Cranberries Prevent UTIs, What Do We Know?

August 17, 2023 (DocRed); – Antimicrobial resistance to so-called first-line drugs for the treatment of urinary tract infections (UTIs) has increased in several parts of the world, placing a burden on economies and health systems. Therefore, it seems reasonable to consider new strategies to treat these patients. Several reviews have been published with conflicting results on the efficacy of different non-antibiotic drugs (cranberry, D-mannose, NSAIDs, etc.) in preventing and/or treating UTIs.

Nearly half of all women will report at least one UTI in their lifetime, and one in three women will already have a symptomatic UTI by age 24 and be treated with antibiotics. In addition, one in three people will experience a recurrent urinary tract infection (rUTI), defined as two episodes within 6 months or 3 episodes within a year.

These UTIs occur especially, but not exclusively, in susceptible women and are a major source of patient morbidity and healthcare costs.³ Even when symptoms are completely relieved with first-line antimicrobial therapy, they usually appear within three months of initial infection.

There are different risk factors that increase the chance of developing a UTI in different age groups:

• premenopausal women
• The mother has a history of urinary tract infection
• intercourse and use of spermicide
• Changes in the bacterial flora.

How to solve urinary tract infection?

For the treatment of uncomplicated infections, the Infectious Diseases Society of America (IDSA) recommended in 2010 a five-day course of nitrofurantoin as first-line treatment. Other antibiotics such as trimethoprim-sulfamethoxazole are also prescribed.

However, antimicrobial resistance to these molecules has increased significantly in many countries, placing a heavy burden on the world’s health and economic systems.

As the efficacy of antibiotics continues to decline, it seems reasonable to consider new preventive strategies and alternative treatments for patients with UTIs.

Blueberry Products: State of the Art

They are extracted from the fruit BilberryHistorically used by North American Indians to treat infections.¹ They have been studied extensively for the prevention and treatment of urinary tract infections. The most common include juice and pills (or capsules) containing fruit extracts, but evidence for preventing UTIs is conflicting.

Even the consumption of dehydrated fruit itself is considered affordable and potentially preventive.Bilberries contain a variety of active ingredients, but several studies have shown that proanthocyanidins (PACs) and fructose are the main components that prevent bacterial adhesion, such as Escherichia coli to the urinary tract.

What does the recent literature say?

Several reviews have been published on the efficacy of different non-antibiotic drugs (D-mannose, NSAIDs, etc.) in preventing or treating UTIs. However, scientists from the School of Biomedical Sciences at the University of New South Wales in Australia developed a literature review that included stricter inclusion criteria.

Regardless of the measure of success, half of the cranberry trials reported a reduction in the number of urinary tract infections. Furthermore, the authors demonstrate that the effectiveness in preventing these infections is highly dependent on the concentration of the product (correlated with the bacterial concentration).

The review also found wide variation in cranberry and D-mannose concentrations across the clinical trials reviewed, although three of the There was a statistically significant difference in the time to road infection. . Control group.

effectiveness versus safety

Another important result is side effects. In particular, cranberry-based products appeared to have the least impact. The main side effects are:

• Minor gastrointestinal problems (constipation, heartburn, loose stools)
• Vagina (itching, dryness)
• Migraine.

Complaints about a bitter taste were also found, as cranberry juice is often acidic (pH < 2.5), which (regardless of efficacy) is unpleasant for some patients, even with sweeteners.

In summary

Different reviews, with or without meta-analysis, have examined the effectiveness of cranberry products in treating and/or preventing UTIs, reporting conflicting results (approximately 50% of trials showed efficacy, the other 50% showed no effect) . ), which, in layman’s terms, is equivalent to flipping a coin.

This may be due to methodological flaws, such as small sample sizes, which meant that the studies were underpowered to detect differences between treatment groups, and that the products were not necessarily ineffective.

Most of the available evidence is inconclusive, as about half of the reviewed trials were successful, including a variety of factors including poor study design. This makes it difficult to recommend blueberry-based products. Future reviews should further investigate the efficacy and safety of these treatments with larger studies.