Ask the Vegan Vet: Urinary Stones

"I'm considering switching my dog over to a vegan diet. Do I need to be worried about urinary stones?" - Luke T.

There has never been a published study on the issue of vegan dogs getting urinary stones.  There is only some anecdotal evidence that cats, and possibly dogs, may be more prone to urinary stones on a vegan diet.  Being a vegan vet with an interest in vegan pet diets, I have heard directly about animals with bladder stones.  Plant-based diets are alkalinizing.  For humans, this seems to be very beneficial.  In animals however, a diet that is too alkaline can cause certain types of stone formation (typically struvite).  On the flip side, a diet that is too acidic also predisposes animals to urinary bladder stone formation (typically Calcium oxalate).  

During my 10+ years as a vet, I have seen in my practice at least 50 animals, about equally dogs and cats, with urinary bladder stones.  None of them ate a vegan or vegetarian diet.  (I only heard about vegan animals with stones from others, but have yet to see one in my own practice).  Animals get bladder stones.  It happens.  Certain breeds are also particularly predisposed such as Shih Tzu's, Dalmations, Schnauzers and Bichon Frise's.  Bladder stones are more common in female dogs, perhaps because they're more likely to have UTIs (the reason for this is a wider diameter urethra and thus easier access for ascending bacteria).

Here's what I recommend to prevent bladder stone formation, especially in animals predisposed by breed or prior urinary issues:

1) Increase water intake!  Have fresh, clean water available at all times.  Consider adding water to food.

2) Purchase urine pH strips and test.  Check the urinary pH weekly for the first 3 months, then at least monthly thereafter.  You can purchase urine test strips online. Normal dogs typically have urine pH between 6-7 but can vary.

3) If urine pH is consistently alkaline (2 or 3 consecutive readings over 7), see the vet for a full urinalysis and recommendations or add a bladder health supplement such as Vetriscience UT Strength STAT to acidify the urine.  You can add a glucosamine supplement like this one for bladder wall health.

I hope this answers all your questions and concerns! Thanks, Luke!