Are High Proanthocyanidins Key to Cranberry Efficacy in the Prevention of Recurrent Urinary Tract Infection?

Abstract

Most research on American cranberry in the prevention of urinary tract infection (UTI) has used juices. The spectrum of components in juice is limited. This study tested whether whole cranberry fruit powder (proanthocyanidin content 0.56%) could prevent recurrent UTI in 182 women with two or more UTI episodes in the last year. Participants were randomized to a cranberry (n = 89) or a placebo group (n = 93) and received daily 500 mg of cranberry for 6 months. The number of UTI diagnoses was counted. The intent-to-treat analyses showed that in the cranberry group, the UTIs were significantly fewer [10.8% vs. 25.8%, p = 0.04, with an age-standardized 12-month UTI history (p = 0.01)]. The Kaplan-Meier survival curves showed that the cranberry group experienced a longer time to first UTI than the placebo group (p = 0.04). Biochemical parameters were normal, and there was no significant difference in urinary phenolics between the groups at baseline or on day180. The results show that cranberry fruit powder (peel, seeds, pulp) may reduce the risk of symptomatic UTI in women with a history of recurrent UTIs.

Natural therapeutics for urinary tract infections—a review

“…P-fimbriated UPEC isolation was 43.5% (10 of 23) in cranberry juice group, 80.0% (8 of 10) in placebo group during the study period [ 107 ] Randomized, double-blind, placebo-controlled trial 3 capsules of PAC daily for 30 days (108 mg, 72 mg, 36 mg) 80 women Dose-dependent reduction in bacteriuria and pyuria [ 108 ] Modified observational study Sweetened dried cranberry (SDC) of one serving daily for 14 days 20 women with recurrent UTIs Mean UTI rate per six months decreased significantly, no UTI observed in > 50% of the patients up to 6 months of SDC consumption [ 109 ] Randomized, double-blind, placebo-controlled multicenter trial Capsules of cranberry and placebo were taken twice daily for 1 year 928 women of high and low risk group Incidence of UTI reduced in cranberry than placebo group (62.8 vs 84.8 per 100 person-years in UTI high risk group). No difference observed in low UTI risk group [ 110 ] Randomized, double-blind, placebo-controlled trial Two cranberry juice capsules twice daily for 6 weeks or placebo 160 women undergoing gynecological surgery involving urinary catheterization (80 + 80) 19% UTI incidence in cranberry group compared to 38% in placebo group [ 111 , 112 ] Randomized, double-blind, placebo-controlled trial 500 mg of whole cranberry fruit powder for 6 months or placebo Cranberry ( n = 89) or a placebo group ( n = 93) UTI occurrence significantly lowered 10.8% vs 25.8% in cranberry and placebo group, respectively [ 113 ] Randomized, double-blind, placebo-controlled trial 240 ml of cranberry juice per day for 24 weeks or placebo Cranberry ( n = 185) or a placebo ( n = 188) UTI occurrence significantly lowered 21% vs 36% in cranberry and placebo group, respectively [ 114 ] …”

Proanthocyanidins and hydrolysable tannins: occurrence, dietary intake and pharmacological effects

“…Results showed significantly fewer UTIs in the cranberry group with respect to the control group (10.8% vs. 25.8% respectively). The treated group also showed a much longer latency period before developing a new UTI episode than the placebo group (Vostalova et al, ). It should be mentioned, however, that the ability of cranberry to prevent UTIs has been recently questioned (Jepson et al, ; Izzo et al, ).…”

Inhibitory effect of cranberry extract on periodontopathogenic biofilm: An integrative review

“…[ 21 ] This herbal medicine is responsible for inhibiting the adherence of Escherichia coli and other pathogens to the epithelial cells and for selecting bacteria with lower adhesion potential in the gastrointestinal tract, thereby reducing the formation of biofilms. [ 22 ] Its potential action on Gram-negative bacteria, therefore, generates possible discussions about the existence of inhibitory effects on periodontal bacteria, which are also associated with peri-implant disease.…”