Updated: Dec 16, 2021
Inappropriate urination is unfortunately an increasingly more common issue in the feline population of companion animals. While there are MANY behavioral, stress and anatomical based reasons for this, diet often can be attributed to this unpleasant act as well.
In addition to inappropriate urination you may notice your cat:
Straining to pee but producing little to no urine
Many visits to the litter box
Crying when peeing
Obsessive licking of the genitals
Blood in the urine (be aware this is not always indicative of an infection which can lead to antibiotic abuse)
Comparatively, males are more likely to suffer urinary issues than females due to their anatomy. The male urethra is short and more narrow than that of the female (2, 3) cat so even though both should be on a quality species appropriate diet, males should be given special consideration.
The Problem with Dry Pet Food
Moisture in Dry Pet Food
Commercial dry food or kibble contains only 7-10% moisture. Normally this is not a problem for a living being that eats a variety of foods. Humans for example eat fruits and veggies with water content, meats, soups and other beverages loaded with moisture, but cats on a commercial dry diet are not given such luxuries and unbeknownst to many, do not drink enough water by nature.
Unfortunately this means that cats are almost in a permanent state of dehydration (4). Not only is water important for the function of various cells and processes for all living beings, it also is responsible for flushing toxins from the body through the urinary tract (5). Water content is BY FAR one of the best ways to prevent urinary tract related conditions! No matter how much access your feline friend has to water or how much you see them drink, the fact of the matter is, cats have a VERY low thirst drive. They are by nature designed to get the water content they need primarily from the prey they eat. Research shows that urine output in high moisture diets is double that of those fed a dry food diet (1, 6, 7). One way to track your companion’s urine output is with the use of clumping cat litter. Large clumps indicate your companion is producing moderate to high amounts of urine while small clumps could indicate your companion isn’t producing enough and there may be a urinary problem. One thing should be noted about water. While water is essential, the quality of the water is also important. If you have hard water or water with added vitamins and minerals this too can contribute to urinary based conditions as well (8). To learn more about water please check out Tapping into the Right Water Source
Carbohydrates in Dry Pet Food
Another concern is the high carbohydrate content of commercial dry pet foods (6). Carbohydrates include not only grains but fruits and vegetables (9). Compared to meats which increase the acidity of the stomach acid, fruits, veggies and grains decrease the acidity (10, 11).
For a carnivore this affects the body’s ability to neutralize and destroy bacteria. If this bacteria passes through the body untouched, illness and disease ensue (12, 13). Furthermore there are specific carbohydrates that are more likely to increase the alkalinity of the stomach acid such as:
Most vegetables including but not limited to spinach, carrots, broccoli, sweet potatoes, peas and pumpkin
Most fruits, including but not limited to bananas and apples
Dairy like yogurt
Beans, including but not limited to green beans and lentils
Nuts and seeds including but not limited to, pumpkin seeds, flax seeds, sesame seeds and sunflower seeds as well as their oils
Grains including but not limited to oatmeal and brown rice
Carbohydrates also increase sugars that feed bacteria. These include….
Most vegetables including but not limited to potatoes, carrots, sweet potatoes and pumpkin
Most fruits, including but not limited to apples, bananas, pineapple, watermelon and strawberries
Dairy like yogurt
Beans, including but not limited to chickpeas, lentils and soybeans
Grains including but not limited to brown and white rice, barley and corn (14)
Notice these ingredients are very common in a lot of commercial pet foods. Most even BOAST having these “awesome” ingredients. So good even YOU could eat the food.
There is a two fold issue here as well. Carbohydrates cannot be properly broken down by our obligate carnivore companion felines. Unlike other species, they do not have the proper enzymes such as amylase to utilize these ingredients. Not only is this found in minimal amounts in the pancreas but there is no carbohydrate based enzymes found in the saliva (15, 16). A very small population of pet owners exist that properly care for their companion’s teeth when on a commercial based diet. This means that carbohydrates make home on and between the teeth of our feline friends, rotting teeth and resulting in plaque and tartar build up. When these particles and bacteria dislodge they move through the body and because there are no enzymes in the mouth to break down the carbohydrates, the stomach acid is not acidic enough to destroy bacteria and there is not enough moisture to flush it out of the body. The end result can be a urinary tract infection, kidney failure, crystals and/or bladder stones (17, 18).
Protein Levels in Dry Pet Food
It is commonly seen that pet food companies create urinary based diets that restrict protein. They believe this is the best way to handle any kind of urinary condition primarily because many of the nutrients found in meat are found in the crystals and stones that form. In regards to kidney disease for example the by products of protein metabolism such as urea also have been indicated in this disease. Unfortunately this understanding primarily comes from an outdated study involving rodents (19). The study did show that protein restriction WAS necessary in rodents so while this was extrapolated to cats and dogs, a later study disproved protein restriction in carnivores was more detrimental (20, 21) .
Other findings of protein restriction found that the restriction of protein and thus phosphorus increased the absorption rate of calcium. The same study found higher levels of protein actually reduced urolith formation.
Another study published in 2002 by The American Journal of Veterinary Research found that canned food with high carbohydrate levels increased the likelihood of calcium oxalate stone formation concluding that “canned diets formulated to contain high amounts of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, and moisture and a low amount of carbohydrate may minimize the risk of CaOx urolith formation ...” (22).
If we compare these findings to current prescription diets we find that most prescription diets are restricted in protein, calcium, phosphorus, magnesium and potassium thus increasing the risk of stone formation.
Vitamins and Minerals in Dry Pet Food
Traditionally most Veterinarians and pet owners look at the nutrients in pet food in relation to the types of urinary conditions. Such nutrients include:
Magnesium Ammonium Phosphate (23)
Vitamin D (23)
Silica (24, 25)
Vitamin C (26, 27)
These vitamins and minerals can be in excess for many reasons. Some companion animals have a medical condition and can’t properly process certain nutrients, others its due to the lack of moisture in the diet and the nutrients are concentrated in the urine, some are due to elevated and excess nutrients found in the diet, others due to medications increasing vitamin and mineral secretion beyond normal values.
While most veterinarians and pet owners focus on ingredients and pH levels of urine the more important factor is to focus on the moisture available in the diet. In theory, even if a commercial dry food is balanced in nutrients, the fact that moisture only makes up 7-10% of the diet can concentrate those nutrients and due to the lack of moisture allow them to attach to tissues and other organic material preventing their expulsion from the body via the urine.
For more information on anti-nutrients in Carbohydrates check out our article Carbohydrates
Ash in Dry Pet Food
Ash also known as “incinerated residue” or “inorganic matter” are the minerals left over if a pet food product were to be incinerated in a laboratory setting. All the protein, fat and carbohydrates would be burned and the ash would be what is left behind, primarily minerals. Very similar to the cremains left behind after a cremation. Just like human cremains it is primarily calcium and phosphorus from bone content (30).
How does this relate to inappropriate urination? It was found in the 1970’s that the magnesium content in Ash contributed to urinary tract disease (previously it was thought that Ash itself was the cause)(31). Magnesium should make up 0.1% or less on a dry matter basis (32, 33); however, it should be noted that magnesium is NOT required to be listed on pet food labels (34,35).
Prescription and Vet Prescribed Pet Food
Most often when our companions are suffering inappropriate urination we seek the help of a veterinary professional and more times than not they prescribe a prescription food diet. There are renal diets for those suffering from kidney disease, urinary support diets, urinary tract health diets etc. Unfortunately, these diets are not only quite expensive and often require a prescription from your veterinarian, they are not much different than regular dry pet foods. They are loaded with carbohydrates, extremely low in moisture, they increase your companions pH numbers (the higher the number the more basic and thus less acidic the urine) and are not tested for safety or efficacy.
Broadly prescribing prescription diets can be harmful for our companion animals as well. Many diets use an acidifying agent to break up crystals however if not used properly with the proper urinary condition it can actually increase bladder inflammation and lead to the formation of other types of stones such as calcium oxalate stones (36, 37, 38, 39). Unfortunately the bigger problem here is that calcium oxalate stones cannot be corrected with diet, they must be surgically removed (40). Did you know may urinary diets should NOT be fed past a certain time frame to deal with the condition. If this is not followed which often times it’s not as many pet owners fear a relapse, serious problems can occur including kidney damage and lowering potassium levels.
Pet food manufacturers also take the cheap way out. Instead of offering canned only products which are often lower in carbohydrates and higher in meat (grains are less expensive than meat) while increasing moisture content, they opt to add acidifying agents like dl-methionine (41).
Another addition to many prescription pet foods is sodium. Instead of adding moisture or solely switching to wet pet foods, salt was added to increase thirst and thus water intake to dilute the concentrated urine. Not only is this the wrong solution, it also can cause many physiological problems. Altering sodium chloride balance can affect many processes in the body that depend on specific balances of vitamins and minerals (1,42).
Pet Food, Food or Drug?
Pet food can be divided into two categories food or drug. If the curative benefits are derived from the main ingredients in the product then the food is considered Food. If the product according to the AAFCO directly or indirectly implies a product cures a condition than it is classified as a Drug and a company is considered to making drug claims. Making drug claims is not allowed in the pet food industry unless specific criteria are met and the product is reviewed by the FDA-CVM (43, 44).
So while urinary support or renal health are not direct claims, market savvy pet food companies know when a customer reads this they are going to buy the product because their companion has failing kidneys, a history of Urinary Tract Infections, crystals, stones or any number of urinary related conditions and unfortunately most people believe that the food is meant for their companion and will fix their condition.
Prescription and Health Claiming Regulations
One thing to briefly address about Veterinarian Recommended or sold products is their regulations with the FDA and AAFCO.
While veterinarians can more accurately diagnose conditions most are not educated in animal nutrition or have only a very basic understanding of nutrition primarily provided by pet food company representatives.
These prescription diets are also not evaluated by the FDA for safety or efficacy (which is stated on their website). According to the FDA, veterinarians are typically the primary person to talk with pet owners about nutrition, perform physical exams on companion animals, diagnose illness and disease and inform pet owners how to use products. Therefore, the FDA feels a veterinarian’s oversight is the best individual to “regulate”, promote and prescribe these products.
Apparently if the product can be bought through a veterinarian and used under their direction, this qualifies the product to receive less scrutiny and are less likely to have action enforced against them if the food product makes claim to treat or prevent illness and disease (45).
In order to add “veterinarian recommended” to a label, a statistically significant survey must be conducted that surveys a number of veterinarians to support the product claim however the AAFCO does not know how many veterinarians are needed to fill out this survey to provide such statistical information... There is also no defined survey format set in place, it just needs to support the claims of the manufacturer. For a "veterinarian formulated", or "veterinarian developed" label, only one veterinarian needs to support the claim (46).
As for the FDA, there is no pre-market approval for these products. CVM GFI #55 Supportive Data for Cat Food Labels Bearing "Reduces Urinary pH Claims: Protocol Development, provides guidelines for such urinary claims however they are not legally required to be followed (47).
Any ingredient on the Generally Recognized As Safe or GRAS list including food additives don’t need any review by the FDA either.
And finally also available on the FDA website “... most complete pet food diets intended to treat or prevent a disease aren’t approved animal drugs, and without such approval, FDA considers them to be unapproved animal drugs.” (48).
There are many conditions that result from poor diet and lack of moisture including but not limited to crystals, stones, kidney failure, urinary tract inflammation and infection and blockages. While broader we can trace each back to diet and water intake there are specific issues that typically can be identified in the conditions formation and there are specific preventatives and maintenance protocols that should be taken into account.
Crystals often form when the urine is not acidic enough often a result of a low moisture and high carbohydrate based diets. They can create stones (such as struvite and calcium oxalate) that block the urethra. If severe enough these blockages can kill a cat fairly fast given most humans are unable to catch illness and disease quickly and many cats hide it extremely well.
Struvite crystals can be dissolved and be treated with diet. This includes:
-Increasing water intake
-Controlling specific vitamins and minerals fed
-Adding an acidifying agent Unlike many pet food companies do NOT increase sodium levels to increase water intake. Instead offer:
-Plenty of water bowls in numerous locations
-Invest in a water fountain
-Add natural flavors to the water Do NOT reduce high quality animal protein. While ammonium and phosphates are contained within meat, limited protein reduces the urine pH which otherwise would prevent the development of these crystals. It is low quality plant proteins we want to avoid (49). It may be important to be conscious of the proteins we use to avoid over feeding of certain minerals and vitamins but avoiding these completely would cause other issues such as increasing absorption of other detrimental nutrients, decreasing urine acidity and promoting muscle wasting.
Calcium oxalate stones occur when the urine is concentrated with calcium and oxalate (molecules that bind to calcium).
While diet cannot dissolve calcium oxalate stones and surgical intervention is required a few things can help prevent or manage the condition:
-Increase water intake
-Provide high quality animal protein
-Provide foods rich in Vitamin B6. Low levels of B6 is known to increase the prevalence of calcium oxalate stones. While this can be a result of diet it can also be a genetic condition. In addition, numerous studies show a combination of magnesium oxide, and Vitamin B6 given over 5 or more year period decreased stone development by 90% (50).
-Provide foods rich in Citrate. Citrate is a natural inhibitor of calcium oxalate stones by binding to oxalic acid. By binding in this manner the oxalate is passed through the feces and never sees the kidneys (51).
-Avoid supplemented Vitamin C as this promotes stone formation
-Avoid supplemented Vitamin D as this promotes the absorption of calcium and thus increases urinary calcium
-Avoid oxalate containing food including fruits, veggies and grains. Meat contains the lowest amounts (52).
-Do NOT eliminate calcium. While it used to be thought it was a factor in forming stones, new research shows calcium and oxalates bind and in turn REDUCES the stone formation.
-Phosphorus, Magnesium and Pyridoxine also should NOT be restricted (53).
Magnesium and pyrophosphate (compounds that contain two phosphorus atoms) both bind to oxalates thus reducing the formation of calcium oxalate stones. Restricting Phosphorus INCREASES the uptake of calcium which CAN result in stone formation.
-Do NOT increase sodium, however do not overly restrict. Too much or too little sodium can severely alter homeostasis within the body. Overall it is important to understand that consuming a diet low in protein, calcium, phosphorous, magnesium, sodium, potassium, and moisture increase the likelihood of the formation of calcium oxalate stones (36).
Typically the cause of Urate stones are unknown in most cats other than knowing the stones are made up of an aggregate of mineral crystals that are formed in multiple locations of the urinary tract (54). However there are some breed specific connections (55).
-Increase water intake Do NOT reduce protein. Often those with Urate Stones are recommended to have a low purine diet. Purines are chemical compounds that form uric acid when oxidized. They are produced in the body naturally but also can be found in meat, fruits and vegetables. Many believe this means you shouldn’t feed protein at all.
Reduce purine heavy foods. Purine bases notable for this condition include adenine, guanine, hypoxanthine and xanthine however there are enzymes for each purine base that can help to properly break them down since the liver can't. Enzymes include Xanthine oxidase to oxidize hypoxanthine, xanthine, adenine, and guanine while guanase converts guanine to xanthine.
For humans it is recommended to consume less than 400 mg of total purines per day and be especially mindful of hypoxanthine which has the greatest effect on uric acid levels while guanine has been reported to have the least effect on uric acid levels (56).
Limit the red meats fed and stick more to white meats Supplement carnitine (57)
Several breeds of cats (and dogs) are predisposed with several types of cystine stones forming.
While more rare in cats it is a congenital condition which can be genetically tested for (58).
These stones often a result of a dysfunction in the renal transportation of the amino acids, cystine, ornithine, lysine, and arginine in numerous locations of the urinary tract. Another factor is alkaline urine (59).
While cystine stones are genetic, diet cannot dissolve these stones but there are some things diet wise that can help prevent or reduce the prevalence of them.
While there are many veterinarians who suggest alkalinizing urine do NOT alkalinize urine as this can cause stones we don’t want to form. Even in those patients where urine was alkalinized, stone formation often was not prevented (59, 60).
Do NOT restrict protein. Cystine is present in meat, however restricted meat in obligate carnivores can cause extreme health issues and many have found despite restriction, stones still form.
To learn more about different crystal types and diet check out THIS article.
Kidney failure aside from urinary tract infections is one of the most common conditions of domestic felines. This is often due to lack of moisture in the diet as well as the carbohydrate load in most pet foods that heavily tax our carnivore companions kidneys’.
-Increase water intake -Eliminate carbohydrates from the diet (fruits, veggies and grains)
-Reduce phosphorus intake, for a raw diet this means replacing bone with eggshell
-Do NOT restrict protein. It promotes muscle wasting and progresses kidney disease
To learn more about kidney disease check out our article Failing Filtration.
What CAN you do?
Emergency and even basic care for an animal with urinary issues is quite expensive not only considering the immediate medical care required but the high chances of relapse and maintenance thereafter. There are many things you can do to prevent (in most cases) urinary based issues.
If you are a breeder, genetically test your breeding cats to avoid genetic based urinary conditions.
As pet owners and breeders feed a species appropriate raw diet from the start. This means feeding a rotation of meat, organs and bones from several protein sources, no carbohydrates (fruits, veggies and grains) unless it’s included in whole prey and provide plenty of water to maintain proper water intake.
If your companion does develop crystals, stones or other urinary issues PRIOR to raw feeding, switch to raw feeding following the suggestions above depending on the individual circumstance.
If your companion does develop crystals, stones or other urinary issue WHILE feeding raw CONTINUE to feed raw. It is still the most beneficial diet for your companion. Reevaluate what you are feeding specifically to make adjustments as noted above and consider alternative factors that may be causing the urinary issues such as genetics, behavior or individual anatomy of your companion.
In addition to being aware of what you are feeding, tracking urine pH can be very important to determine what proteins and ingredients influence your felines urine output and pH levels. Be aware of when testing occurs in relation to meal intake for example large meals are followed by a “Post-prandial alkaline tide” meaning the pH will be more alkaline right after a large meal. Therefore increasing the number of meals throughout the day may help regulate pH levels better.
Also be aware of the medications you are being prescribed or given to your companions. Certain medications can influence pH or cause certain stone and crystal causing minerals and vitamins to be excreted more readily (1).
D-mannose is a simple sugar found in cranberries and other fruit that can be added to the diet in appropriate doses and duration to prevent the adherence of bacteria to the urinary tract.
Omega 3s can also aid in urinary conditions by reducing inflammation (61, 62, 63, 64).
Adding freeze dried lactic acid bacteria such as Lactobacillus acidophilus, L. plantarum, L. brevis, Streptococcus thermophilus and Bifidus infantis have been shown to reduce calcium oxalate stones (65, 66).
These are just some general suggestions for preventing and managing urinary conditions such as crystals, stones, blockages, kidney disease and more. While diet plays a huge role in urinary conditions there are still other possibilities to explore when dealing with inappropriate urination. To explore these topics please check out our articles Why is my Cat Inappropriately Peeing? Behavior Edition and Why is my Cat Inappropriately Peeing? Medical Edition.
Just a friendly reminder while our background and degree is in the animal sciences and we do extensive scientific research on each topic we are not veterinary school certified nutritionists. Please do not use this blog to diagnose your companion animal. Raw Vibes and its information including this text is not intended to replace a veterinarian but only to provide an avenue to educate. Raw Vibes is not responsible for companion pets that are ill. We assume no responsibility or liability for the use of the information contained in this text. If you have any concerns about your dog or cat’s health, please contact your holistic veterinarian or other qualified professional immediately.
1. Pierson, Lisa A. “Cat Urinary Tract Diseases: Cystitis, Urethral Obstruction, Urinary Tract Infection.” Cat Info, Dec. 2016, catinfo.org/feline-urinary-tract-diseases/.
2. Wang, Baoqing, et al. “FUNCTIONAL ANATOMY OF THE MALE FELINE URETHRA: MORPHOLOGICAL AND PHYSIOLOGICAL CORRELATIONS.” The Journal of Urology, No Longer Published by Elsevier, 14 Nov. 2005, www.sciencedirect.com/science/article/abs/pii/S002253470161989X.
3. Shaw D, Ihle S. Urinary tract disease and fluid and electrolyte disorders. In: Small Animal Internal Medicine. Baltimore, MD: Williams & Wilkins; 1997:323-377
4. National Research Council. 2006. Nutrient Requirements of Dogs and Cats. Washington, DC: The National Academies Press. https://doi.org/10.17226/10668..
5. Hodgkins, Elizabeth M. Your Cat: A Revolutionary Approach to Feline Health and Happiness. 1st ed., Thomas Dunne Books, 2007..
6. Funaba, Masayuki, et al. “Evaluation of Effects of Dietary Carbohydrate on Formation of Struvite Crystals in Urine and Macromineral Balance in Clinically Normal Cats.” American Journal of Veterinary Research, U.S. National Library of Medicine, Feb. 2004, www.ncbi.nlm.nih.gov/pubmed/14974568?dopt=Abstract.
7. Tarttelin, M F. “Feline Struvite Urolithiasis: Factors Affecting Urine PH May Be More Important than Magnesium Levels in Food.” The Veterinary Record, U.S. National Library of Medicine, 5 Sept. 1987, www.ncbi.nlm.nih.gov/pubmed/3672831?dopt=Abstract.
8. Peyton, et al. “Trupanion Trends: Study Finds Link between Pet Health and Drinking Water.” Trupanion Pet Care, 7 Apr. 2016, trupanion.com/blog/2016/04/trupanion-trends-hard-water-pet-urinary-health-study/
9. Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med. 2011;364:2392-404.
10. Beasley, DeAnna E. et al. “The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome.” Ed. Xiangzhen Li. PLoS ONE 10.7 (2015): e0134116. PMC. Web. 14 July 2018.
11. Tobey, J A. “The Question of Acid and Alkali Forming Foods.” American journal of public health and the nation's health vol. 26,11 (1936): 1113-6. doi:10.2105/ajph.26.11.1113
12. Claudia Ugarte, W. Grant Guilford, Peter Markwell, Evelyn Lupton; Carbohydrate Malabsorption Is a Feature of Feline Inflammatory Bowel Disease but Does Not Increase Clinical Gastrointestinal Signs, The Journal of Nutrition, Volume 134, Issue 8, 1 August 2004, Pages 2068S–2071S, https://doi.org/10.1093/jn/134.8.2068S
13. Bardin, Stefani. “2011 TEDxManhattan Fellow: Artist Stefani Bardin.” YouTube, YouTube, 19 Sept. 2015, www.youtube.com/watch?v=lLPfCfdQfPY.
14. Atkinson, Fiona S, et al. “International Tables of Glycemic Index and Glycemic Load Values: 2008.” Diabetes Care, American Diabetes Association, Dec. 2008, www.ncbi.nlm.nih.gov/pmc/articles/PMC2584181/.
15. Kienzle E. 1993. “Carbohydrate metabolism of the cat. 1. Activity of amylase in the gastrointestinal tract of the cat.” J. Anim. Physiol. Anim. Nutr. (Berl.) 69:92–101.
16. Verbrugghe, Adronie, and Myriam Hesta. “Cats and Carbohydrates: The Carnivore Fantasy?” Ed. Jacquie Rand.
17. Hofve, Jean. “Digestive Enzymes.” IVC Journal, IVC Journal, 10 Aug. 2017, ivcjournal.com/digestive-enzymes/.
18. Lonsdale, Tom. Raw Meaty Bones: Promote Health. Rivetco P/L, 2001.
19. Yu, B P, et al. “Nutritional Influences on Aging of Fischer 344 Rats: I. Physical, Metabolic, and Longevity Characteristics.” Journal of Gerontology, U.S. National Library of Medicine, Nov. 1985, www.ncbi.nlm.nih.gov/pubmed/4056321.
20. Robertson, John L., et al. “Long-Term Renal Responses to High Dietary Protein in Dogs with 75% Nephrectomy.” Kidney International, Elsevier, 18 Dec. 2015, www.sciencedirect.com/science/article/pii/S0085253815336127.
21. Bovée, K C, et al. “Long-Term Measurement of Renal Function in Partially Nephrectomized Dogs Fed 56, 27, or 19% Protein.” Investigative Urology, U.S. National Library of Medicine, Mar. 1979, www.ncbi.nlm.nih.gov/pubmed/429135.
22. Lekcharoensuk, Chalermpol, et al. “Associations between Dry Dietary Factors and Canine Calcium Oxalate Uroliths.” American Journal of Veterinary Research, U.S. National Library of Medicine, Mar. 2002, www.ncbi.nlm.nih.gov/pubmed/11911566.
23. “FELINE CALCIUM PHOSPHATE.” UNIVERSITY OF MINNESOTA, Https://Www.vetmed.umn.edu/Sites/Vetmed.umn.edu/Files/feline_calcium_phosphate_uroliths.Pdf, www.vetmed.umn.edu/sites/vetmed.umn.edu/files/feline_calcium_phosphate_uroliths.pdf.
24. Tanaka, H. 1995. Expectations for development of medicine based on biological function of trace metals, pp.3–12. In: Biological activity of trace metals (The Chemical Society of Japan, eds.), Japan Scientific Societies Press, Tokyo (in Japanese with English abstract).
25. Takahashi, Fumihito, et al. “The Silicon Concentration in Cat Urine and Its Relationship with Other Elements.” The Journal of Veterinary Medical Science, The Japanese Society of Veterinary Science, Apr. 2014, www.ncbi.nlm.nih.gov/pmc/articles/PMC4064144/.
26. Hellman, L., et al. “Ascorbic Acid Intake and Oxalate Synthesis.” Urolithiasis, Springer Berlin Heidelberg, 1 Jan. 1970, link.springer.com/article/10.1007/s00240-016-0868-7.
27. Assimos, Dean G. “Vitamin C Supplementation and Urinary Oxalate Excretion.” Reviews in Urology, MedReviews, LLC, 2004, www.ncbi.nlm.nih.gov/pmc/articles/PMC1472830/.
28. Mochizuki, Mariko, et al. “The Distribution of Several Elements in Cat Urine and the Relation between the Content of Elements and Urolithiasis.” Biological Trace Element Research, U.S. National Library of Medicine, Nov. 2011, www.ncbi.nlm.nih.gov/pubmed/21057890 dopt=Abstract.
29. Mochizuki, Mariko, et al. “The Distribution of Several Elements in Cat Urine and the Relation between the Content of Elements and Urolithiasis.” Biological Trace Element Research, U.S. National Library of Medicine, Nov. 2011, www.ncbi.nlm.nih.gov/pubmed/21057890?dopt=Abstract.
30. Fascetti, A.J and Delaney, S.J (2012) Applied Veterinary Clinical Nutrition, Chichester: Wiley Blackwell.
31. Blount, W.P. “Urinary Calculi.” The Veterinary Journal (1900), W.B. Saunders, 4 Sept. 2017, www.sciencedirect.com/science/article/pii/S0372554517401064.
32. Buffington CA Acid questions potential dangers associated with cat food acidification pet food ind 4-8 1983 Tijdschr Diergeneeskd. 1986 May 15;111(10):476-9.
33. Burger, I H. “Nutritional Aspects in Relation to the Feline Urological Syndrome (FUS).” Tijdschrift Voor Diergeneeskunde, U.S. National Library of Medicine, 15 May 1986, www.ncbi.nlm.nih.gov/pubmed/3520944.
34. “Nutritional Labeling.” The Association of American Feed Control Officials (AAFCO) > Home, 2012, petfood.aafco.org/Nutritional-Labeling.
35. “Reading Labels.” The Association of American Feed Control Officials (AAFCO) > Home, 2012, talkspetfood.aafco.org/readinglabels.
36. Lekcharoensuk C, Osborne CA, Lulich JP, et al. Association between dietary factors and the risk of calcium oxalate and magnesium ammonium phosphate urolithiasis in cats. JAVMA 2001;219:1228–1237. 59.
37. Lekcharoensuk C, Osborne CA, Lulich JP, et al. Associations between dry dietary factors and canine calcium oxalate uroliths. Am J Vet Res 2002;63:330–337.
38. Kirk CA, Ling GV, Franti CE, Scarlett JM. Evaluation of factors associated with development of calcium oxalate urolithiasis in cats. J Am Vet Med Assoc 1995;207:1429–1434.
39. Okafor CC, Lefebvre SL, Pearl DL. Risk factors associated with calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States. Prev Vet Med 2014;115:217–228
40. Lulich, J P, et al. “ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats.” Journal of Veterinary Internal Medicine, John Wiley and Sons Inc., Sept. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC5032870/pdf/JVIM-30-1564.pdf.
41. Funaba, M, et al. “Effect of Supplementation of Dry Cat Food with D,L-Methionine and Ammonium Chloride on Struvite Activity Product and Sediment in Urine.” The Journal of Veterinary Medical Science, U.S. National Library of Medicine, Mar. 2001, www.ncbi.nlm.nih.gov/pubmed/11307939.
42. Dow, S W, et al. “Effects of Dietary Acidification and Potassium Depletion on Acid-Base Balance, Mineral Metabolism and Renal Function in Adult Cats.” The Journal of Nutrition, U.S. National Library of Medicine, June 1990, www.ncbi.nlm.nih.gov/pubmed/2352031?dopt=Abstract.
43. Medicine, Center for Veterinary. “Pet Food.” U.S. Food and Drug Administration, FDA, 4 June 2019, www.fda.gov/animal-veterinary/animal-food-feeds/pet-food.
44. “Marketing & ‘Romance’ Claims.” The Association of American Feed Control Officials (AAFCO) > Home, 2012, petfood.aafco.org/Marketing-Romance-Claims.
45. “Guidance for FDA Staff Compliance Policy Guide Sec. 690.150 Labeling and Marketing of Dog and Cat Food Diets Intended to Diagnose, Cure, Mitigate, Treat, or Prevent Diseases.” Food and Drug Administration , Apr. 2016, www.fda.gov/media/83998/download.
46. “Labeling & Labeling Requirements.” The Association of American Feed Control Officials (AAFCO) > Home, 2012, petfood.aafco.org/Labeling-Labeling-Requirements#vet_r.
47. Medicine, Center for Veterinary. “CVM Guidance for Industry #55.” U.S. Food and Drug Administration, FDA, June 1994, www.fda.gov/regulatory-information/search-fda-guidance-documents/cvm-gfi-55-supportive-data-cat-food-labels-bearing-reduces-urinary-ph-claims-protocol-development.
48. Medicine, Center for Veterinary. “Pet Food.” U.S. Food and Drug Administration, FDA, 4 June 2019, www.fda.gov/animal-veterinary/animal-food-feeds/pet-food.
49. Gardiner, John. “Nutritional Management of Uroliths.” School of Veterinary Medicine, 22 June 2018, www.vetmed.ucdavis.edu/hospital/animal-health-topics/uroliths.
50. Gershoff, S N, and E L Prien. “Effect of Daily MgO and Vitamin B6 Administration to Patients with Recurring Calcium Oxalate Kidney Stones.” The American Journal of Clinical Nutrition, U.S. National Library of Medicine, May 1967, www.ncbi.nlm.nih.gov/pubmed/6023850.
51. O'Kell, Allison L, et al. “Pathogenesis of Calcium Oxalate Urinary Stone Disease: Species Comparison of Humans, Dogs, and Cats.” Urolithiasis, U.S. National Library of Medicine, Aug. 2017, www.ncbi.nlm.nih.gov/pmc/articles/PMC5511574/.
52. “Low Oxalate Diet.” PK Diet, University of Pittsburgh Medical Center, 2003, www.pkdiet.com/pdf/LowOxalateDiet.pdf.
53. Elliott, Denise A. “Managing Calcium Oxalate Urolithiasis in Cats - WALTHAMTNAVC2003 - VIN.” Powered By VIN, Waltham Feline Medicine Symposium 2003, 2003, www.vin.com/apputil/content/defaultadv1.aspx pId=11154&id=3847272.
54. FELINE URATE.” UNIVERSITY OF MINNESOTA, https://www.vetmed.umn.edu/sites/vetmed.umn.edu/files/feline_urate_uroliths.pdf
55. Appel, Sherry L, et al. Feline Urate Urolithiasis. CVJ, May 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2857427/pdf/cvj_05_493.pdf.
56. Kaneko, Kiyoko, et al. “Total Purine and Purine Base Content of Common Foodstuffs for Facilitating Nutritional Therapy for Gout and Hyperuricemia.” Biological & Pharmaceutical Bulletin, U.S. National Library of Medicine, 2014, www.ncbi.nlm.nih.gov/pubmed/24553148.
57. Volek, Jeff S, et al. “L-Carnitine L-Tartrate Supplementation Favorably Affects Markers of Recovery from Exercise Stress.” American Journal of Physiology. Endocrinology and Metabolism, U.S. National Library of Medicine, Feb. 2002, www.ncbi.nlm.nih.gov/pubmed/11788381.
58. Mizukami K, Raj K, Giger U (2015). Feline Cystinuria Caused by a Missense Mutation in the SLC3A1 Gene. J Vet Intern Med 29(1): 120-125. doi: 10.1111/jvim.12501
59. Byron, Julie. “Crystals, Stones and Diets, OH MY!” Pennsylvania Veterinary Medical Association, 2018, cdn.ymaws.com/www.pavma.org/resource/resmgr/docs/kvc/2018/byron,_julie/5._crystals,_stones,_and_die.pdf.
60. Keith, Christie. “Canine Cystinuria: B-Naturals.Com Newsletter.” B-Naturals, 15 Oct. 2009, www.b-naturals.com/newsletter/canine-cystinuria/.
61. Burns, Kara M. “Nutrient Strategies for Managing Those (FIC)Kle FLUTD Cases.” DVM 360, 30 Nov. 2018, www.dvm360.com/view/nutrient-strategies-managing-those-fickle-flutd-cases.
62. Calder, PC. “n-3 Polyunsaturated Fatty Acids, Inflammation, and Inflammatory Diseases.”PubMed.gov, Am J Clin Nutr., June 2006, www.ncbi.nlm.nih.gov/pubmed/16841861.
63. Syren, M L, et al. “The Polyunsaturated Fatty Acid Balance in Kidney Health and Disease: A Review.” Clinical Nutrition (Edinburgh, Scotland)., U.S. National Library of Medicine, 6 Dec. 2017, www.ncbi.nlm.nih.gov/pubmed/29254659.
64. Zanetti, M.; Gortan Cappellari, G.; Barbetta, D.; Semolic, A.; Barazzoni, R. Omega 3 Polyunsaturated Fatty Acids Improve Endothelial Dysfunction in Chronic Renal Failure: Role of eNOS Activation and of Oxidative Stress. Nutrients 2017, 9, 895.
65. Okombo, Joseph, and Michael Liebman. “Probiotic-Induced Reduction of Gastrointestinal Oxalate Absorption in Healthy Subjects.” Urological Research, U.S. National Library of Medicine, June 2010, www.ncbi.nlm.nih.gov/pubmed/20224931.
66. Al-Wahsh, Ismail, et al. “Acute Probiotic Ingestion Reduces Gastrointestinal Oxalate Absorption in Healthy Subjects.” Urological Research, U.S. National Library of Medicine, June 2012, www.ncbi.nlm.nih.gov/pubmed/21874572.