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Urinary Tract Health and Antibacterial Benefits: Review

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Complementary, holistic, and integrative medicine: cranberry.

Posted
Authors
Shamseer L, Vohra S
Journal
Pediatr Rev 28 (8):e43-5
Abstract

No abstract - Introduction: Cranberry is among the most commonly used natural health products in North America. Commercial cranberry products commonly are derived from the Vaccinium oxycoccos and V macrocarpon species, which are cultivated widely across the Northern hemisphere. Seventy percent of the cranberry crop in North America is controlled by a single manufacturer. Historically, cranberry fruits and leaves have been used for wound dressings, urinary disorders, diabetes, blood poisoning, diarrhea, and liver problems. More recently, cranberry has been used to prevent urinary tract infections (UTIs) and dental plaque. The scientific evidence regarding medicinal uses of cranberry in pediatric populations is presented in this article.

Cranberries for preventing urinary tract infections

Posted
Authors
Jepson RG, Craig JC
Journal
Cochrane Database Syst Rev (1):CD001321
Abstract

BACKGROUND: Cranberries have been used widely for several decades for the prevention and treatment of urinary tract infections (UTIs).

OBJECTIVES: To assess the effectiveness of cranberry products in preventing UTIs in susceptible populations.

SEARCH STRATEGY: We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library) and the Internet. We contacted companies involved with the promotion and distribution of cranberry preparations and checked reference lists of review articles and relevant studies. Date of last search: January 2007.

SELECTION CRITERIA: All randomised controlled trials (RCTs) or quasi-RCTs of cranberry products for the prevention of UTIs in all populations.

DATA COLLECTION AND ANALYSIS: Two authors independently assessed and extracted information. Information was collected on methods, participants, interventions and outcomes (UTIs - symptomatic and asymptomatic, side effects, adherence to therapy). Relative risk (RR) were calculated where appropriate, otherwise a narrative synthesis was undertaken. Quality was assessed using the Cochrane criteria.

MAIN RESULTS: Ten studies (n = 1049, five cross-over, five parallel group) were included. Cranberry/cranberry-lingonberry juice versus placebo, juice or water was evaluated in seven studies, and cranberries tablets versus placebo in four studies (one study evaluated both juice and tablets). Cranberry products significantly reduced the incidence of UTIs at 12 months (RR 0.65, 95% CI 0.46 to 0.90) compared with placebo/control. Cranberry products were more effective reducing the incidence of UTIs in women with recurrent UTIs, than elderly men and women or people requiring catheterisation. Six studies were not included in the meta-analyses due to methodological issues or lack of available data. However, only one reported a significant result for the outcome of symptomatic UTIs. Side effects were common in all studies, and dropouts/withdrawals in several of the studies were high.

AUTHORS' CONCLUSIONS: There is some evidence that cranberry juice may decrease the number of symptomatic UTIs over a 12 month period, particularly for women with recurrent UTIs. It's effectiveness for other groups is less certain. The large number of dropouts/withdrawals indicates that cranberry juice may not be acceptable over long periods of time. It is not clear what is the optimum dosage or method of administration (e.g. juice, tablets or capsules). Further properly designed studies with relevant outcomes are needed.

Cranberry and urinary tract infections

Posted
Authors
Guay DR
Journal
Drugs 69(7):775-807
Abstract

Urinary tract infection (UTI) refers to the presence of clinical signs and symptoms arising from the genitourinary tract plus the presence of one or more micro-organisms in the urine exceeding a threshold value for significance (ranges from 102 to 103 colony-forming units/mL). Infections are localized to the bladder (cystitis), renal parenchyma (pyelonephritis) or prostate (acute or chronic bacterial prostatitis). Single UTI episodes are very common, especially in adult women where there is a 50-fold predominance compared with adult men. In addition, recurrent UTIs are also common, occurring in up to one-third of women after first-episode UTIs. Recurrences requiring intervention are usually defined as two or more episodes over 6 months or three or more episodes over 1 year (this definition applies only to young women with acute uncomplicated UTIs). A cornerstone of prevention of UTI recurrence has been the use of low-dose once-daily or post-coital antimicrobials; however, much interest has surrounded non-antimicrobial-based approaches undergoing investigation such as use of probiotics, vaccines, oligosaccharide inhibitors of bacterial adherence and colonization, and bacterial interference with immunoreactive extracts of Escherichia coli. Local (intravaginal) estrogen therapy has had mixed results to date. Cranberry products in a variety of formulations have also undergone extensive evaluation over several decades in the management of UTIs. At present, there is no evidence that cranberry can be used to treat UTIs. Hence, the focus has been on its use as a preventative strategy. Cranberry has been effective in vitro and in vivo in animals for the prevention of UTI. Cranberry appears to work by inhibiting the adhesion of type I and P-fimbriated uropathogens (e.g. uropathogenic E. coli) to the uroepithelium, thus impairing colonization and subsequent infection. The isolation of the component(s) of cranberry with this activity has been a daunting task, considering the hundreds of compounds found in the fruit and its juice derivatives. Reasonable evidence suggests that the anthocyanidin/proanthocyanidin moieties are potent antiadhesion compounds. However, problems still exist with standardization of cranberry products, which makes it extremely difficult to compare products or extrapolate results. Unfortunately, most clinical trials have had design deficiencies and none have evaluated specific key cranberry-derived compounds considered likely to be active moieties (e.g. proanthocyanidins). In general, the preventive efficacy of cranberry has been variable and modest at best. Meta-analyses have established that recurrence rates over 1 year are reduced approximately 35% in young to middle-aged women. The efficacy of cranberry in other groups (i.e. elderly, paediatric patients, those with neurogenic bladder, those with chronic indwelling urinary catheters) is questionable. Withdrawal rates have been quite high (up to 55%), suggesting that these products may not be acceptable over long periods. Adverse events include gastrointestinal intolerance, weight gain (due to the excessive calorie load) and drug-cranberry interactions (due to the inhibitory effect of flavonoids on cytochrome P450-mediated drug metabolism). The findings of the Cochrane Collaboration support the potential use of cranberry products in the prophylaxis of recurrent UTIs in young and middle-aged women. However, in light of the heterogeneity of clinical study designs and the lack of consensus regarding the dosage regimen and formulation to use, cranberry products cannot be recommended for the prophylaxis of recurrent UTIs at this time.

Recurrent urinary tract infections in older people: the role of cranberry products

Posted
Authors
Sumukadas D, Davey P and McMurdo ME
Journal
Age Ageing 38(3):255-7
Abstract

No abstract - Introduction: Urinary tract infections (UTI) are the commonest bacterial infection in older people. Half of all women experience at least one UTI and the risk increases with age. The present management of recurrent urinary tract infection is prophylaxis with low-dose, long-term antibiotics. However, there is a growing reluctance to prescribe antibiotics unless absolutely essential because of fears about antimicrobial resistance. So the recent resurgence in interest in the potential role of cranberry
products is timely.

Cranberry is not effective for the prevention or treatment of urinary tract infections in individuals with spinal cord injury.

Posted
Authors
Opperman EA
Journal
Spinal Cord 48(6):451-6
Abstract

STUDY DESIGN: Literature review. OBJECTIVES: Urinary tract infections (UTIs) are the most common medical complication experienced by individuals with spinal cord injury (SCI). Recent research presents conflicting evidence regarding use of cranberry in reducing growth and colonization of uroepithelial cells by uropathogenic bacteria. The objective was to determine whether the literature supports the use of cranberry in preventing or treating UTIs in the SCI population. METHODS: MEDLINE was searched for intervention studies, which investigated the use of cranberry in the prevention or treatment of UTIs in the SCI population. If the studies met the inclusion criteria, full articles were located and reviewed. RESULTS: Five studies (four randomized clinical control-three trials using cranberry tablets vs placebos and one using cranberry juice-and one pilot study using cranberry juice) were identified which evaluated the effectiveness of cranberry products for the prevention or treatment of UTIs in the SCI population. Three studies reported no statistically significant effect of cranberry tablets in urinary pH, urinary bacterial count, urinary white blood cell (WBC) count, urinary bacterial, and WBC counts in combination or episodes of symptomatic UTIs. A fourth study showed that cranberry juice intake significantly reduced biofilm load compared with baseline. A final study reported fewer UTIs during the period with cranberry extract tablets vs placebo. CONCLUSIONS: Limited evidence from clinical trials that vary in design suggests that cranberry, in juice or supplement form, does not seem to be effective in preventing or treating UTIs in the SCI population. More rigorous clinical research is needed to confirm this.

Cranberry juice and urinary tract infections: is there a beneficial relationship

Posted
Authors
Kuzminski LN
Journal
Nutr Rev 54(11 Pt 2):S87-90
Abstract

No abstract - Conclusion:
Science often causes us to disregard the validity of folklore
treatments for common medical conditions. However,
those folklore practices that retain a persistent consumer
and practitioner following over time merit rigorous scientific scrutiny. Approaches such as those described here
regarding UTI risk reduction by cranberry juice could serve
as a model to clarify the potential functional food role of
Cranberry juice in treating and preventing UTIs.

Cranberry juice for prophylaxis of urinary tract infections – conclusions from clinical experience and research

Posted
Authors
Nowack R, Schmidt W
Journal
Phytomedicine 15(9):653-667
Abstract

Cranberry juice (Vaccinium macrocarpon) is a widely used and recommended North-American folk remedy for prophylaxis of urinary tract infections (UTI). Clinical trials have documented its efficacy in women with recurrent UTI, but so far not in other groups of patients. The composition of effective cranberry products and its dosage in UTI prophylaxis have not been defined. Intriguing experimental research has identified an anti-adhesive mechanism of cranberry juice that prevents docking of bacteria on host tissues. This efficacy mechanism can be traced in patients' urine following oral intake of cranberry products and appears to be due to proanthocyanidins with an A-type linkage of flavanols. The application of this anti-adhesion mechanism of cranberry-proanthocyandins is currently also investigated in other common diseases of bacterial pathogenesis, for example Helicobacter pylori-associated gastritis and dental caries/periodontal disease. The use of cranberry products appears to be safe and provide additional benefits by anti-oxidant and cholesterol-lowering activity.