You've probably heard that drinking cranberry juice helps fight urinary tract infections. Maybe you've even chugged some yourself to help keep things in the clear. The idea is based in the science that cranberries contain compounds that are thought to prevent bacteria from sticking to the cells that line the bladder, so juice-makers like to tell us that cranberry juice helps prevent UTIs.
In reality, cranberry juice is not definitively proven to prevent UTIs, but companies love spending money to convince us that it does.
As Vox reports, juice companies fund studies saying cranberry juice can prevent UTIs. A new study, funded by Ocean Spray, concluded that "cranberries can be a nutritional approach to reducing symptomatic [urinary tract infections]."
What researchers aren't shouting from the rooftops is that the study was actually co-authored by Ocean Spray staff scientists. Hardly an unbiased party. Other reviews and studies have found no connection between UTI prevention and juice, likely because most juices are primarily water and concentrate. That means that the juice doesn't contain enough of the compounds in actual cranberries to make a difference in treating your UTI.
How do the companies game the system? By being focused on a much broader definition of what a UTI is, Vox reports. Instead of looking at the urine test that finds higher-than-normal levels of bacteria (you know this well if you get regular UTIs), the researchers focused their findings on women who simply complained of UTI symptoms and didn’t actually have a positive urine culture.
With a control group (drinking sugar water) and another group of women, there was a difference. And it did favour drinking cranberry juice: There were 39 episodes of symptomatic UTIs in the cranberry group compared with 67 episodes in the placebo group.
"They made [cranberry juice] appear much more effective by using a clinical definition — symptoms — which is rubbery at best," Jonathan Craig, a clinical epidemiology professor at the University of Sydney, told Vox. "By definition, a UTI means you have an infection in the urinary tract. How can you have a UTI without the 'I'?"
Also, the "prevention" results were pretty sad, according to Vox. Apparently, if you drink cranberry juice every day for over three years, you'll stop one "symptomatic UTI," which is what it's called when you feel like you have one, but haven't had a test.
All in all, the results weren't so great for women who actually have a UTI.