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Cranberry juice for UTIs: natural remedy or old wives’ tale?

A few trials have looked at this topic, but they've been fairly small. This large randomized trial looked at cranberry juice for women with recurrent UTIs.

Study under review: Consumption of a cranberry juice beverage lowered the number of clinical urinary tract infection episodes in women with a recent history of urinary tract infection

Introduction

Nearly two out of every three women will experience at least one[1] urinary tract infection (UTI) in their lifetime. Of these, about one-fourth[2] will have a recurrent UTI within six months of the initial treatment, and one-third to one-half[3] will have a recurrent UTI within one year. Over 11 million women seek antibiotic treatment for UTIs each year.

Cranberry juice and cranberry supplements have previously been recommended for preventing and/or treating UTIs, as cranberries are rich in potentially helpful phenolic compounds[4]. Many plant phenols, such as flavonoids (shown in Figure 1) and tannins, have been investigated[5] for therapeutic or medicinal properties, including antioxidant and anti-inflammatory effects.

The evidence for the beneficial effects of cranberry juice on UTIs is mixed, however. A prior meta-analysis[6] found a small but positive effect of cranberry juice products on UTI incidence, but many[7] individual[8] studies have failed to show a positive effect of cranberry juice consumption on UTIs. However, there has been some concern[9] that studies were underpowered, because the incidence of UTIs during the study period ended up being lower than the statistical design had planned for. In addition, it’s possible that certain populations who are at higher risk for recurrence may experience more benefit than the general population. This study aimed to evaluate only those women who were at a risk for recurrent UTIs.

Urinary tract infections are a common occurrence among women, with nearly two-thirds of women experiencing at least one UTI and over one-fourth suffering from recurrent UTIs. Cranberry juice is often recommended to treat or prevent UTIs, but the research supporting this recommendation has been mixed to date.

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