Drinking up to 300 mL per day of cranberry juice for six months was also associated with a 34% reduction in the need for antibiotics, report Finnish researchers in Clinical Infectious Diseases.
“UTIs are one of the most common bacterial infections in pediatric medicine and children with recurrent problems often face long-term antibiotic use,” said Dr Tero Kontiokari of the University of Oulu in Finland and co-researcher on the study.
“The cranberry is well known for preventing urinary tract infections in adult women, but this study shows that cranberry juice can be effective also among children in reducing the number of recurrences in children with multiple UTIs.”
The double-blind randomized placebo-controlled trial adds to the extensive body of evidence supporting the benefits of cranberries and the compounds they contain for urinary tract health.
In 2004 France became the first country to approve a health claim for the North American cranberry (Vaccinium macrocarpon) with at least 36mg of proanthocyanidins (PAC) to “help reduce the adhesion of certain E. coli bacteria to the urinary tract walls”, and subsequently fight UTIs, a condition that will affect over 50 percent of women at least once in their lifetime.
PACs are not exclusive to cranberries, and can be found in a range of foods, including green tea, grapes, apples, and chocolate. However, the main type of PACs in cranberry called A-type PACs are different from those in these other sources, called B-type PACs. Only cranberry PACs may prevent bacterial adhesion.
The French health claim refers to 36 milligrams of PACs measured using the 4-dimethylaminocinnamaldehyde (DMAC) method. Three hundred milliliters of cranberry juice provides 36 mg proanthocyanidins.
Benefits for kids, too
The potential urinary tract benefits of the berry appear to also extend to children, according to the new study’s results. The Finnish researchers recruited 255 children treated for UTI and randomly assigned them to receive either cranberry juice or placebo for 6 months.
Results showed that, during one year of study, 16 % of the cranberry group and 22% of the placebo group experienced at least one recurrent UTI.
There were 27 UTI episodes in the cranberry group, compared with 47 episodes in the placebo group, added the researchers.
“Cranberry products are thought to act against uropathogenic bacteria – mostly E. coli – by inhibiting their growth and p-pili–mediated adhesion and possibly by reducing their biofilm production,” they said.
“It may be that this effect does not happen in the urinary tract but in the gut. The selection pressure created in the stool by the presence of cranberry residues may induce a shift toward a less uropathogenic bacterial flora, and hence prolonged protection against UTI.
“Taking account of the relatively innocent nature of UTI recurrences in children who do not have marked urinary tract pathology, cranberry juice seems to offer an alternative to antimicrobials for preventing UTIs in children who are susceptible to recurrences.”
The study was welcomed by Christina Khoo, senior manager of research sciences at cranberry giant Ocean Spray. “This study shows that cranberry juice could potentially help reduce use of antibiotics in children who are susceptible to UTI recurrences,” she said.
“Antibiotic use for UTI treatment is a major contributor to the growth of antibiotic resistance. Research continues to emerge to highlight the whole body health benefits of the cranberry and we will support further work to improve our understanding.”
Source: Clinical Infectious Diseases
2012, Volume 54, Number 3, Pages 340-346, doi: 10.1093/cid/cir801
“Cranberry Juice for the Prevention of Recurrences of Urinary Tract Infections in Children: A Randomized Placebo-Controlled Trial”
Authors: J. Salo, M. Uhari, M. Helminen, M. Korppi, T. Nieminen, T. Pokka, T. Kontiokari