Dave Zanoni
Why the details matter before changing your dog’s or cat’s food
When someone tells me their dog or cat has urinary crystals, I understand why the next question is often, “What should I feed?”
Food is something we can control. We want to make a good decision, get our animal comfortable, and keep the problem from coming back.
But my first question is, “Do you know what kind?”
As a nutritionist, I want to understand what the veterinarian found and what the feeding plan is supposed to accomplish. That gives our conversation a starting point. Without those details, choosing a food becomes guesswork, even when everyone means well.
Start with what was actually found
Crystals and stones are different findings. Crystals are microscopic structures that can form in urine. Stones are solid accumulations of material within the urinary tract.
A pet can have crystals without stones, and stones without crystals appearing in a urine sample. Some crystal findings do not require treatment. Others deserve further investigation, especially when they persist or occur alongside symptoms. Even storage and refrigeration can cause crystals to form after a sample has been collected.
That is why “the test showed crystals” does not give us enough information to select a diet. The veterinarian’s interpretation matters more than the word by itself.
From the nutrition side, I want to know whether we are discussing an incidental finding, a diagnosed stone problem, or a plan to help prevent recurrence.
The same feeding approach does not fit every stone
Struvite and calcium oxalate are two common stone types in dogs and cats. Their differences have practical consequences for food selection.
Struvite stones can often be dissolved through a veterinarian-directed plan that includes a specifically formulated diet. In dogs, these stones are commonly associated with certain bacterial urinary tract infections, which also need treatment. In cats, struvite stones usually develop without a bacterial infection.
Calcium oxalate stones cannot be dissolved with food. Nutrition can be part of a plan to reduce the risk of new stones, but it cannot make an existing calcium oxalate stone disappear.
Dissolving a stone and reducing the likelihood of another one forming are different nutritional goals. A food selected for one purpose should not automatically be substituted for a food selected for the other.
There are other stone types, too. These two examples show why I need more than “urinary trouble” before discussing a food change.
Moisture deserves attention
Water is one of the first things I want to discuss when reviewing a urinary feeding plan.
Increasing water intake can help produce more dilute urine, reducing the concentration of substances involved in stone formation. High-moisture feeding is an important part of prevention strategies for several stone types. Depending on the pet and the prescribed plan, that may mean an appropriate wet food or adding water to the existing food.
Fresh drinking water should remain available. If your pet already has a urinary condition, ask the veterinarian how best to increase moisture within that pet’s plan.
Still, moisture is one part of the decision. A wet food is not automatically suitable for every animal with a urinary problem. Its overall formulation and the animal’s other health needs still have to fit.
I would rather help someone make a useful, consistent change than promise that a different food format will solve everything.
Look at the whole diet, not one ingredient
It is understandable to look for one ingredient to remove or one number to lower. Unfortunately, urinary nutrition is more involved than that.
Magnesium, phosphorus, and calcium have necessary functions in the body. Their presence in a food does not make that food harmful. What matters is the amount supplied, the balance of the diet, and whether the formulation is appropriate for the animal’s condition.
For example, diets used to manage sterile struvite may control magnesium and phosphorus while promoting more acidic urine. Calcium oxalate prevention has different priorities, including avoiding inappropriate urine acidification.
That does not support cutting minerals indiscriminately or trying to rebuild a balanced diet with supplements at home.
When evaluating a food for a pet with a diagnosed urinary condition, I want information about its intended use and nutritional formulation. An attractive ingredient list or the words “urinary health” are not enough to establish that it will accomplish the specific goal we need.
Urine pH is not a score to chase
Urine pH describes how acidic or alkaline urine is. It is useful information, but it does not identify a stone on its own. Diet, medications, disease, and sample handling can influence the findings. Even the crystal type seen in urine does not always match the stone type present.
Lower is not automatically better. Struvite is favored by more alkaline conditions, while acidifying the urine can be inappropriate for a pet prone to calcium oxalate.
For that reason, I would not suggest an acidifying supplement simply because someone was told their pet’s pH was high. I would want the veterinary recommendation first, including whether a change is needed and how its effect will be checked.
A number can help guide a feeding plan. It cannot replace one.
The extras belong in the conversation
When I ask what a pet eats, I mean everything: the main food, treats, chews, table food, toppers, and supplements.
That is not criticism. Most extras are given out of affection. But they still belong in a complete diet history.
This is especially important during stone dissolution. The selected diet is being used to produce particular changes in urine. Additional foods can interfere with following that plan as intended. Veterinary dissolution protocols may require exclusive feeding, so treats and toppers need approval rather than assumptions.
Before we add something “for urinary health,” we should be able to answer three questions: What is it supposed to do? Does that match this pet’s needs? Is it compatible with the existing plan?
If those answers are missing, I would hold off.
Make the feeding plan clear
A useful nutrition conversation starts with a few practical questions:
- Were crystals found, stones found, or both?
- What type is suspected or confirmed?
- Is there an infection or another condition affecting food selection?
- Is the goal dissolution, prevention, or something else?
- Which foods, treats, and supplements are allowed?
- When will the veterinarian reassess the results?
Follow-up matters. Looking more comfortable does not, by itself, confirm that stones are gone. A veterinarian may need repeat urine testing or imaging to assess progress.
Not every urinary symptom is caused by stones or infection, either. Cats can have conditions such as feline idiopathic cystitis, where stress and environmental factors may also need attention. Food alone cannot address every cause of urinary discomfort.
My job is to help owners understand the nutritional purpose of the plan and put it into practice. That includes being honest about what food can accomplish, where it has limitations, and when we need more information.
You do not need to understand every term on a laboratory report. You do deserve to understand why you are feeding what you are feeding.
Feed with purpose, not guesswork.
An urgent exception: If your dog or cat repeatedly strains to urinate and passes little or no urine, seek veterinary care immediately. A urinary blockage can be life-threatening. Male cats are especially vulnerable. Do not wait for a food change to help.
Sources
- Minnesota Urolith Center: Being crystal clear about crystalluria.
- Merck Veterinary Manual: Urinalysis.
- Merck Veterinary Manual: Urolithiasis in Dogs.
- Merck Veterinary Manual: Urolithiasis in Cats, updated May 2025.
- Lulich JP et al. ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats. Journal of Veterinary Internal Medicine. 2016;30:1564–1574.
- Taylor S et al. 2025 iCatCare consensus guidelines on the diagnosis and management of lower urinary tract diseases in cats. Journal of Feline Medicine and Surgery. 2025.
- Cornell Feline Health Center: Feline Lower Urinary Tract Disease.
Sources checked September 18, 2026.