for recurrent infections, although the authors said these results were not statistically significant.

They said women would have to take two glasses each day for a long time to prevent just one infection.

There was no particular need for more studies studies of the effect because most studies done indicate a small benefit at best, with a big drop-out rate of participants.

One problem with evaluating these studies was that the level of active ingredients in the supplements was rarely reported so it was hard to say if levels would have been high enough to have an effect.

“More studies of other cranberry products such as tablets or capsules may be justified, but only for women with recurrent UTIs, and only if these products contain the recommended amount of active ingredient,” said lead researcher Dr Ruth Jepson, from the University of Stirling.

In another review, it was found deaths from serious conditions such as cancer or heart disease were not cut by general health checks, and researchers advised against a public health programme including them.

However, lead researcher Lasse Krogsboll, from the Nordic Cochrane Centre in Copenhagen, affirmed that the team was not saying doctors should stop performing tests or treatment.

Of 14 trials involving 182,880 people, some provided unreliable results, and the authors reported no evidence that general health checks reduced death rates in the long term, a conclusion based on nine reliable trials with 11,940 deaths.

Readers' comments (10)

  • I have been doing research at Rutgers University for the past 20 years and have found that cranberries prevent bacteria from sticking to bladder cells, which is the initial step in the urinary tract infection process. I think we need to keep these latest findings in perspective with the totality of cranberry research that has been done over the last 100 years. This latest review analyzed results from some of the clinical trials, using criteria that apply to studies on drug treatments. Cranberry is a food that comes in different forms (juices, powders, dried, etc.) making it difficult to compare results from different trials because the same form and dosage of cranberry were not used in each study.

    Interestingly, three new UTI clinical studies, published after this report was prepared, have shown significant benefits in children, with as much as a 65% reduction in UTIs and reduced use of antibiotics. Cranberries in many forms are enjoyed by millions of people globally on a daily basis. If women are currently consuming cranberry products, the results of this one review do not provide a reason for them to change their current practices. It is important that cranberry continue to be regarded and researched as a viable means to help address the public health challenge that UTIs and their treatment presents to antibiotic resistance. The effects of the studies are clinically important to the 15 million women in the US with UTIs each year. - Amy Howell, PhD

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  • Great to ear a posting from someone doing the research, thankyou Amy.
    NT, any chance of you posting the appropriate references for these research orientated pieces?

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  • Thanks Amy for your interesting and informative comment that contradicts this article.

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  • Yes, thank you, Amy. Anecdotally, I have used cranberry juice at the recommendation of my childhood urologist for over 45 years. Not only does it stave off rampant infections for me at times, but not mentioned in the above-article is the fact that it relieves much of the personal discomfort.

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  • Three new UTI clinical studies published after the Cochrane Review was prepared have indicated significant benefits, especially in children, with the participants experiencing as much as a 65% reduction in UTIs and subsequent use of antibiotics. (Afshan et al., J.Urology; Mutlu et al., ISRN Pediatr.; Uberos et al., Open Access J. of Clinical Trials). It is also important to note that a recent review contradicts the results of the Cochrane findings. In the July 9, 2012 publication of the Wang et al., Archives of Internal Medicine, scientists reviewed thirteen cranberry and urinary tract health trials with 1,616 subjects and concluded that cranberry-containing products are associated with protective effects against UTIs. In addition, Takahashi et al., Journal of Infection and Chemotherapy published a randomized clinical trial involving female patients with UTIs suffering from multiple relapses and the impact of cranberry juice. The results showed that cranberry juice prevented the recurrence of UTIs in a subgroup of this female population with 24-week intake of the beverage. This is another indication of the positive attributes of cranberries with respect to the urinary tract health.

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  • We were always told that drinking too much cranberry juice leads to the formation of renal calculii, as such the urologists in my trust didn't subscribe to the use of the juice

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  • redpaddy: Only people who already have kidney disease and who are prone to stones of calcium oxalate are at risk of stone formation using cranberry juice. No-one else according to the reseearch.

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  • Thanks Bob.

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  • No worries

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  • What a great set of comments. Thanks to all who have posted. I am student nurse with interest in the studies conducted into effects of cranberries especially as my daughter has a long history of recurrent UTI's. It's interesting that the main article states 'scientists' have found no evidence of positive effects but then Amy Howell comes back straight away with evidence to the contrary - but if a reader doesn't digest the comments under the article, they are left with a somewhat inaccurate picture.
    Can I say also, it is nice to see that people commenting have not been negative with each other, as is so often the case on the 'have your say' sections!

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