From the Guidelines
Cranberry products, specifically those containing proanthocyanidin levels of 36 mg, may be recommended to prevent recurrent urinary tract infections (UTIs) in women, children, and individuals susceptible to UTIs, as they can reduce the risk of UTIs. The active compounds in cranberries, called proanthocyanidins (PACs), make it difficult for bacteria to attach to the urinary tract walls, allowing them to be flushed out during urination 1. For prevention, consuming cranberry products containing 36 mg of PACs may be beneficial. It is essential to note that cranberry products work best as a preventive measure for those with recurrent UTIs rather than as a treatment for active infections.
Key Considerations
- Cranberry products are generally safe but may interact with blood thinners like warfarin and can increase the risk of kidney stones in susceptible individuals.
- The evidence for the use of cranberry products in older adults, those with bladder emptying problems, or pregnant women is insufficient 1.
- Cranberry juice cocktails with added sugars may provide less benefit than pure cranberry juice or supplements.
- For active UTI treatment, antibiotics prescribed by a healthcare provider remain the standard of care, as cranberry alone is insufficient to clear an established infection.
Prevention Strategies
- Cranberry products containing proanthocyanidin levels of 36 mg may be recommended to prevent recurrent UTIs.
- Increased water intake, specifically an additional 1.5L of water, may also decrease UTIs in healthy women 1.
- Vaginal estrogen, such as vaginal rings, vaginal insert, or vaginal cream, may be recommended for prevention, but availability may vary in different countries or geographic regions 1.
- Methenamine hippurate, 1 g twice daily, may be an appealing antimicrobial-sparing intervention to reduce UTIs in patients without incontinence and a fully functional bladder 1.
From the Research
Effect of Cranberry on Urinary Tract
- Cranberry products have been extensively evaluated for the management of urinary tract infections (UTIs) 2, 3, 4, 5, 6
- The focus has been on the use of cranberry as a preventative strategy, as there is no evidence that it can be used to treat UTIs 2
- Cranberry appears to work by inhibiting the adhesion of type I and P-fimbriated uropathogens to the uroepithelium, thus impairing colonization and subsequent infection 2, 3, 6
- The anthocyanidin/proanthocyanidin moieties are believed to be the potent antiadhesion compounds in cranberry 2, 3, 6
Efficacy of Cranberry in Preventing UTIs
- Meta-analyses have established that recurrence rates over 1 year are reduced approximately 35% in young to middle-aged women 2
- The efficacy of cranberry in other groups, such as the elderly, pediatric patients, and those with neurogenic bladder or chronic indwelling urinary catheters, is questionable 2
- A systematic review with meta-analysis and trial sequential analysis of clinical trials found that cranberry products significantly reduced the incidence of UTIs 4
- Subgroup analysis demonstrated that patients at some risk for UTIs were more susceptible to the effects of cranberry ingestion 4
Safety and Potential Interactions
- Adverse events associated with cranberry products include gastrointestinal intolerance, weight gain, and drug-cranberry interactions 2
- The use of cranberry products appears to be safe and may provide additional benefits, such as anti-oxidant and cholesterol-lowering activity 3
- A study investigated the potential interaction between cranberry juice and beta-lactam antibiotics, and found that cranberry juice in usual quantities as prophylaxis for UTI is not likely to alter the pharmacokinetics of these oral antibiotics 6