Cranberry & Pet Urinary Health — Miracle Berry or Fad?

Author: Dr. Beth Turner

Published: September 28, 2023

Updated: February 8, 2024

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bowl of fresh cranberries that are good for urinary health-canva

Are you wondering if cranberries and cranberry products are good (and potentially beneficial) for pets? Well, you are not alone!

Cranberries are typically a seasonal fruit used around the holidays. I mean, what would a holiday meal be without them? So, if we enjoy those yummy red berries so much, are they safe for our pets to gobble down, too?

And what about all those cranberry-containing products touted and marketed with terms such as “urinary health” or “urinary care."

Can they truly be helpful for pets that suffer with urinary tract issues?

Hopefully, by the time you are done reading this article, all your questions (at least about cranberries) will be answered. And if they aren’t, please feel free to ask us in the comments below!


Are Cranberries Safe and Beneficial for Pets to Eat?

Besides being yummy and very versatile, cranberries are high in nutrients and antioxidants. People have used this superfood as an herbal remedy for just about every ailment. But are they safe and beneficial for pets?

In moderation (1 to 2 tablespoons/day), as with other safe fruits and veggies, cranberries in their "au natural” fresh state or even dried are safe for dogs and cats.

So, what benefits do cranberries offer? Since they are high in antioxidants, they help support your pet’s immune system and decrease inflammation. They are a good source of fiber, vitamins (C, E, B1, B2, and K), copper, manganese, and potassium.

When Good Becomes Bad!

Too much of a good thing, even if safe and beneficial, can turn into a bad thing. Not all versions or presentations of cranberries are healthy or safe for pets.

cranberry sauce that is unsafe for pets
Forms of Cranberries That Are Unsafe for Pets

Generally, when cranberries are dried, cooked, sauced, or even juiced, there can be added ingredients (sugars, xylitol, grapes, raisins, or even alcohol) that are toxic. ALWAYS, ALWAYS, ALWAYS read the ingredient list to check for any toxic items before ever giving any food items containing cranberries to your dog or cat. For example, it isn’t recommended to give cranberry sauce (especially to diabetic pets) or juice since they are much higher in sugar, may cause stomach upset (such as vomiting and diarrhea), and may contain ingredients that are not safe for pets.

Too many cranberries, especially the smaller dried kind, can result in stomach upset and cause weight gain.

Note: Dried cranberries often have added sugars. Additionally, even if they are unsweetened, they are higher in calories, sugar, and carbohydrates as compared to raw berries.

Cranberries can be a potential choke hazard, especially for pets that have problems chewing, such as seniors or those with dental issues. They may also be too big for some toy and small breed dogs and cats to chew and swallow.

How Cranberry (Possibly) Helps With UTIs in People and Pets

For decades, doctors have been telling women with urinary tract infections (UTIs) to drink cranberry juice. Initially, the thinking was that 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 not to 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) who drank cranberry juice cocktail prevented E. coli bacteria from sticking to the lining of cells and then 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.

In 2016, a study was conducted in dogs to determine if cranberry extracts prevented urinary tract infections and adhesion of E. coli to Madin-Darby canine kidney (MDCK) cells. The result of the study was that none of the 12 dogs developed a UTI, and urine cultures also showed a significant reduction in bacterial adhesion. The conclusion was that oral administration of cranberry extract may be a benefit in preventing UTIs from developing and E. coli adherence.

In 2022, a study was released that evaluated whether cranberry extract could reduce lower urinary tract and gastrointestinal signs in cats that have feline idiopathic cystitis (FIC). The group treated with the oral nutritional supplement containing cranberry extract had a disappearance of lower urinary tract signs by day 30 and a significant improvement in gastrointestinal signs and bladder ultrasound; there were no significant differences in the urinalysis of the control versus the treated group. This suggests that a reduction in lower urinary tract and gastrointestinal signs is possible if cats suffering from FIC are supplemented with cranberry.

jack russell and brown and white cat under a blanket

So, that cinches it — cranberries effectively prevent and treat urinary tract infections and certain associated symptoms! Right? Well, yes, no, maybe…I know it is frustrating.

Why the dilemma? These studies did not include large sample groups; some of the results come from in vitro aspects of the studies rather than from actual patients, and in general, the results are not consistent. Therefore, one cannot definitively say cranberry extract is 100% effective (or partially effective).

But what these studies do confirm is that there may possibly be potential benefits to giving cranberry extract, BUT more high-quality studies need to be conducted to prove or disprove its benefits.

I would suggest three main “takeaways” from this:

  1. The proanthocyanidins in cranberries can prevent the adhesion of P-fimbriated E. coli bacteria to tissues within the urinary tract. Its application would be most likely beneficial in the prevention of reinfections of UTIs caused by gram-negative organisms. It likely will not effectively eliminate established resistant infections or relapse cases caused by infected stones.

  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. This is very important considering the rising concern of antimicrobial resistance with the overuse of antibiotics.

    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). 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 pets!

    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 (especially in animals) are lacking. Before starting any cranberry products, consult with your veterinarian to be sure that it is safe to use them based on your pet’s health status and confirm what products are reputable.

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


Cranberry Supplements for Pets

cranberry supplement for dogs and cats-canva

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

Paxon (for dogs) by Vetoquinol is a beef-flavored chewable tablet.

Remember, do not use products meant for humans as they may contain ingredients that are toxic to pets.

 

Possible Risks of Trying Cranberry for Your Pet's UTIs

If you or your veterinarian want to try a cranberry supplement for your pet’s UTIs, there may be some benefits. 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 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 can potentially have a negative impact on cats!

Usage, Time, or the Wrong Condition

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.

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 few days, 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.

Most people who bring their cat or dog into the vet hospital with concerns about 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 frequently isn’t.

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 Pet'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. 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. Beth Turner

Dr. Beth Turner

Beth Turner is a veterinarian with over 20 years of experience. She graduated from North Carolina State College of Veterinary Medicine and following graduation, she began her career as an associate veterinarian and worked closely with the local shelter.

In 2007 she accomplished her dream of practice ownership, designing and building her own clinic. Another meaningful role, while running her clinic, was serving as her county's shelter veterinarian. This gave her the opportunity to help improve the lives of many animals in her community as well as work with the rescue she loved. She sold her practice in 2019 to move across the country.