Help Please, cat with FLUTD.

 I just asked this question in a vet email group I belong to, here's the answer (goes to dig it up):

The most common crystal in the urine are struvite crystals. Struvites are made up of calcium, magnesium and
phosphorus. The kidneys normally excrete these minerals. Normal cat urine is slighty acidic (ph aproximately 6.5). But when cat urine
becomes alkaline (pH>7) these crystals can come together and form little stones. When this happens, male cats get blocked up and
female cats strain to urine.

Did your vet mention what your kitty cat's urine pH was?

Hills S/D is an acidifying diet (it makes the urine very acid) to dissolve small stones and prevent crystals from forming. It is also
low in magnesium (one of the building blocks of struvite--> therefore reducing the chance that stones will form.

Now, S/D is not a balanced diet--it is too acidifying and it too low in protein, so it can only be fed for a maximum of three months. I
usually convert these cats over to C/D which is the long term maintence diet.

C/D has recently been reformulated. It still has reduced levels of Magnesium and Phosphorus, but also contains increased levels of
Omega 3 Fatty Acids to reduce inflammation to help the bladder to heal.

If you do not want to feed Hills--talk to your vet about feeding the Merrick BID, and giving D-L methinine (the amino acid that acidifies
urine--it comes in tablet or paste forms and maybe powder?) and adding fatty acids to his diet. It isn't perfect and personally I
would prefer you feed one of the prescription diets, but if you are motivated to medicate your kitty cat (and your kitty cat is
cooperative) and your vet is willing to working with you--maybe something can be worked out.

GOOD LUCK,

Beth DVM

Basically after reading this, talking to my vet along with a vet friend of mine, the gist is that it helps balance the pH which keeps crystals from forming. I am currently looking for an alternative to CD (which is what my cat is on). I've heard things about Wellness (there's a formula for urinary tract health) and regular Science diet and Purina pro plan, of all things. I think that you take a chance any way you go about it to see what works. Canned food though is a must from what everyone has said.

P.S. another tip I got was to have your cat drink distilled water instead of water out of the tap. My tap water, in particular, has a very high pH (I know this because of my hot tub).
 

Gosh, I'm sorry -- I'm just not cat-saavy at all.  Have they actually had a urinalysis done?  If there are struvite crystals (or that high PH she mentioned) then an acidifying diet is important.  What she COULD do is contact someone like Doggie Dietician (Monica Segal -- http://www.monicasegal.com -- and I think she does cats as well as dogs).  Any canned diet can be mimicked by a homecooked diet -- cats are obligate carnivores so it's a matter of finding the appropriate protein amount to feed and adding acid to it -- which can be done by adding ascorbic acid (a specific form of Vit C) which STAYS acidic thru the body's processes. 

Cranberry is more for uti's -- it's mostly glucose which bonds to infection cells and makes them too slippery to stay in the urinary tract.  But if crystals are the problem then cranberry's not going to help -- it's very minorly acidic really. 

The other good alternative would be to find a holistic vet that does acupuncture (which is going to help with any and all renal issues) and can help guide diet-wise.  http://www.tcvm.com -- on the left is a locator that will help you find a practitioner near where these folks live.