Another one for the “conflicts of interest in nutrition research” files.
Today, Vox’s Julia Belluz takes a fascinating deep dive into how juice companies — in this case, Ocean Spray — game science to perpetuate the myth that cranberry juice prevents UTIs.
- “Conflict of interest in nutrition research is nothing new. Trouble is, consumers are almost always snookered by this shady science. The newest example is a study funded by Ocean Spray, the world’s leading producer of cranberry juices. It concludes that “cranberries can be a nutritional approach to reducing symptomatic [urinary tract infections].”
- “Cranberries contain compounds that are thought to prevent bacteria from sticking to the cells that line the bladder. So cranberry juice makers have long hyped the claim that their products prevent UTIs.”
- “The study had a fantastic veneer of legitimacy: The randomized, double-blind, placebo-controlled trial, published in the American Journal of Clinical Nutrition, involved nearly 400 women at 18 clinical sites throughout the US, as well as a Boston University scientist.”
- “The study wasn’t just funded by Ocean Spray; it was also co-authored by Ocean Spray staff scientists. Not only was the food company involved in nearly every step of the process but its scientists even helped write the manuscript. At first blush, it was hard to see how the company’s involvement might have biased the research.”
- “But there are a few details that raised red flags. According to the study, a glass of cranberry juice a day reduced UTIs by nearly 40 percent in women. Most drugs don’t have such large effect sizes — and analyses of the best available research on cranberries and UTIs, like this Cochrane systematic review, have found that cranberry juice doesn’t reduce the occurrence of UTIs (probably because the juices — or even cranberry supplements — don’t contain enough of the compounds that fight bacteria).”
- “So how did the Ocean Spray group manage to come to such striking conclusions? It turns out this had much to do with how the researchers chose to measure and analyze their data. First, they focused on a much broader — and more favorable — definition of what a UTI is.”
- “I asked independent researchers what they thought of this approach — and they called it “smoke and mirrors.”
- “Even if you ignore these two problems with the research and accept that cranberry juice indeed reduced the risk of UTIs, the result the researchers found was actually pretty dismal in absolute terms: Drinking cranberry juice every day for 3.2 years averted one symptomatic UTI (and remember, that means not necessarily one that’s confirmed through a lab test).”
- “This “landmark study” may not have finally proved that the red stuff is a UTI preventer. But it did remind us of why we need to be skeptical of industry-funded nutrition research.”