Can Cranberry Juice Treat Bladder Infections?

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Does Cranberry Juice Work Against Bladder Infections?

How could any bacteria cause a bladder infection without just getting flushed away—literally? Bladder infections may make sense if we’re not drinking enough or if we leave behind a stagnant pool because we can’t empty completely (as in men with enlarged prostates).  However, in most people there should be a constant flow of water. The way bladder infection-causing E. coli hold on is that they evolved  finger-like projections (fimbrae) they can use to stick to the walls of the bladder so they don’t get washed away.

Almost 30 years ago, it was demonstrated that if you drip cranberry juice on E. coli, their fimbrae aren’t able to stick as well. Grape juice doesn’t work, nor does orange or apple juice. Even white cranberry juice made from unripened berries doesn’t work, suggesting that it’s one of the red phytonutrients that’s the active ingredient. For more on these natural plant compounds, see Phytochemicals: The Nutrition Facts Missing From the Label and for those doubting the power of plants, Power Plants.

Even if it works in a petri dish, though, we don’t pee cranberry juice. How do we know that the anti-adherence phytonutrients are even absorbed through the gut and make it into the bladder? Subsequent studies have shown that if you drip the urine of someone who drank cranberry juice onto E. coli, they don’t stick as well either. Now we’re getting somewhere. If you check out my 4-min video Can Cranberry Juice Treat Bladder Infections?, you can see the stickiness of strains of E. coli wading in urine from someone drinking water, and the stickiness in the urine of someone drinking cranberry juice. Within hours of consumption there’s a drop in E. coli adherence that appears to last throughout much of the day. So might cranberries really help prevent bladder infections?

The best way to prevent infections is to not get infected in the first place, which may involve the avoidance of chicken so you’re not constantly re-infecting yourself (see my last video Avoiding Chicken to Avoid Bladder Infections).

If that doesn’t work, however—if your gut remains stubbornly colonized with these bad bladder bugs—various tested cranberry products appear to reduce the recurrence of bladder infections by about 35 percent. Not as effective as antibiotics, but cranberry juice doesn’t foster antibiotic resistance and has fewer side effects.

There’s no good evidence to suggest cranberries are an effective treatment, though, which makes sense. Cranberries prevent the initial adherence, but that occurs at the start of the infection. When the infection is present and already stuck, there’s no clinical data to suggest that cranberries are effective in the treatment of urinary tract infections, meaning it doesn’t work better than placebo—but placebos work! For example, ibuprofen seems to work just as well as antibiotics for the treatment of uncomplicated urinary tract infections.

Some people really do need antibiotics—pregnant women, children, men, those with kidney infections, and systemic symptoms like nausea and vomiting. For most healthy women, though, bladder infections just go away on their own without antibiotics. Women who drink cranberry juice and have their symptoms disappear may falsely attribute their recovery to the juice. However, when it comes to most UTIs, nothing works–as in nothing, a sugar pill, actually works!

I discuss the controversy around doctors giving placebos in The Lie That Heals: Should Doctors Give Placebos?

What else can cranberries do? Check out my recent videos Which Fruit Fights Cancer Better? and Cranberries Versus Cancer.

How can you consume cranberries palatably? Check out my recipe for Pink Juice with Green Foam.

If cranberries are so good at keeping bacteria from sticking to the wall of the bladder, what about keeping bacteria from sticking to other places like our teeth? I touch on that in my video Childhood Tea Drinking May Increase Fluorosis Risk.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

11 responses to “Does Cranberry Juice Work Against Bladder Infections?

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  1. I don’t know about the cranberry juice being a placebo. I have had many, many, uti’s and suffered greatly at first. Then I was told to drink some cranberry juice. Silly me drank what I could find in the middle of the night which was cranberry juice cocktail (loaded with sugar). Maybe it was the gallon of juice and water that flushed out my urinary tract. Then I switched to 100% cranberry juice (no sugar, just the berries). I would drink about a half a gallon of the juice with water over a 2 hour period. Added to this I would eat asparagus (canned, frozen, whatever I had). Ah, stinky pee and no more urge to go. I never had an infection get to my bladder (lucky or I just learned fast) and I never saw a doctor for it. So, should I ever get an infection again (not in my plan) I will consume the juice and the wonderful asparagus. It works for me, placebo or not.

  2. Parsley tea works. I know you just said that even placebos work, so you may think that’s what going on. But I swear! Water steeped in parsley has cured every UTI I’ve ever had, within a day. And I’ll go further. I’ve never known anyone for whom parsley tea didn’t work on their UTI. And I bet no one will ever know anyone for whom this doesn’t work. How’s that for confidence? :-)

      1. Fresh parsley. Let a big handful of it steep in a cup of hot water, then drink the water. You’ll feel a little better within minutes after the first cup (maybe 15 minutes.) And with each cup, you’ll keep feeling better. For me, a full blown UTI will be gone within 24 hours with the parsley tea — maybe 6 to 8 cups drunk within that 24 hours.

  3. I have been through the UTI wars…and have also been diagnosed with interstitial cystitis….and have had a serious round of kidney infection. I have passed menopause (never having these prior to perimenopause)…and have been WFPB (whole food plant based) for several years. I have tried the cranberry track…. but doesn’t seem to work. I will try the parsley next…as I read in the column. I still have chicken in the house as I make my dog’s food (usually 1x per month and then freeze the rest). This time I put gloves on when I handled/cooked the chicken. I use a crock pot…and only use it for the dog food. But that video was a wake up call!!

    Of recent, I have been researching focusing on pH…and keeping your urine between 7.2 – 7.4. I shifted what I had been eating (WFPB…no processed foods) to include more leafy greens….avocados….of course fruits and vegetables…and my urine has been slightly above this range (7.6-8.2…I take the pH of first morning urine…and if home, throughout the day..this is based on a pH meter that I purchased…ok not as much fun as peeing on the cabbage…but a lot easier…and a bit more precise). The theory being that bacteria can not live in a basic environment. Not only did I get a bladder infection accompanied by fever this time… but was told by my doctor…that there are several bacteria that live in an alkaline environment. {sigh}. So I am on another round of antibiotics.

    My doctor…once I am well…wants to do some radioactive testing (which I am NOT thrilled about…and want no part of) to see if there are some issues with the kidney (kidney stones? are her thought). But being on a WFPB diet I thought my risk of getting kidney stones was low?

    I have a couple of questions….

    1) can your urine be too basic?

    2) What are some possible health risks from too high a pH. (In the video about the cabbage, nothing was mentioned).

    3) can someone eating a WFPB diet get kidney stones?

    4) If so, wouldn’t there other evidence to indicate this is happening (blood work?)

    5) If so, are there foods to avoid on WFPB diet that would help stop the formation of kidney stones?

    6) What else can I do to help stop UTI?

  4. I always get UTI after sex. My doctor suggested taking 1 pill of antibiotics prior to it or do the surgery. Haven’t had chicken or any meat for four years husband though has just stopped eating it. Cranberry juice (or pills) helps but not always. Ordered some D-Mannose…hopefully that helps and I won’t have to take antibiotics anymore. It’s been going on for almost two years now. When I asked my doctor what should I do if I want to get pregnant (Those antibiotics should not be taken then but I’ll get UTI and then what do I do), he said no one has ever asked that question before and that he doesn’t know!( That’s so frustrating…

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