Veterinary-grade urinary care cat food works to a certain extent so you can’t call it a scam. However, it is a relatively poor solution to the formation of crystals of magnesium ammonium phosphate (“struvites” or cat crystals) in the bladder causing a urinary blockage. The conclusion and the answer to the question is that specialist dry cat foods are not a scam but they are less effective than reverting to a more natural wet, meat-based diet which can be found in a high quality wet cat food. Also ensuring a cat drinks well is important (adding water to the food?)
Cereal-based foods lead to higher pH
I think it’s worth briefly looking at the history of cat food to get to the bottom of the answer. Back in the old days when dry cat food wasn’t around and even in the days when cats were fed human foods, urinary tract crystals weren’t a problem like they are today. In the 1970s and 1980s veterinarian started to see large numbers of cases of cystitis, bladder crystal and stone formation. The rise in these urinary tract problems coincided with the increase in the use of dry kibble.
The scientists at the commercial cat food manufacturers got wind of this and decided to fix the problem by modifying their cat food. They could not, after all, do away with this profitable product. As the crystals were formed of magnesium salts they decided that the magnesium in the foods caused the crystals. They also knew that magnesium crystals form in alkaline urine but not acid urine. They therefore added acid to the food which is what these prescription diet urinary tract foods contain. They have been partially successful but crystals of a different sort made up of calcium oxalate might form because the urine is too acidic.
An example of the success of these sorts of specialist dry cat foods can be found on the quora.com website. Lottie Mills says that her boy cat suffered repeatedly with struvite crystals and a prescription urinary diet certainly helped him. So they can help but in my view they are modifications of an inherently unhelpful product.
What the commercial cat food manufacturers did not (or refused to) consider at the time was that the cereal-based, high carbohydrate, dry foods were the cause. Dry cat foods encourage the production of crystals because it is cereal-based which results in a slightly alkaline or neutral urine. Also as the domestic cat is a rather poor drinker of water because of their wild cat heritage, the cat’s thirst drive is poor which leads them to not drinking enough water to compensate for their dry diet.
Rather than modifying an inherently slightly defective diet which dry cat food is they should have come to the conclusion that a more natural meat-based wet food diet would be the best solution. But, as mentioned, they could not take that option because it would’ve removed a significant part of their product range.
However, they were right in saying that a relatively high pH diet encourages the formation of struvite stones in the urinary tract. In fact a researcher, Dr Tony Buffington, in 1985, figured that there is an optimum pH range of 5.6 to 6.4 for cat food. If it’s too high i.e. too alkaline, crystals form and if it’s too low i.e. too acidic it could start dissolving bone, he said.
Males versus females
Another aspect of this disease is that both males and females get it but blockages don’t form in a female’s urinary tract because of their anatomy. That’s why in the past, veterinary surgeons developed a surgical procedure in which the male cat urethra is amputated to allow urine with crystals to flow from the bladder to the exterior. It appears that those invasive surgeries could have been avoided.
Dr Buffington describes the end of a male’s urinary tract as like a “fire hose nozzle” designed to spray which is predisposed to a blockage. Also the disease itself can cause scarring of the tissue which can further exacerbate the potential for blockage.
It should also be noted that if a blockage of the urinary tract is not dealt with promptly it can kill a cat through uremic poisoning which is poisoning of the body because of waste products circulating throughout the body.
It is said that feline urological syndrome (FUS – problems associated with the cat’s bladder and urinary tract) is possibly the most common single cause for a cat’s admission to veterinary hospital. A study concluded that FUS affected 21.5% of male cats and 13.5% of all cats. Admissions to hospital were at 9.8% for males and 2.3% for females.