Can Cranberry’s Bioactive Ingredient Prevent UTIs?

By: Brian J. Flynn, MD

The urgent battle against recurrent UTIs and antibiotic resistance requires a fresh look at cranberries for UTI prevention.

Recurrent urinary tract infections ( UTIs) have a large impact on patients’ quality of life. They account for some 10 million office visits a year and up to 60% of all antibiotic prescriptions.A frustrating “revolving door” of appointments often includes a treat-and-repeat cycle of antibiotics. Perimenopausal women suffer the most from recurrent UTIs, and these troublesome infections can lead to more serious medical problems.

Antibiotic Overuse

At least 30% of outpatient antibiotic prescriptions in the United States are not needed, according to the Centers for Disease Control and Prevention.

Global health agencies have asked healthcare providers to curb antibiotic use in light of the widespread concerns over side effects and antibiotic resistance. Resistance occurs when the bacteria is stronger than the antibiotics. Drug-resistant rates for the most common UTI-associated bacteria E coli, for example, are rising at an alarming rate.

Managing Patients with UTIs

Healthcare providers look to current evidence and expert guidelines to manage recurrent UTIs. We aim to limit unnecessary antibiotics, prescribing them only for patients with culture-proven infections. But, this may be confusing for patients who expect to receive an antibiotic when they have UTI-like symptoms.

The growing interest from healthcare providers in cranberry supplements as a non-antibiotic modality for the prevention of recurrent UTIs has taken center stage. This is an attempt to curb antibiotic prescribing and offers patients a proven alternative that poses little risk.

In its recent UTI guidelines, the American Urological Association states that “clinicians may offer cranberry prophylaxis for women with [recurrent] UTIs.” It is the only non-pharmaceutical recommendation included in the report.

They go on to highlight that an increasing number of randomized clinical trials have studied cranberry in a variety of formulations. This includes juice and tablets. The benefit is thought to be related to the bioactive proanthocyanidins (PAC) compounds and their role in preventing bacterial adhesion to the urinary tract wall.

More specifically, cranberry was associated with decreased risk of experiencing at least one UTI recurrence than placebo or no cranberry in five trials

Additionally, eight randomized trials of cranberry versus placebo/no cranberry (6 randomized controlled trials [RCTs], one with a lactobacillus arm) and cranberry versus antibiotics (2 RCTs) were referenced to support its use for UTI prophylaxis. Furthermore, researchers noted that in one trial cranberry was associated with a lower risk of resistance in E. coli than antibiotics, trimethoprim, and sulfamethoxazole.

The guidelines continue, stating that “there is little risk to cranberry supplements, further increasing their appeal to patients. However, it must be noted that fruit juices can be high in sugar content, which is a consideration that may limit use in diabetic patients.”

Important to note is that the guidelines state that the natural PAC compounds associated with bioactivity are found in varying concentrations depending on the formulation used. And that many products are explicitly developed for research purposes only. It is, therefore, necessary for healthcare providers to discuss the availability of the proper product with patients.

I recommend cranberry prophylaxis to my patients in the form of a once-daily medical-grade supplement containing 36 milligrams (mg) of bioactive PAC from cranberry.

The most important take away from these guidelines is that healthcare providers have an alternative preventive option to effectively manage recurrent UTIs. But they must do their homework to identify the appropriate PAC product that meets established criteria for efficacy.

With an understanding of the mechanism of action and a clear window into a PAC product’s bioactive formulation, its manufacturing process, and its content, this approach could be a welcome alternative to ongoing antibiotic use perpetuating a cycle of “treat and repeat”.

Ingredients Matter to Realize the Benefits of Cranberry.

For centuries, cranberry has been thought to benefit urinary tract health. However, evidence on how and why has been limited.

Research now confirms that a minimum of 36 mg of bioactive PAC extracted from the pure juice concentrate prevents UTI-causing bacteria from attaching to the bladder wall. This feature is called bacterial anti-adhesion activity or AAA.

Is It Soluble?

Science supports this powerful high-dose of bioactive PAC. It is important to note, however, only the soluble type of PAC has maximum AAA and is powerful enough to reduce recurrent UTIs. This type of PAC is found mostly in pure cranberry concentrate and not the whole berry. Local grocery stores or pharmacies offer products that vary widely in their ingredients making them unreliable and ineffective.

In fact, many contain less than 5 mg of PAC and minimal AAA. This is insufficient for UTI prevention.

These supplements are often inexpensively made from the juicing leftovers like dried skins, stems, and seeds. Some supplements may include sugar or added ingredients that fuel the UTI fire. These may be inappropriate in diabetes patients or those with other medical conditions.

Product Considerations in Unregulated Market

The Food and Drug Administration FDA does not require manufacturers to prove claims and labeling for supplements. This means it is crucial for providers and patients to carefully review product ingredients.

To be effective, a formula must contain 36 mg bioactive PAC extracted from pure juice. In a clinical study, one supplement with 36 mg of soluble PAC was as effective a low-dose antibiotic for preventing UTIs. The same supplement prevented UTIs in catheter users, without the side effects and resistance associated with antibiotics.

Proactive UTI Prevention

The urgent battle against recurrent UTIs and antibiotic resistance requires a fresh look at cranberry for UTI prevention. The benefits of 36 mg PAC provide an opportunity to broaden the conversation with UTI sufferers. Healthcare providers can inform patients that antibiotics must only be used when absolutely necessary and discouraged as a preventive option.

Proper self-care -drinking more water, urinating after intercourse, and wiping front to back-should not be overlooked. When those behavioral options are not enough, we now have a proven alternative solution.

Related Content: Holistic Preventive Medicine Can Change Your Life for the Better


I focus on a proactive approach to recurrent UTI prevention, recommending a medical-grade supplement with the clinically proven dose of 36 mg bioactive PAC. This approach empowers patients to prevent recurrent UTIs naturally and with confidence.



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Brian J. Flynn, MD is the Co-Director of Female Pelvic Medicine and Reconstructive Surgery at the University of Colorado School Hospital and is a Professor of Surgery/Urology. He received his Bachelor of Science Degree in Electrical Engineering from the University of Rochester, Rochester, New York, Doctorate of Medicine from Temple University School of Medicine, Philadelphia, Pennsylvania, residency in Urology at Geisinger Medical Center, Danville, Pennsylvania and fellow from Duke University. Dr. Flynn is a consultant to Trophikos.

Originally published at on June 23, 2019.

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