Cranberry Juice Does Not Prevent Urinary Tract Infection, New Study Finds


Cranberry juice and tablets have been recommended as a way to either prevent recurring urinary tract infection (UTI), or treat the symptoms.  But a new study finds there’s no difference between people treated with cranberries or placebos.

A lack of evidence for cranberry juice or capsules as being an effective preventative measure or treatment has been a recurring argument in the scientific literature for years now.

Cranberry Juice – An Unrealistic Recommendation for UTIs

A urinary tract infection occurs when bacteria gets into your urine and travels up to your bladder.  According to the Urinary Care Foundation, “UTIs cause more than 8.1 million visits to health care providers each year. About 10 in 25 women and 3 in 25 men will have symptoms of at least [one] UTI during their lifetime.”

For years now, cranberry juice has been recommended to aid in preventing or treating UTIs.  However, there’s no solid evidence that any amount is having a positive effect.

Additionally, based on the results of a recent study led by infectious disease specialist Manisha Juthani-Mehta from the Yale School of Medicine, even if you switch to highly concentrated capsules, you still don’t see a noticeable positive effect.

In response to this recent study, Lindsay E. Nicolle, an expert on UTIs from the University of Manitoba advises the following:

“The continuing promotion of cranberry use to prevent recurrent UTI in the popular press or online advice seems inconsistent with the reality of repeated negative studies or positive studies compromised by methodological shortcomings.”

Nicolle adds, “[C]linicians should not be promoting cranberry use by suggesting that there is proven, or even possible benefit.  Any continued promotion of the use of cranberry products seems to go beyond available scientific evidence and rational reasoning. It is time to move on from cranberries.”

Myth versus Facts

There’s a couple of reasons why the myth that cranberry juice is beneficial in preventing and treating UTIs has persisted for so long.

First, the active ingredient in cranberries — A-type proanthocyanidins (PACs) — has been shown to block the adhesion of bacteria to the wall of the bladder.  So, a vast majority of people have reasoned that if bacteria are causing UTIs, something that blocks bacteria from accumulating in the bladder could be a potential preventive or treatment measure.

But, according to Timothy Boone, M.D., Ph.D., vice dean of the Texas A&M Health Science Center College of Medicine Houston campus and chairperson of the department of urology for Houston Methodist Hospital, there’s one problem.

“Cranberry juice, especially the juice concentrates you find at the grocery store, will not treat a UTI or bladder infection,  It can offer more hydration and possibly wash bacteria from your body more effectively, but the active ingredient in cranberry is long-gone by the time it reaches your bladder.”

Dr. Boone adds, “It takes an extremely large concentration of cranberry to prevent bacterial adhesion.  This amount of concentration is not found in the juices we drink. There’s a possibility it was stronger back in our grandparents’ day, but definitely not in modern times.”

For example, Ocean Spray’s cranberry juice cocktail is only 27 percent juice.  Something so watered down could not be so ineffective.

The second reason the myth continues is that it’s a tempting myth to believe. If you experience recurring UTIs and want to prevent them — or you want to feel empowered while you’re waiting for the antibiotics to take effect — drinking cranberry juice or taking capsules is a fairly easy and simple way to feel like you’re helping resolve your problem.

Unfortunately, though, you’re paying a lot of money for something that’s only really doing the same job as a glass of water.  And cranberry juice is full of sugar anyway.

Golden Rules for Kidney Health

You can do a number of things to help keep your kidneys functioning properly at every stage of life.

Here’s a list of ways to reduce the risk of kidney disease – including urinary tract infections.

  • Drink plenty of liquids, especially water. Drinking water helps dilute your urine and ensures that you’ll urinate more frequently — allowing bacteria to be flushed from your urinary tract before an infection can begin.
  • Stay active and keep fit. Keeping fit helps to reduce your blood pressure.  Staying active and keeping fit also reduces the risk of chronic kidney disease.
  • Eat healthy and keep your weight in check. This can help prevent diabetes, heart disease, and other debilitating conditions associated with chronic kidney disease.
  • Reduce your salt intake. The recommended sodium intake is 5-6 grams of salt per day — around a teaspoon. Try limiting the amount of processed and restaurant food.  And don’t add salt to food. It’s easier to control your salt intake if you prepare the food yourself with fresh ingredients.
  • Don’t take over-the-counter pills on a regular basis. Common non-steroidal anti-inflammatory drugs — like ibuprofen — are known to cause kidney damage and disease if taken regularly.  This type of medication probably doesn’t pose considerable danger if your kidneys are reasonably healthy and you use them for emergencies only.  However, if you are dealing with chronic pain — like back pain or arthritis — work with your doctor to find natural ways to control your pain without putting your kidneys at risk.
  • Wipe from front to back. Doing so after urinating and after a bowel movement helps prevent bacteria in the anal region from spreading to the vagina and urethra.
  • Change your birth control method. Diaphragms, or unlubricated or spermicide-treated condoms, can all contribute to bacterial growth.
  • Avoid potentially irritating feminine products. Using deodorant sprays or other feminine products, such as douches and powders, in the genital area can irritate the urethra.
  • Empty your bladder soon after intercourse. Also, drink a full glass of water to help flush bacteria.
  • Regularly control of your blood sugar level. About half of people who have diabetes develop kidney damage, so it is important for people with diabetes to have regular tests to check their kidney functions.

This recent randomized clinical trial study titled, “Effect of Cranberry Capsules on Bacteriuria Plus Pyuria Among Older Women in Nursing Homes,” is published in the Journal of the American Medical Association.

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George Zapo, CPH
George Zapo, CPH is certified in Public Health Promotion & Education. George focuses on writing informative articles promoting healthy behavior and lifestyles. Read more of George's articles at his website: