Cranberry & Pet Urinary Health — Miracle Berry or Fad?

Author: Dr. Jason Nicholas

Published: November 20, 2016

Updated: August 1, 2022

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cranberries and pet urinary healthCranberry products — are they good for pets?

Go to many of the popular pet blogs or pet supply stores these days and you’re likely to see cranberry-containing products touted and marketed with terms such as “urinary health” or “urinary care."

But what’s the real deal with cranberry — is it really a “cure-all” for your cat or dog’s urinary issues? Or does cranberry just have a good publicity agent?

Let’s cut through the clutter (and fancy marketing terms) and explore the truth about the benefits of cranberry to urinary tract health for cats and dogs. If you really want to try using cranberry supplements for your pet, scroll further down for some product options to consider.

How cranberry (possibly) helps with UTIs

For decades, doctors have been telling women with urinary tract infections (UTIs) to drink cranberry juice. Initially, the thinking was that the cranberry juice would make the urine more acidic (lower pH) and thus less hospitable for the bacteria, thereby preventing and treating infections. This turned out to not be the case though, as cranberry juice only lowers the urinary pH slightly, to a clinically insignificant degree.

A 1984 study then uncovered what may be the reason why cranberry may help with UTIs. This study found that the urine of people (and then mice) that drank cranberry juice cocktail was able to prevent E. coli bacteria from sticking to the lining of (adhering to) cells, and therefore colonizing and establishing an infection.

Then a 2007 study showed that it’s the proanthocyanidins (PACs), a group of compounds found in cranberries (and other berries, including blueberries), that is responsible for the “anti-adhesion” properties of cranberries and that they can specifically prevent adhesion of certain types of E. coli bacteria to the urothelium, the lining of the kidneys, bladder, and other tissues that make up the urinary system.

So, that cinches it—cranberries are effective at preventing and treating urinary tract infections! Right? Well, not so fast there crusher. Turns out it’s not a “slam dunk,” it’s not so cut and dry. Not according to the well-respected and unbiased Cochrane organization.

Cochrane is a “global independent network of researchers, professionals, patients, carers, and people interested in health.” They routinely conduct thorough reviews of the scientific literature to help ensure that healthcare decisions based on the scientific literature are the best they can be.

In 2012 Cochrane updated their review of the scientific evidence behind the benefits of cranberry to UTIs, they scrutinized a total of 24 studies that had been conducted on the subject. Their conclusions are as follows…

  • Cranberry juice appears to be less effective at decreasing the number of symptomatic UTIs than originally thought.

  • Cranberry products were not proven to be statistically superior to antibiotics in the treatment of UTIs.

  • Given the large number of dropouts/withdrawals from studies (mainly attributed to the acceptability of consuming cranberry products particularly juice, over long periods), and the evidence that the benefit for preventing UTI is small, cranberry juice cannot currently be recommended for the prevention of UTIs.

    Other preparations (such as powders) need to be quantified using standardized methods to ensure the potency, and contain enough of the active ingredient, before being evaluated in clinical studies or recommended for use.”

    Spoon of cranberries for pet health

So, does cranberry help prevent and/or treat UTIs in people or pets?

The short answer is possibly … but we don’t know for sure to what degree. Frustrating, I know. But I would suggest three main “takeaways” from this …

  1. The proanthocyanidins in cranberries can prevent adhesion of specific strains of E. coli bacteria to tissues within the urinary tract.

  2. Though cranberry products were not proven to be statistically superior to antibiotics for treating UTIs, they also were not proven to be statistically inferior to antibiotics for treating UTIs. Meaning that “cranberry products” may be at least as effective as antibiotics at treating UTIs.

    That said, it’s very important to keep in mind that this effect has only been studied and demonstrated in urinary tract infections with certain strains of a particular type of bacteria, Escherichia coli (E. coli). And although E. coli is the most common type of bacteria that causes UTIs in cats and dogs, it certainly is not the only type of bacteria that causes UTIs in cats and dogs!

    That’s why bacterial cultures are so important when dealing with UTIs in pets, especially when the pet is suffering from frequent or chronic UTIs. That’s why we vets so often recommend and require urine testing for cats and dogs with “urinary issues.”

  3. Not all “cranberry products” are the same, and there’s no standardized dose established as yet and actual scientific, clinical studies are lacking.

Questions? If you'd like to speak with a veterinarian about using cranberry products with your pet, Click here

Cranberry Supplements for Pets

With all that I've stated in this article if you'd like to try a cranberry supplement for your pet suffering with urinary issues, though actual scientific evidence to back up their use is lacking, many people report good results with the three brands highlighted below:

Crananidin Pet Supplement (for dogs): Produced by Nutramax Laboratories, this product is a chewable tablet.

Cranberry Comfort (for both cats and dogs): Produced by Vet Classics, this product is a soft chew.

Cranberry Bladder Bites (for dogs): These chewables come in two flavors, bacon and chicken.

Pill supplements cranberry

Possible risks of trying cranberry for your pet's UTIs

If you or your vet wants to try a cranberry supplement for your pet’s UTIs there may be some benefit. And while it’s not likely to hurt, there could be some risks associated with doing so. This is mostly because many “urinary tract health” supplements for pets don’t just contain cranberry, many often contain other compounds too. Some of these “other ingredients” can pose risks to cats and dogs; here are three of them:

  • Oxalates — Since cranberries contain compounds called oxalates, there is a potential risk that giving cranberry supplements to cats or dogs, especially one that has already had oxalate crystals/stones or has a predisposition to forming oxalate crystals/stones, can increase their risk of developing oxalate urinary crystals and/or stones either within their bladder (called “cystoliths”) or their kidneys (called “nephroliths”). This urinary oxalate-increasing effect of cranberry supplements has been studied and proven in people.

  • Vitamin C — Many of the urinary tract health supplements also contain vitamin C, which is added to make the urine more acidic. While this can make the urinary environment less favorable for bacteria to thrive and infect, this can also increase the risk for calcium oxalate crystal and stone formation. Furthermore, when vitamin C (ascorbic acid) is broken down within the body oxalates are produced, which further increases the risk of oxalate crystal and stone formation within the urinary tract. This study showed the increased levels of oxalates in urine and the increased risk of oxalate kidney stones in response to high-level vitamin C supplementation in people.

  • Xylitol — While I’m not currently aware of any cranberry urinary health products that also contain xylitol, it’s certainly possible that they’re out there or may creep up. After all, xylitol is everywhere and in everything these days—check out our list of over 700 products with xylitol in them! And some people even tout xylitol as an effective treatment for UTIs. While it’s safe for people, xylitol is extremely poisonous for dogs!

And it’s not just the additional ingredients in cranberry supplements that can cause problems for cats and dogs, it’s also the risk of “trying” them too long and in the wrong situations and not getting your pet the care and treatment they might actually need.

So if your pet is also vomiting, has a decreased appetite, has decreased energy, or other concerning signs along with their “urinary issues” please skip the cranberry supplements and get them to the vet. Similarly, if their “urinary issues” don’t clear up within a week, or if they’re getting progressively worse while on a “urinary health” supplement, please just get them to the vet. It could be something other than a UTI, and it could be something far worse.

Cat lying on bed

Most people who bring their cat or dog into the vet hospital with concerns of peeing outside of the litter box, leaking urine in their bed, asking to go out more frequently, blood in the urine, or other similarly concerning signs often believe that their pet has a urinary tract infection (UTI). And while that is sometimes the case, it isn’t always, and in fact, frequently isn’t. For example:

Cat peeing outside of the litter box?

It could be a UTI, but it could also very likely be …

Dog leaking urine in their bed?

It could be a UTI, but it could also be …dog lying in dog bed

  • Bladder stones
  • Bladder tumor
  • Brain tumor
  • Loss of urinary sphincter control
  • Canine cognitive dysfunction (“Doggie Dementia”)
  • Kidney failure
  • Diabetes
  • Cushing’s disease
  • Liver failure
  • Nervous system dysfunction
  • A congenital anatomical problem (e.g., a patent urachus or ectopic ureter)

Dog asking to go out more often?

It could be a UTI, but it could also be …

Noticing blood in your dog or cat's urine?

It could be a UTI, but it could also be …
  • Bladder tumor
  • High blood pressure (hypertension)
  • Bladder or kidney stones
  • Non-infectious bladder inflammation (sterile cystitis)
  • A “coagulopathy” (problem with the blood clotting system)
  • Trauma
  • A foxtail/grass seed awn, or another “foreign body”

Should you use a cranberry supplement for your cat or dog's urinary tract health?

Unfortunately, it’s not a straightforward answer. As you can see, it depends on the specific “urinary issue” your pet is having, the cause(s) of that issue, their baseline risk for developing urinary crystals and stones, and the concentration of proanthocyanidins and the “other ingredients” in the supplement you are planning to use. I’m sorry I can’t give you a simple answer, but as you can see, it’s not a simple question.

At least now you have all the information and factors you need to consider when deciding on whether or not a cranberry supplement is appropriate for your pets.

Do you use a cranberry supplement for your pet’s urinary tract health? What type do you use? What are your feelings on whether or not it’s working to help your pet? Have you experienced any problems using a cranberry supplement with your pets? We’d love to hear about your experiences in the comments section below.

About the author

Profile picture for Dr. Jason Nicholas

Dr. Jason Nicholas

Dr. Nicholas graduated with honors from The Royal Veterinary College in London, England and completed his Internship at the Animal Medical Center in New York City. He currently lives in the Pacific Northwest.

Dr. Nicholas spent many years as an emergency and general practice veterinarian obsessed with keeping pets safe and healthy. He is the author of Preventive Vet’s 101 Essential Tips book series.

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