Your Diet May Be Causing Your Urinary Tract Infections

3 minute read

Tough-to-treat urinary tract infections (UTI) that are resistant to antibiotics are on the rise. Now, in a new study looking at human urine published in the Journal of Biological Chemistry, researchers say they’ve discovered why some people are more prone than others to the infections. Intriguingly, diet may have something to do with it.

Early on in an infection, cells produce a protein called siderocalin that blocks bacterial growth, including the growth of E. coli that often causes UTIs, says Jeffrey P. Henderson, MD, PhD, assistant professor of medicine at Washington University School of Medicine in St. Louis and senior author of the study. (It does this by keeping iron away from the bacteria, which need it to thrive.) The researchers wanted to see how the protein worked differently in various samples of urine at restricting the growth of E. coli, so they analyzed the urine from about 50 men and women.

“We found, kind of to our surprise, that there was a really wide range between individuals and how well this protein worked, just depending on that individual’s urinary composition,” says Henderson.

Two common factors emerged in urine that had a better ability to resist bacterial growth: it had a high pH—one that’s more alkaline, in other words—and higher levels of certain metabolites formed by gut microbes. That metabolite isn’t made from human cells, Henderson says; rather, they come from the diet or are metabolized by bacterial cells from dietary sources. “It looks like this protein that’s part of your immune system is able to use metabolites in the diet as grips to hold onto iron and keep it away from pathogenic bacteria,” Henderson says. In some people, that system is set up really well, he says, but in those who get recurrent UTIs, it doesn’t seem to work as well.

Both urine pH and metabolite production may be able to be changed through diet, and doing so could potentially offer a treatment strategy in the future, he says. “It may be that we have to adjust multiple things at the same time to get the system to work well, but the appealing part is this is not an antibiotic strategy,” he says. It may allow you to keep your normal flora while keeping bacteria out of the urinary tract.”

Physicians already know how to raise urinary pH with things like calcium supplements, and alkalizing agents are already used in the U.K. as over-the-counter UTI treatments, Henderson says. Knowing how to encourage the metabolites is trickier. The molecules come from phenolic, or aromatic, compounds, Henderson says, and robust food sources include those that we more often hear are rich in antioxidants: coffee, tea, colorful berries, red wine and dark chocolate.

And yes: cranberries, too, are known to make urinary aromatics, which may be why cranberry products are so often used as UTI remedies, Henderson says. “One thing this suggests is that maybe the reason it’s not more effective is that people need both cranberries and a higher urine pH, or they need cranberries and appropriate inhabitants of their intestine, or the right microbiome composition in their gut, for the cranberry part to work properly.”

A treatment without antibiotics would be a boon, but it’s likely a several-pronged approach and for now, more research is needed. “We still have a few more details to iron out before we know exactly how to do that.”

QUIZ: Should You Eat This or That?

Which is better for you: A 1/2 cup of ice cream or 3 scoops of sorbet?
Which is better for you: Half cup of ice cream or 3 scoops of sorbet?Getty Images (4)
Answer: A 1/2 cup of ice cream
Answer: A half cup of ice cream If you eat what you’re craving, you’re more likely to feel satisfied and eat less. And scoop for scoop sorbet contains twice the sugar with none of the filling dairy protein and fat.Getty Images (5); Gif by Mia Tramz for TIME
Which is better for you: Real butter or spray on fake butter?
Which is better for you: Real butter or spray on fake butter?Getty Images; Tara Johnson for TIME
Answer: Butter
Answer: Butter Serving size for spray butters (even low-calorie ones) are around a 1/3 second spray. What on earth does that mean? You're better off using a small amount of real butter as opposed to guessing how much you're using of the mystery melange of up to 20 ingredients.Getty Images (1); Gif by Mia Tramz for TIME
Which is better for you: A sirloin burger or a turkey burger?
Which is better for you: A turkey burger or a sirloin burger?Getty Images (2)
Answer: Sirloin burger Restaurant turkey burgers are often made with dark meat and the skin, so they’re not necessarily better for you (and for the record, they aren't low-fat). You can get a sirloin burger that’s 95% lean meat and gives you 20 g of protein. Just be careful with the toppings.Getty Images (1); Gif by Mia Tramz for TIME
Which is better for you: Almonds or pretzels?
Which is better for you: Almonds or pretzels?Getty Images (2)
Answer: Almonds
Answer: Almonds Almonds are high in protein, fiber and fat and will keep you feeling fuller longer. Give high-sodium pretzels about an hour and you'll feel hungry again thanks to the high-carb no-fat or protein content.Getty Images (1); Gif by Mia Tramz for TIME
Which is better for you: Eggs or Special K?
Which is better for you: Special K or eggs?AP; Getty Images
Answer: Eggs
Answer: Eggs In the morning, you want a meal that will fill you up. Eggs offer protein and fat for satiety, but Special K cereal really only offers carbs and, well, air. If you want carbs to kick off the day, you're better off pairing eggs with a slice of 100% whole grain toast. Getty Images (1); Gif by Mia Tramz for TIME
84505234
Which is better for you: Fat free salad dressing or regular salad dressing?Tara Johnson for TIME
Answer: Regular salad dressing
Answer: Regular salad dressingTo absorb fat soluble vitamins like Vitamins E and K in vegetables you need to consume them with a fat to aid nutrient absorption. Fat-free dressing, meanwhile, is low-calorie but gets its flavor from added sugar and salt.Tara Johnson for TIME (5); Gif by Mia Tramz for TIME
Which is better for you: A low fat cookie or dark chocolate?
Which is better for you: A low fat cookie or dark chocolate?Getty Images (2)
Answer: Dark chocolate “People tend to believe fat free is calorie free,” says Keri Gans, a registered dietitian in New York City. “Go for the real thing.” Fat free cookies may be lower in fat, but higher in other ingredients like sugar. Try a nice piece of dark chocolate for those antioxidants.
Answer: Dark chocolate “People believe fat free is calorie free,” says Keri Gans, a registered dietitian in New York City. “Go for the real thing.” Fat free cookies tend to be high in carbs, sugar and fake sugar. Try a nice piece of antioxidant-rich dark chocolate instead.Getty Images (2); Gif by Mia Tramz for TIME
Which is better for you: Low fat Greek yogurt or 100 calorie Yoplait yogurt?
Which is better for you: Low fat Greek yogurt or 100 calorie Yoplait yogurt?Tara Johnson for TIME
Answer: Low fat Greek Yogurt
Answer: 2% Greek YogurtA little fat is good in the morning to keep you full—plus it has upwards of 17g of protein per container. Fat-free "fruit" yogurt is high in sugar—7 to 10 g per serving—and lower in protein.Tara Johnson for TIME (2); Gif by Mia Tramz for TIME

More Must-Reads from TIME

Write to Mandy Oaklander at mandy.oaklander@time.com