Updated: Sep 1
Urate urolithiasis, while not the most common urolith (or urinary tract stone) identified in dogs and cats, is quite prevalent in certain breeds of dogs (Dalmatians, Bulldogs, and Black Russian Terriers). Urate stones form because of hyperuricosuria (increased uric acid levels in the urine), which is either due to a genetic mutation, underlying liver disease or may be idiopathic (of an unknown cause).
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In our video (see the link below), we talk about what urate stones are, potential underlying causes, and a brief overview of how to manage urate urolithiasis in dogs. In this blog post, we’ll cover the nutritional management of urate stones – including commercial options and some home-cooked alternatives.
So, what does dietary management of urate urolithiasis entail in dogs:
Broadly speaking, there are three main goals to consider when it comes to modifying the diet of a dog with urate stones, namely:
Moderate- to low-protein
As mentioned in our video, purine restriction is important in dogs with urate urolithiasis, in order to limit the amount of purines available for breakdown into uric acid and thus reduce hyperuricosuria (increased levels of uric acid in the urine). Because purines are often high in high-protein diets, purine restriction sometimes requires a degree of protein restriction, or at least minimizing high-purine content foods such as red meats, organ meats or offal, and fish. Food ingredients that are low in purines include dairy products, eggs, most vegetables, and fruits. Thus, these are the ingredients we often reach for when formulating recipes for dogs with urate stones.
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Feeding high-moisture foods (basically, foods with more than 75% moisture content) is equally important, with the goal being to achieve more dilute urine (in dogs, this equates to a urine specific gravity (or USG) of less than 1.020). Anything else that you can do to encourage more water intake would also be super helpful, particularly if feeding a dry diet – so don’t be afraid to try adding some water to each meal. You can also try feeding some high moisture treats, like melon or cucumber, or offering broth frozen into a Kong (in summer!)
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Promoting alkaline urine (in other words, a higher urine pH) is also crucial, as urate becomes more soluble as the urine pH increases. What this means is that patients are less likely to have urate precipitate out of urine and form stones if their urine pH is higher or alkaline.
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Unfortunately, a high recurrence rate is typically seen with urate urolithiasis, particularly in dogs where the underlying cause is a genetic mutation (e.g., Dalmatians and Bulldogs). In these cases, additional medication in the form of allopurinol is generally required. While the use of this drug can be useful in such cases, it is important to note that there is a risk for the development of another type of stone, xanthine uroliths.
Commercially, the most utilized diet for managing such cases is Hill’s Prescription Diet u/d. Other alternatives include Royal Canin Urinary UC Low Purine and Royal Canin Vegetarian dry dog food. For patients with underlying liver disease, it might be worth considering diets like Hill’s Prescription Diet l/d (L/D) or Royal Canin Hepatic.
We recently had a 7-year-old male neutered Dalmatian referred to us for a nutrition consult because of his recurrent urate urolithiasis. We formulated a recipe for this patient using cottage cheese, sweet potato, and pumpkin, along with some green vegetables and fruit. The cottage cheese was chosen because it is low in purines. Ingredients such as pumpkin and certain fruits can be particularly helpful when it comes to increasing the moisture content of the diet – which is why they were included in this diet to achieve a moisture content of around 80%.
We also gave this guys’ pet parents some options for home-made low purine treats, which you can also access using the link below:
It is worth mentioning that diets containing vegetarian proteins can be low in taurine. They can also be low in the essential amino acids methionine and cysteine, from which taurine is produced. There is an association between taurine deficiency and dilated cardiomyopathy in dogs; even though this is likely to be multifactorial, it is a good idea to supplement such diets with taurine as per NRC recommendations.
If you’re interested in having some recipes for a home-cooked diet for your dog with urate stones, please get in touch – we’d be happy to help!