You might've heard cranberries help prevent urinary tract infections (UTIs). But are these berries and their juice really good for your urinary health?
Studies show mixed results. Some suggest cranberry juice or cranberry pills can help prevent UTIs, especially if you're a woman (or assigned female at birth) and have a higher risk for these infections. But other research doesn't show much evidence they help. Most experts agree more studies are needed.
One review of how well cranberries may help prevent UTIs suggested they reduce your risk by 30%. In nonpregnant women, they may lower the chances of repeated UTIs by 26%. Another review of research found people who drank cranberry juice had 54% fewer UTIs than those who got no treatment or drank beverages not containing cranberries. Cranberry juice also led to 49% less antibiotic use compared to a placebo drink. It cut the use of antibiotics even more compared to no treatment at all. But the evidence isn't strong or consistent.
"Taking cranberry compounds -- in any form, liquid or tablet -- reduced the symptoms of UTIs by more than five times," says Christian Moro, a biomedical scientist who reviewed evidence for cranberry for UTIs at Bond University in Queensland, Australia. "[After] accumulating the studies, we had a moderate to low certainty that the data was clear. So, additional high-quality randomized controlled studies are very much welcome."
The American College of Obstetricians and Gynecologists (ACOG) says unsweetened cranberry juice or cranberry pills may lower your risk for a UTI. But it isn't clear how much cranberry juice you need or how long you need to drink it to keep you from getting a UTI. The American Urological Association says doctors can suggest cranberry use as a way that might help prevent repeated UTIs. It's possible that having cranberries could help you avoid antibiotics or use them less.
"In general, I do recommend cranberry supplementation for people, both with recurrent UTIs and those people who are just looking to prevent UTIs," says Anne Cameron, MD, clinical professor of urology at Michigan Medicine in Ann Arbor. Recurrent UTIs are when you have three in a year, or two in six months.
"Even for people who are otherwise healthy, who are asking for advice on avoidance of UTIs, I do recommend cranberry, either supplementation or juice, because it's very nontoxic. There are very few side effects. There are very few downsides."
Cranberries won't work for everyone, and drinking cranberry juice doesn't guarantee you'll be free of UTIs. You might find it hard on your stomach to drink or take enough cranberries. And they don't treat UTIs you already have. See your doctor if you think you have a UTI.
How Do Cranberries Prevent UTIs?
Cranberries and cranberry juice are mostly water. But they have other substances too, including:
- Quinic acid
- Malic acid
- Citric acid
- Glucose
- Fructose
Scientists used to think cranberries protected you against UTIs by making your pee more acidic. That means your pee is less friendly to bacteria like Escherichia coli (E. coli), which are usually to blame for UTIs. But other studies didn't find a lasting difference in acidity.
Now, researchers have found that substances in cranberries make it harder for infection-causing bacteria to stick to the walls lining your bladder. If E. coli can't stick to your bladder, it can't cause an infection in your urinary tract. They traced this effect to two components in cranberries: fructose and proanthocyanidins (PACs). While some other foods also have PACs, those in cranberry juice are unique in stopping adhesion.
"The bacteria, the E coli specifically, stick to this substance, and you pee it out," Cameron says.
What's the Best Cranberry Juice for UTI?
It's hard to say for sure what cranberry juice is best for UTIs or how much you should drink. Some recommendations suggest drinking a little over a cup (about 300 milligrams) each day. Some studies had participants drink 200 to 250 milliliters twice a day. The key is the amount of proanthocyanidins (PACs) in the juice. It's recommended to get 36 milligrams of PAC per day. Juices containing more cranberry and more PAC may deliver greater benefits than cranberry cocktails, which may have apple, grape, or other juices in them.
"You have to check the ingredient list," Cameron says. "It has to say 100% juice and, when you look at the ingredients on the side, the only ingredient should be cranberry juice."
Moro says the amount needed to help with UTIs can vary depending on lots of factors, including whether you're drinking enough fluids otherwise.
"Any cranberry compounds with increased fluids are beneficial," Moro says. "As the definition of 'juice' varies between countries and commercial products, we've simply been clarifying that it's fluids plus cranberry, which seems to have the most favorable outcomes. If you don’t find cranberry drinks palatable, the second best thing is to regularly reach for a large glass of water."
What Are Cranberry Pills for UTIs?
You can buy cranberry supplements in capsules, tablets, or powders. Because the evidence is limited, it's hard to know what cranberry pills or supplements work best for UTIs. It's important to remember supplements aren't regulated the same way as medicines. The way cranberries get processed can change their chemistry.
"If you're just taking the crushed stuff left over from the juice-making process, which is otherwise used as animal feed, you're not really getting the PAC that you need," Cameron says. "The PAC also needs to be soluble. If the PAC is bound up in twigs and skins and seeds, when you swallow it, you just excrete it unabsorbed. The PAC that actually works and is absorbed is the one that comes from the actual juice. So, the companies that take juice and extract the PAC from the juice, which is a much more expensive process, actually get you what you're expecting."
Look for supplements with at least 36 milligrams of PAC. Supplements come with less sugar and calories compared to juice. To get the most benefit, follow your supplements with plenty of water.
"If you're drinking juice, you're drinking more fluid," Cameron says. "So, if you are taking the supplements, make sure that you have them with enough fluid to make sure that you're actually getting the full benefit. A [good quality] supplement plus a couple of glasses of water is probably equal to the juice minus the sugar."
Things to Keep in Mind About Cranberries for UTIs
Drinking cranberry juice is usually safe enough to try. But because of its acidity, it might be hard for you to take. It could upset your stomach or give you diarrhea. It may be more likely to cause trouble if young kids drink lots of cranberry juice. Don't forget that cranberry juice also has sugar and calories.
"The extra calories and sugar each day can add up over time," Cameron says. "For people who are diabetic or trying to watch their calories, that can be a bit of a problem."
Cranberry juice is also high in salts called oxalates, which can make kidney stones more likely. If you have interstitial cystitis, a painful bladder condition, Cameron says the acid in cranberry juice may worsen your symptoms.
If you take the blood-thinning medicationwarfarin, avoid cranberry products or take special precautions, as they can interact with the drug and cause bleeding.
If you like cranberry juice and it doesn't bother your stomach or affect another health condition or meds you take, it may be a good option. If you decide to take supplements, talk to your doctor first. Don't use cranberry juice or other products in place of proven treatments your doctor recommends.
Takeaways
Cranberry supplements or cranberry juice for UTIs may help, especially if you get UTIs often. Some studies suggest they may help lower your risk, but the evidence isn't strong. Don't use them to replace proven treatments for UTIs. While cranberries are generally safe to consume, they could upset your stomach. Talk to your doctor before trying them.
Cranberry Juice for UTI FAQs
How much cranberry juice should you drink with a UTI?
An 8-ounce cup a day may help prevent UTIs or lead to fewer of them. Drinking plenty of water may also help ease UTIs.
What's the fastest way to flush a UTI?
See your doctor right away if you think you have a UTI. You may need medicine. Drinking plenty of water may help flush bacteria out of your bladder or urinary tract faster.
How much cranberry juice should you drink to flush your kidneys?
About 8 ounces a day can help keep bacteria from sticking to your bladder and urinary tract. It's possible cranberries also may have benefits for your kidneys, but more study is needed.