There are no guarantees, but some people do swear by certain diets.
You could try the SCD (specific carbohydrate diet) developed for people with Crohn's and UC, and is based on what was the original diet for people with Celiac's disease...no grains, no sugar (but honey is OK), no fluid milk (but aged cheese and homemade yogurt is OK), no processed foods (hot dogs, but meats, fish, poultry, eggs are OK), fresh or frozen fruits and vegies are OK (but not canned). At www.breakingtheviciouscycle.info you can find out more info about this diet. If you check out the book, "Breaking the Vicious Cycle" on the Amazon web site, you will see a lot of testimonials for SCD. It's a healthy way of eating, and might be worth a try.
Some people swear by the Maker's Diet, which is similar to the SCD diet.
I wish I had known about these diets before my daughter was put on meds.