struvite crystals which form in urine with elevated pH (>6.8, even more likely with continued levels above 7.0)
calcium oxalate crystals which form in too acidic urine (<6.0)
(1) alkaline urine and
(2) Concentrated urine
Couch Grass Root - loose dried form or powdered (in bulk section or capsules)
Cornsilk – loose dried form or powdered (in bulk section or capsules)
Marshmallow root OR Slippery Elm Bark – loose dried form or powdered (in bulk section or capsules)
Vitamin C (500- 1,000 mgs a day) – only in acute stage (and only for cats who do not have CRF or any other condition contributing to metabolic acidosis) because in times of stress Vit C levels can decline. All other times, it's debatable if cats need Vitamin C because cats produce Vitamin C. Note: there is no reliable evidence at this time to count on Vitamin C acidifying urine.
Glucosamine Sulfate and Chrondroitin Sulfate: acute stage 500mg daily, then 250 mg intermediate healing stage, and 125 mg longer-term (if needed).
Glucosamine sulfate has anti-inflammatory action and also helps rebuild/support the protective mucosal surface/GAG layer of the bladder. So it helps with bladder spasms. Chondroitin sulfate keeps the GAG layer from being broken down so it's more of a defense player whereas Glucosamine plays offense
Notes and References
Silver-Colloids site reporting efficacy against e. coli, Pseudomonas aeruginosa, and Enterococcus faecalis.
D-Mannose summaries, about the most scientific I could find
In these 2 chapters from the same textbook, there is mention of the fact that "bacterial urinary tract infections are reported to occur in 2 to 3% of dogs and in less than 1% of cats" with Escherichia coli bring the most common:
Lulich JP, Osborne CA, Bartges JW, et al. Canine lower urinary tract disorders In: Ettinger SJ,Feldman EC, eds. Textbook of veterinary internal medicine. 5th ed. Philadelphia: WB Saunders, 1999.
Osborne CA, Kruger JM, Lulich JP, et al. Feline lower urinary tract diseases In: Ettinger SJ,Feldman EC, eds. Textbook of veterinary internal medicine. 5th ed. Philadelphia: WB Saunders, 1999
Very comprehensive notes from a vet school; includes results from Buffington et al's JAVMA paper and magnesium-pH info Discusses various urinary conditions and research findings related to FUS/FLUTD issues including this one from Buffington - 65.4% of the 109 cats in the sample had idiopathic cystitis (IC)
These researchers found that a high-protein (55% i.e. close to a mouse's protein level) diet "is preferable as a urine acidifier for the prevention of struvite crystal formation in clinically normal cats":
Am J Vet Res. 2003 Aug;64(8):1059-64. Effects of a high-protein diet versus dietary supplementation with ammonium chloride on struvite crystal formation in urine of clinically normal cats. Funaba M, Yamate T, Hashida Y, Maki K, Gotoh K, Kaneko M, Yamamoto H, Iriki T, Hatano Y, Abe M. Laboratory of Nutrition, Azabu University School of Veterinary Medicine, 1-17-71 Fuchinobe, Sagamihara 229-8501, Japan.
Study showing that high starch and fiber levels in diets promote struvite crystals formation. Plug in this Pubmed #: 14974568 if the link doesn't work: http://www.ncbi.nlm.nih.gov/sites/entrez
"Evaluation of effects of dietary carbohydrate on formation of struvite crystals in urine and macromineral balance in clinically normal cats.", Funaba M, Uchiyama A, Takahashi K, Kaneko M, Yamamoto H, Namikawa K, Iriki T, Hatano Y, Abe M. Am J Vet Res. 2004 Feb;65(2):138-42.
Mixed results for cranberry in this one – urine pH went up in fresh urine:
"Cranberry juice and its impact on peri-stomal skin conditions for urostomy patients." Tsukada K, Tokunaga K, Iwama T, Mishima Y, Tazawa K, Fujimaki M., Ostomy Wound Manage. 1994 Nov-Dec;40(9):60-2, 64, 66-8.
"Small adrenal glands in cats with feline interstitial cystitis", Westropp JL, Welk KA, Buffington CA., J Urol. 2003 Dec;170(6 Pt 1):2494-7.
"Clinical efficacy of L-theanine tablets to reduce anxiety-related emotional disorders in cats: A pilot open-label clinical trial", V. Dramard, L. Kern, J. Hofmans, C. Halsberghe, and C.A. Rème, Journal of Veterinary Behavior, Volume 2, Issue 3, Pages 85-86 (May 2007)