What food for sensitive dog, and cat with cystitis

Our customer asked:

I am in the middle of placing an order but am not sure which product would be best for my dog and cats need. My dog is prone to gut problems. He tends to suffer slight bloat but is still able to expel excess wind without any problems. He also brings up bile on a daily bases. There is no retching and he simply burps up bile. I wanted to know the best product to help with this.
My cat also has bouts of feline cystitis and wondered if there was any non-prescription supplements that would reduce the amount of flare ups and help to keep him more comfortable?

Our reply:

I personally would try your dog on a higher protein, lower carbohydrate diet. It might help to be fish or chicken based. I would suggest Barking Heads Sensitive, or Barking Heads Salmon and Potato diet.

Your cat should definitely be on a wet, not dried food if possible. (If your cat produces dilute urine consistently, the cystitis may never recur. This means a higher fluid intake, which is best achieved with a (more natural) wet diet. Tinned or pouched food is fine. There are supplements to be used (such as Cystophan) but in fact they do not work unless given every day, they take a while to start to have any effect, and the wet food is just as effective (a nuisance to give though, compared with dried diets.)