Hannah Zulueta Struvite Stones and Dietetic Vector
If food can be made in a factory, it can be made in the kitchen.
Case Study: Adult mixed breed dog’s urine pH was 7.5 the week his vet found the stones. Four weeks later it is 6.5, and his urine culture is negative. His follow-up x-ray is still ahead of him, so this is a progress report.
A home-formulated diet has a vector
A vector is a direction and a speed. Watch a dog on a long line when he catches a scent. The line tells you where he is going. The tension tells you how fast. A struvite plan has the same two parts. The direction is the same for every dog: infection gone, urine acidic, the stone’s building blocks kept low in the urine, and the stones themselves watched on x-ray. The speed belongs to the dog in front of you. You read it off a test strip each morning and an x-ray at four weeks.
What do I do if my dog was just diagnosed?
Five steps. The rest of the page explains why these are the five.
Call your vet the same day if you see any of this
- Straining to urinate, with little or no urine coming out
- Crying or yelping while trying to urinate
- A hard, painful, or swollen belly
- Repeated vomiting
- Blood in the urine
- Sudden loss of appetite or energy
- No urination at all for several hours
A blocked urethra is an emergency, especially in male dogs, and it can be fatal within a day or two if it goes untreated. Any one of these signs is a reason to go to your vet or the nearest emergency clinic the same day. Do not wait for a scheduled recheck.
What is a struvite stone?
Struvite is mineral scale. If you have ever scraped the white crust off the inside of a kettle, you have held the same idea in your hand: minerals that were dissolved in water came out of the water and hardened. In a dog’s bladder the minerals are magnesium, ammonium and phosphate. Struvite is the crystal the three of them form together.
Whether it forms or dissolves depends on urine pH, the number that says how acidic or alkaline the urine is.
Struvite forms in alkaline urine and dissolves in acidic urine. Every step in this plan pushes that number down.
Why does a bladder infection cause them?
Certain bacteria make an enzyme called urease. In dogs that is Staphylococcus most often, with Proteus the other common one. Urease splits urea, the nitrogen waste the body makes from protein, into ammonia. Ammonia is the sharp smell of a dog bed that got peed on and sat in the sun. In the bladder it does two things at once. It pushes urine pH up toward 8, and it supplies the ammonium the stone is built from.
That is why treating the infection is a central part of dissolving the stone. As long as urease-producing bacteria live in the bladder, they keep manufacturing the exact conditions the stone needs. A diet can push back, but it is pushing uphill.
What did his vet say about the homemade diet?
His vet reviewed the recipe and made three points. All three were fair.
- The recipe did not show what urine pH it would produce.
- It did not show that magnesium and phosphorus were restricted.
- She had never seen a homemade diet dissolve stones. Commercial urinary diets will, if the stones are struvite.
She offered three paths: a commercial urinary diet with monthly x-rays, surgery, or the homemade diet with monthly x-rays to see whether the stones were dissolving. His owner chose the third.
Her third point deserves a straight answer. No published trial has tested a home-cooked diet for struvite dissolution in dogs, so the literature is silent on the question.
Not published means just that. Not published, not disproven. Food trials cost money, and no one has funded one that tests an individually formulated home recipe against struvite dissolution in dogs. A trial like that would likely only happen if a group of dog owners pooled their own money to run it. The home-cooked studies that do exist mostly go one of two ways. University reviews of recipes pulled from books and websites have found many of them nutritionally incomplete, which is a fair warning about formulation, not a test of dissolution. Separately, companies selling their own fresh, complete-and-balanced commercial food have funded published research on their products. JustFoodForDogs is the clearest example, with a 2021 University of Illinois study showing their recipes were more digestible than kibble. That is real, peer-reviewed work, and it sits in the same category as the Hill’s and Purina trials below: industry-funded research on a company’s own manufactured product, not a test of a recipe formulated at home for one dog.
The only way to answer the question for this dog is to measure the same things the trials measured: urine pH, urine culture, and stone size on x-ray at four weeks.
Where do prescription diets fit?
I cook my own food instead of eating food made in a factory. That is a personal choice, and I am not telling you what to do with your dog. Prescription urinary diets, fed alongside antibiotics to dogs whose stones are truly struvite, dissolve those stones. I looked at the trials to see what the data shows.
I looked at these trials to study the structure of the recipes: how low the magnesium went, how much sodium went in, where the urine pH landed, and when the x-ray was taken. Hill’s Pet Nutrition and Nestlé Purina put their scientists’ names on those papers, and I am grateful for it. I looked at their trials because I believe that if a diet that dissolves stones can be made in a factory, it can be made in a kitchen too, as long as I follow the structure they proved out. The recipe in this dog’s bowl is guided by their work.
Food is food, and it can be cooked in a kitchen just as well as it can be made in a factory.
What happened in the first month?
The first-month recipe
That recipe leaned on vegetables that TCM Dietetics has used for a long time to move water through the bladder. Restricting magnesium was not one of its goals. Its magnesium sits at 0.19% of dry matter. The recipe he is moving to now sits at 0.07%.
Dry matter is what is left after the water is cooked off. It is how you compare a wet homemade meal to a dry kibble without the water skewing the numbers.
So the drop in pH over the first month belongs mostly to the antibiotics clearing the urease bacteria. The diet helped by replacing a bone-heavy raw diet, which was delivering more magnesium and phosphorus than he needed, and by keeping him drinking. I am not going to say the stones are dissolving because the pH came down. The x-ray decides that.
What did the dissolution trials actually do?
I read five dissolution trials in dogs and one older experimental study, the methods and results sections rather than the abstracts.
| Study | What they fed | Fully dissolved | Time to dissolve |
|---|---|---|---|
| Wingert 2021 Univ. of Minnesota, 50 dogs | Hill’s s/d, canned, plus antibiotics in 82% of dogs | 29 of 50 (58%) | Median 35 days, range 13 to 167 |
| Toillion 2026 Hill’s and Univ. of Minnesota, 13 dogs | Hill’s c/d Multicare, dry, canned or both, plus antibiotics in 12 of 13 | Nine of 13 (69%) | Mean 71 days, range 15 to 175 |
| Dear 2019 UC Davis, 10 dogs | A dry therapeutic urinary diet, brand masked from owners, plus antibiotics in all 10 | Five of 10 (50%) | Median 31 days, range 19 to 103 |
| Harris 2023 Georgia and Tennessee, 11 dogs | No diet change. d,l-methionine plus amoxicillin-clavulanate | Eight of 11 (73%) | Median two months, range one to four |
| Calabrò 2011 Univ. of Naples, 12 dogs | Two commercial dry dissolution diets, one week of antibiotics | Endpoint was urine pH, reached in both groups | Two months to target pH, three months on diet |
| Abdullahi 1984 Univ. of Minnesota, 12 Beagles | Reduced protein, phosphorus and magnesium, added salt, no antibiotics | Infected five of six; sterile six of six | Infected mean 14.4 weeks; sterile mean 3.3 weeks |
Pick a study to see beyond the abstract.
- Design
- Retrospective review of hospital records, 2007 to 2019, University of Minnesota Veterinary Medical Center.
- Dogs
- 50 client-owned dogs: 36 spayed females, 11 neutered males, three intact males. Median weight 9.2 kg.
- Fed
- Hill’s Prescription Diet s/d Canine, canned.
- Antibiotics
- 41 of 50 dogs, median 30 days.
- Result
- 29 of 50 fully dissolved (58%). Median 35 days, range 13 to 167. First shrinkage seen at a median of 29 days.
Median urine pH went from 7.5 before treatment to 6.5 during it. Urine specific gravity, the measure of how concentrated urine is, fell from 1.035 to 1.015 on the salted canned diet. The odds of complete dissolution were 16 times higher in dogs given antibiotics. Of the 16 failed dogs whose stones were analyzed, 11 contained more than 10% non-struvite mineral. Nine of 50 dogs had a complication: four urethral blockages, three of which were present before the trial began, and two cases of pancreatitis. The authors recommend a recheck x-ray at about one month.
Disclosure in the paper: the Minnesota Urolith Center receives an educational gift from Hill’s Pet Nutrition. Read the paper
- Design
- Retrospective review of records, January 2020 to July 2024, University of Minnesota Veterinary Medical Center.
- Dogs
- 13: 12 spayed females and one neutered male. Median weight 11.3 kg.
- Fed
- Hill’s Prescription Diet c/d Multicare. Eight dogs ate the dry food, one the canned, four a mix.
- Antibiotics
- 12 of 13 dogs, mean 63 days.
- Result
- Nine of 13 fully dissolved (69%). Mean 71 days, range 15 to 175.
The paper states that Hill’s discontinued s/d for dogs and that c/d Multicare is now the food their hospital uses. Median urine pH went from 7.3 to 6.5. Urine specific gravity did not change, 1.031 to 1.028, because most dogs ate the dry food. Every one of the four failures had a calcium-based outer shell on the stone. No dog blocked during the trial. Two dogs got occasional human food or bones and still dissolved.
Disclosure in the paper: the two lead authors are Hill’s Pet Nutrition employees. Read the paper
- Design
- Prospective, single arm, UC Davis.
- Dogs
- 10: nine spayed females and one neutered male. Median weight 18.8 kg.
- Fed
- A dry therapeutic urinary diet, dispensed in an unmarked bag so owners did not know the brand.
- Antibiotics
- All 10, continued until one week after dissolution or surgery.
- Rechecks
- 2, 4, 8, 12, 14, 16, 20, 24 and 28 weeks.
- Result
- Five of 10 dissolved (50%). Median 31 days, range 19 to 103.
All 10 dogs had a Staphylococcus infection confirmed by culture before enrollment. Baseline urine pH was a median of 7.9. Dogs whose stones dissolved finished at a median of 6.73, and only four of the 10 ever reached the study’s target of 6.4. Urine in the responders got more concentrated during the trial, 1.028 to 1.034, and the stones dissolved anyway. The two largest single stones, 3.8 cm and 4.5 cm, both failed.
Disclosure in the paper: a Nestlé Purina scientist is a co-author. Read the paper
- Design
- Prospective pilot, University of Georgia and University of Tennessee.
- Dogs
- 14 enrolled, 11 completed.
- Fed
- Whatever each dog was already eating.
- Treatment
- d,l-methionine near 75 mg per kg twice a day to start, settling near 100 mg per kg. Amoxicillin-clavulanate at 22 mg per kg twice a day.
- Rechecks
- Every four weeks: x-rays, blood gas, bloodwork and urine culture.
- Result
- Eight of 11 dissolved (73%). Median two months, range one to four.
The three dogs that failed had calcium oxalate in their stones and went to surgery. No adverse events were recorded. It shows that an acidifier and an antibiotic alone can reach the same target the diets reach.
- Design
- Randomized, two groups, University of Naples Federico II.
- Dogs
- 12 client-owned dogs with struvite stones.
- Fed
- Two commercial dry dissolution diets. The makers are not named in the paper.
- Antibiotics
- One week.
- Length
- Three months, with urine tested six times.
The two diets had a dietary cation-anion balance of -203 and -192. That number is the balance between the diet’s positively and negatively charged minerals, and a more negative balance tends to acidify urine. Starting urine pH was near 8.0, and bacteria were present in about 70% of samples. Both groups reached the pH range for dissolution by two months, and the diet with the lower balance got there faster. The authors advise stopping a dissolution diet once the stones are gone, to avoid problems from long-term feeding.
- Design
- Experimental, University of Minnesota.
- Dogs
- Female Beagles with induced struvite stones: six with a urease-producing infection, six sterile.
- Fed
- A diet reduced in protein, phosphorus and magnesium, with added salt.
- Antibiotics
- None.
- Result
- Infected dogs, five of six, in two to five months, mean 14.4 weeks. Sterile dogs, six of six, in two to four weeks, mean 3.3 weeks.
Dogs on the diet had lower blood urea and lower blood albumin, higher liver enzyme activity, and liver cell changes that the authors tied to the protein restriction. That finding is why the recipe further down keeps protein moderate.
PubMed ID 6476563. No DOI is registered for this paper.
What does all of that mean for a homemade diet?
- The target is measurable: urine pH below 6.5, a negative culture, and shrinkage on x-ray by four weeks.
- In every trial that used antibiotics, the dogs on them were the ones that dissolved.
- Dissolution happened in dogs whose urine was not dilute. Keeping urine dilute is still part of the standard protocol, and adding water to the bowl costs nothing.
- Starting pH did not predict which dogs would succeed.
- In every study, most of the dogs that failed had stones with a calcium or urate component that diet cannot dissolve.
- The commercial diets earned their dissolution claim through these trials. A homemade diet has to earn it one dog at a time, with the same measurements.
What changes in the recipe now?
The infection is gone, so the recipe changes jobs. It stops being a kidney-friendly transition off raw and starts doing the mineral work the trials describe.
| Nutrient | AAFCO adult minimum | Month one recipe | Struvite recipe | Hill’s c/d Multicare* |
|---|---|---|---|---|
| Magnesium, % dry matter | 0.06 | 0.19 | 0.07 | 0.10 |
| Phosphorus, % dry matter | 0.4 | 0.66 | 0.46 | 0.53 |
| Calcium, % dry matter | 0.5 | 0.75 | 0.58 | 0.68 |
| Sodium, % dry matter | 0.08 | 0.29 | 0.29 | 0.24 |
| Protein, % dry matter | 18 | 48.3 | 42.0 | 22.2 |
*Hill’s does not publish a US dry-matter sheet for this formula. These four numbers are converted from a UK guaranteed analysis (protein 20.0%, magnesium 0.09%, phosphorus 0.48%, calcium 0.61%, sodium 0.22%, all as fed) at an assumed 10% moisture. Treat this column as a reference point, not a lab value.
Magnesium sits just above the AAFCO adult minimum, close to where Hill’s own dissolution formula sits. Phosphorus and sodium follow the same pattern. Sodium is more than three times the AAFCO minimum, to support water intake and urine volume.
The AAFCO number is the floor for a healthy adult dog. It is a different thing from a dissolution target. The Hill’s column is the closest published reference to that target, and the recipe sits near it.
The struvite recipe
Protein is moderate rather than slashed, on purpose. The older dissolution diets restricted protein hard to lower the urea in the urine, along with phosphorus and magnesium, and the 1984 Beagle study found lower blood albumin, higher liver enzyme activity and liver cell changes on that approach. His culture is negative. With the cultured infection cleared, the main source of urease is gone, so there is less reason to accept the side effects of very low protein.
Where does TCM Dietetics fit?
In TCM Dietetics, a bladder with an infection and struvite in it is usually read as Damp-Heat in the Bladder. Damp is the sludge in the bottom of a water bowl that has not been scrubbed in a week. Heat is the infection. In that framework, asparagus, millet, green beans, pumpkin and peppermint are described as foods that drain Damp or cool Heat, and the first month’s recipe leaned on them.
The struvite recipe keeps the green beans and keeps the water high, and adds the mineral accounting that TCM Dietetics does not measure. The two lenses are looking at the same dog and measuring different things. The Western analysis gives me the mineral, urine and culture targets. TCM Dietetics gives me a way to think about what the food does in the body beyond those numbers. I use both.
Is the dissolution recipe the recipe for life?
No. A dissolution recipe is built for a job with an end date. The Naples authors say so directly: stop the dissolution diet once the stones are gone, because feeding it long term brings its own problems. Once the x-ray is clear, the question changes from how to dissolve the stone to why it formed.
For infection-driven struvite, preventing the next stone is mostly a question of preventing the next infection. A lifelong urinary diet is not automatically required. What he eats after the stones are gone gets decided from his stone type, his infection history, his urine findings and the rest of his health, with a repeat culture as the first check.
How will we know if it is working?
His vet runs the medical side: the culture, the antibiotic, the imaging. I run the food. Both are needed, and the trials are clear that neither one does the job alone.
Tomorrow morning his owner will hold a strip under him in the yard before breakfast, the way she has every morning for a month, and watch the square turn. The x-ray is still ahead. The strip is today.
References
Abdullahi, S. U., Osborne, C. A., Leininger, J. R., Fletcher, T. F., & Griffith, D. P. (1984). Evaluation of a calculolytic diet in female dogs with induced struvite urolithiasis. American Journal of Veterinary Research, 45(8), 1508-1519. PubMed ID 6476563.
Calabrò, S., Tudisco, R., Bianchi, S., Grossi, M., De Bonis, A., & Cutrignelli, M. I. (2011). Management of struvite uroliths in dogs. British Journal of Nutrition, 106(Suppl. 1), S191-S193. https://doi.org/10.1017/S0007114511000882
Dear, J. D., Larsen, J. A., Bannasch, M., Hulsebosch, S. E., Gagne, J. W., Johnson, E. G., & Westropp, J. L. (2019). Evaluation of a dry therapeutic urinary diet and concurrent administration of antimicrobials for struvite cystolith dissolution in dogs. BMC Veterinary Research, 15, Article 273. https://doi.org/10.1186/s12917-019-1992-8
Harris, A. S. M., Bartges, J. W., & Moyers, T. D. (2023). d,l-Methionine in combination with amoxicillin-clavulanic acid successfully dissolves spontaneously occurring infection-induced struvite urocystoliths in dogs: A pilot study. Journal of the American Veterinary Medical Association, 261(8), 1152-1159. https://doi.org/10.2460/javma.23.02.0063
Toillion, A. R., Gilyot, S., Lulich, J. P., & Furrow, E. (2026). Outcomes of medical dissolution for suspected struvite uroliths in dogs using a therapeutic multipurpose urinary diet and antimicrobial therapy. Journal of Veterinary Internal Medicine, 40(1), Article aalaf061. https://doi.org/10.1093/jvimsj/aalaf061
Wingert, A. M., Murray, O. A., Lulich, J. P., Hoelmer, A. M., Merkel, L. K., & Furrow, E. (2021). Efficacy of medical dissolution for suspected struvite cystoliths in dogs. Journal of Veterinary Internal Medicine, 35(5), 2287-2295. https://doi.org/10.1111/jvim.16252
What if the bladder is only part of it?
Struvite stones sit at the end of a longer line: the kidneys that make the urine, the gut that sets the minerals in it, and the pattern underneath both. These guides pick up where this article stops.
Your dog’s stones have their own vector
TCM Dietetics is the food side of this plan: a recipe built to hold urine pH in range, with the minerals accounted for and an x-ray at four weeks to check the work. If your dog has struvite stones and you want to cook, that is the help I offer.
Hannah Zulueta obtained her Certificate in Canine Nutrition from CASI Institute. She is also studying for her Doctorate in Acupuncture, Traditional Chinese Medicine, and Herbalism from the esteemed Pacific College of Health and Medicine. If you’re as keenly interested in health for yourself, visit her website for human health: Satori Acupuncture and Herbs.
She resides in San Diego with her three dogs, Maggie, Orbit, and Mr. Higgins.
She is available for one on one consultations. She develops evidence-based recipes that meet both NRC and AAFCO nutritional standards while integrating the therapeutic food principles of Traditional Chinese Veterinary Medicine into her formulations.
Additionally, you can find her sharing free content on Instagram.
