Cranberry juice reduces UTIs – large study

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Cranberry juice consumption significantly reduced symptomatic urinary tract infections (UTIs), found a large multi-site clinical trial by Boston University.

Experts on infectious disease and urinary tract infections (UTIs) gathered recently in London to discuss the alarming state of antibiotic resistance, and presented findings from a landmark study that shows that cranberries can be a nutritional approach to reducing symptomatic UTIs, and as a result, may be a useful strategy to decrease worldwide use of antibiotics.

According to the study, drinking an 8-ounce (240 ml) glass of cranberry juice a day reduces symptomatic UTIs by nearly 40% in women with recurrent UTIs – reducing the burden of UTIs and reducing the antibiotic use associated with treating recurrent UTIs.

"Currently the primary approach to reducing symptomatic events of UTI is the use of chronic antibiotics for suppression, an approach associated with side effects and development of antibiotic resistance. This study shows that consuming one 8-ounce (240 ml) glass of cranberry juice a day reduces the number of times women suffer from repeat episodes of symptomatic UTI and avoids chronic suppressive antibiotics," said Dr Kalpana Gupta, infectious disease specialist and professor of medicine at Boston University's School of Medicine.

An author on the study Gupta believes that cranberries can help to reduce the worldwide use of antibiotics and significantly improve the quality of life for women who suffer from recurrent UTI symptoms.

The 24-week study of 373 women, conducted by researchers at Boston University, Biofortis Innovation Services (a division of Merieux Nutrisciences) and 18 clinical sites throughout the US and France, is the largest clinical trial of its kind examining the effects of cranberry juice consumption on UTIs.

Researchers set out to find whether recurrent (or repeat) UTI sufferers could be protected from repeat infections by drinking cranberry juice. Participants were all healthy women, with an average age of 40, who had experienced at least two UTIs within the past year. During the study, participants were randomly chosen to drink a daily dose of eight ounces (240 ml) of either cranberry juice or a "placebo" beverage without cranberries.

The rate of UTIs decreased significantly among the cranberry drinkers, with just 39 diagnoses during the six-month study compared with 67 in the placebo group.

Women with symptomatic UTIs experience all the discomforts of a UTI, such as a strong, persistent urge to urinate or a burning sensation when urinating, but may or may not test positive for a bacterial infection upon a consult with a physician. In many instances, women are treated with antibiotics for symptom relief whether bacteria is found or not. According to Gupta, the key to avoiding the situation altogether may very well lay with the cranberry. "The key to cranberry's benefit is consuming a glass daily to help avoid the infection altogether," said Gupta. "Most people wait to drink cranberry juice until they have a UTI, but once the symptoms start they'll likely need a course of antibiotics."

UTIs are among the most common bacterial infections in women worldwide. Up to 60% of all women suffer a UTI in their lifetime and up to 25% experience a recurrence within six months. Some 150m UTIs occur annually worldwide, according to the American Urological Association, resulting in $6bn in annual health care costs.

Antibiotics are usually the first line of treatment for urinary tract infections, and women who have frequent UTIs may be prescribed low-dose antibiotics. Unfortunately, chronic overuse of these drugs has increased antibiotic resistance at an alarming rate globally. So much in fact, that the World Health Organisation cites a 50% resistance rate to one of the most widely used antibiotics to treat UTIs.

Luckily, cranberries contain a unique combination of compounds including Type-A PACs (or proanthocyanidins) that prevent bacteria from sticking and causing infection. In addition to PACs, new studies have revealed a new class of compounds, xyloglucan oligosaccharides, which have similar anti-bacterial properties against E. coli as PACs. This means there are multiple, unique elements within cranberries working hard for your health.

These unique compounds can be found in a variety of products, including cranberry juice cocktail, 100% cranberry juice, light cranberry juice, dried cranberries and cranberry extract; however most of the research surrounding cranberries and UTIs has been conducted using juice.

According to Gupta, those who suffer from UTIs can feel confident that this nutritional approach is a potential solution.

Abstract
Background: Urinary tract infections (UTIs) are among the most common bacterial infections and are often treated with antibiotics. Concerns about multidrug-resistant uropathogens have pointed to the need for safe and effective UTI-prevention strategies such as cranberry consumption.
Objective: We assessed the effects of the consumption of a cranberry beverage on episodes of clinical UTIs.
Design: In this randomized, double-blind, placebo-controlled, multicenter clinical trial, women with a history of a recent UTI were assigned to consume one 240-mL serving of cranberry beverage/d (n = 185) or a placebo (n = 188) beverage for 24 wk. The primary outcome was the clinical UTI incidence density, which was defined as the total number of clinical UTI events (including multiple events per subject when applicable) per unit of observation time.
Results: The dates of the random assignment of the first subject and the last subject’s final visit were February 2013 and March 2015, respectively. The mean age was 40.9 y, and characteristics were similar in both groups. Compliance with study product consumption was 98%, and 86% of subjects completed the treatment period in both groups. There were 39 investigator-diagnosed episodes of clinical UTI in the cranberry group compared with 67 episodes in the placebo group (antibiotic use–adjusted incidence rate ratio: 0.61; 95% CI: 0.41, 0.91; P = 0.016). Clinical UTI with pyuria was also significantly reduced (incidence rate ratio: 0.63; 95% CI: 0.40, 0.97; P = 0.037). One clinical UTI event was prevented for every 3.2 woman-years (95% CI: 2.0, 13.1 woman-years) of the cranberry intervention. The time to UTI with culture positivity did not differ significantly between groups (HR: 0.97; 95% CI: 0.56, 1.67; P = 0.914).
Conclusion: The consumption of a cranberry juice beverage lowered the number of clinical UTI episodes in women with a recent history of UTI.

Authors
Kevin C Maki, Kerrie L Kaspar, Christina Khoo, Linda H Derrig, Arianne L Schild and Kalpana Gupta

Ocean Spray Health material American Journal of Clinical Nutrition abstract

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