Crystal diet question

Dear Dogs Today,
I recently noticed to my horror that one of my dogs had blood in his urine. Armed with a sample of his urine, I took him to see my vet. I was hoping that it was just going to be an infection, curable with antibiotics. However, my vet tested a couple of urine samples and confirmed that crystals were to blame. He is going to have to be on a prescription diet for 6 weeks, and then re-assessed. This will be difficult as I have two other dogs, but I'm not complaining, I'm very grateful that this is available to me.
Graham is a 4 year old Jack Russell. We rescued him two years ago (he was featured in your 'Good Boy Awards' in July last year!) He is in excellent health apart from this recent problem, and I'd like to know what has caused it. The main part of all my dogs' diet is raw chicken, they sometimes have a tin of good quality dog food if I have been unable to get fresh chicken, and they do also have Bonios and Frolics as treats. They always have plenty of fresh water available to them. As I said, they are all in fantastic condition, they're super fit, happy, shiny and beautiful! Are some dogs just 'prone' to this problem, as I believe some people are? I was wondering also, if Graham's 'bad' diet in his first home might have anything to do with it? Assuming that this problem will be a reoccurring one, can I continue to feed the raw chicken, or does feeding a prescription diet mean at the exclusion of everything else?
Thank you very much for your time and valued opinion,
Yours Sincerely
Sara Marlow

The presence of crystals in the urine is something that causes a great deal of confusion, even (dare I say it) amongst vets. Let’s get this straight once and for all. Just because crystals are found in urine does NOT mean they are necessarily causing any problems. Let me quote from the Merck Veterinary Manual, one of the veterinary ‘bibles’:
‘Many urine sediments contain crystals. The type of crystal present depends on urine pH, concentration of crystallogenic materials, urine temperature and length of time between urine collection and examination.'
‘Struvite crystalluria in dogs is not a problem unless there is a concurrent bacterial urinary tract infection with a urease-producing microbe.'
What this is saying, in brief, is that crystals form for various reasons, and the numbers present depend on many factors (the older the sample before testing, the more crystals are likely to be seen, for example). The most common crystal type, struvite, is NOT a problem unless infection is present.
Without knowing exactly which type of crystals your Jack Russell was found to have, and how many, and how long after the sample was taken it was tested, and so on, I can’t be sure how significant the presence of crystals really is, but the crystals may well not be as worrying as has been suggested.
Raw food diets do not normally encourage crystal formation in my experience, however some water supplies are quite high in minerals that could predispose to crystals, and it might be worthwhile changing to distilled water (not mineral water which as the name suggests is high in minerals). Supplements such as cranberry juice or powder can encourage the production of urine with a higher acidity that will reduce the likelihood of infections and other urinary problems.
I would suggest you follow this up with your vet and ask for more details about the type and numbers of crystals and discuss whether the use of a prescription diet is really warranted. I would be very surprised if there were any need to feed this long-term and I hope and expect Graham can be back enjoying his raw chicken wings very shortly!
Richard Allport, alternative vet