Scottish researchers have shot down a popular home remedy believed to have infection-fighting properties. They concluded that cranberry juice is unlikely to prevent a urinary tract infection (UTI).
Scientists from the University of Stirling published their findings after reviewing the results of 24 studies involving 4,473 subjects, according to Medical News Today. They believe that if there is any benefit from drinking cranberry juice, it's probably small and affects only women who suffer from recurrent bouts of these infections.
Prior studies have questioned whether this juice is really effective at prevention. The Mayo Clinic says that one problem in assessing its value is that it's unclear how much a person would need to drink. However, for most people, there's probably no harm in drinking it.
Bacteria residing in the intestines is the most common cause of UTIs. An infection can travel from the bladder, up the ureters, and into the kidneys. According to the National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), UTIs are the second-most common type of human infection and are linked to 8.1 million visits to healthcare providers a year.
Around 1 in 5 young women who experience a UTI will have a recurrent bout. With each episode, the risk of recurrent infections increases. The most typical pattern is a year or two of frequent infections, after which they cease, NKUDIC says.
The subjects the Scottish researchers followed were divided into two groups. The first received treatment as cranberry juice in capsules or tablets. The second group received placebo cranberry products, water, antibiotics, methenamine hippurate, lactobacillus, or nothing.
Some of the studies showed a small benefit to women who suffered from recurrent UTIs. However, to ward off just one outbreak, they needed to consume two glasses of cranberry juice a day for extended periods.
One problem is that studies that assessed the effectiveness of tablets or capsules have seldom reported the amount of active ingredient used. The Stirling researchers believe that as far as future studies go, the only useful ones would be those that assessed any benefits for women with recurrent infections and that specified the amount of active ingredient used.
While a college student, I experienced a year when my immune system seemed to go haywire. Years later, I attributed many trips to the student health service to what was eventually diagnosed as Crohn's disease. I experienced a series of UTIs that year. I remember a nurse telling me to be sure to drink a big glass of cranberry juice every day to prevent future recurrences. When I went home for the summer, I left the illness behind.
If I actually liked the taste of cranberry juice, I'd drink it now and then. However, knowing it's unlikely to prevent urinary tract infections, I don't plan to put it on my grocery list.
Vonda J. Sines has published thousands of print and online health and medical articles. She specializes in diseases and other conditions that affect the quality of life.