Abstract: FRI-10
Sources of Funding: none

Introduction

The public has long considered cranberry juice to contain properties that prevent urinary tract infections (UTI), a common enough conception that it has been explored repeatedly by scientific bodies. This work highlights the history of the medical opinion regarding the role of cranberries in UTI prevention.

Methods

A literature search including Pubmed and domestic periodicals was performed.

Results

Cranberries were first thought to have medicinal qualities by Native Americans, and their plant leaves used for urinary and gastrointestinal disorders. As early as the 1920s, the scientific community reported that cranberry consumption contributed to the acidification of urine, and over the next decade, this was found to be a result of excreted hippuric acid. Until the 1970s, acidification of the urine was considered to be the utility of cranberries in the prevention of UTIs. Studies aiming to confirm this theory showed no or only a transient effect and new theories were sought. After the discovery of the importance of bacterial adherence in the pathogenesis of UTIs, several studies in the mid- and late-1980s suggested that cranberries prevent the adhesion of bacterial organisms, specifically E. Coli, to the uroepithelial cell walls. Over the next decade, fructose and proanthocyanidins were identified as the &[Prime]active&[Prime] components that exhibit this anti-adhesion property. In the last twenty years, multiple randomized-control and quasi-randomized control studies investigated the effectiveness of cranberry juice, syrups, powders, capsules and tablets in preventing UTIs. An article published in 2000 and sponsored by Ocean Spray Cranberries, Inc. presented a multitude of studies that suggest that regular consumption of cranberry juice cocktail reduces the risk of UTIs and inhibits bacterial adherence to mucosal surfaces. Cochrane reviews in 2000, 1998, 2004, and 2008 evaluated these studies and furthered the notion that there may be a decrease in symptomatic UTIs in women with recurrent infections over a 12-month period. However, the most recent update in 2012, which included 24 studies (14 more than 2008) and 4,473 participants suggested no statistically significant benefit in any high-risk group. Most recently, a study in JAMA found no benefit among women living in nursing homes.

Conclusions

While a mechanism by which cranberry consumption may theoretically prevent UTIs has been proposed, and some research has suggested a benefit, a lack of strong evidence has left the most current medical opinion unable to justify proactive physician support of the practice.

Funding

none