The review includes 50 studies with a total of 8857 randomized participants.
A recent Cochrane review has found that cranberry products may help reduce the risk of urinary tract infections. The review includes 50 studies with a total of 8857 randomized participants. Of these 50 studies, 45 of them compared cranberry products with placebo or no specific treatment in six different groups of participants. Of these 45, 26 could be meta-analyzed for the outcome of symptomatic, culture-verified UTIs. Moderate-certainty evidence found that cranberry products reduced the risk of UTIs.
When divided into groups based on treatment indication, cranberry products “probably reduced” the risk of symptomatic, culture-verified UTIs in women with recurrent UTIs, in children, and in people with a susceptibility to UTS due to an intervention such as bladder radiotherapy. However, the review found that cranberry products may have little to no benefit in elderly institutionalized men and women, pregnant women, or adults with neuromuscular bladder dysfunction with incomplete bladder emptying.
In the review, three studies compared cranberry products with probiotics , six compared cranberry products to antibiotics, one study compared cranberry tablets with cranberry liquid, and two studies compared different doses of proanthocyanidins (PACs). Results showed that compared to antibiotics, cranberry products offered little or no difference to the risk of symptomatic, culture-verified UTIs or risk of clinical symptoms without culture. When compared to probiotics, cranberry products may reduce the risk of symptomatic, culture-verified UTIs. However, the review was unable to ascertain whether efficacy differs between cranberry juice or tablets, or between doses of PACs, as the certainty of the evidence was very low.
According to the review, PAC content in cranberry products is important because PACs are what prevents bacteria from sticking to the bladder walls, but there is no established dosage of PACs and no formal regulation by health authorities of cranberry products. This creates inconsistency in the marketplace, with some products not even listing suggested doses on the packaging.
"The meta-analysis stresses the importance of utilizing cranberry products standardized for PAC content,” said Amy Howell, PhD, in a statement released by The Cranberry Institute. Howell is an Associate Research Scientist (Emeritis) at the Marucci Center for Blueberry Cranberry Research at Rutgers University and has extensively researched the effects of cranberry products on the management of bacterial diseases such as UTIs. Howell explains that the PACs in cranberry products can help reduce one’s dependence on antibiotics, lessening the opportunity for antibiotic resistance and making them more effective in the future when needed.
"After many years of research studying the health effects of cranberries, I am confident the results of the Cochrane Review will provide healthcare professionals and consumers with the clinical validation they need to recommend and utilize cranberry products for prevention of recurrent UTIs," said Howell. "Daily cranberry intake could potentially lead to a reduction in UTIs, meaning better quality of life and reduced hospitalizations and complications that can result from these infections."