This may be worth a try. Everyone’s different, but many have had UC had their symptoms reduced or cleared by the starch-based plant diet approach (Dr John McDougall, Santa Rosa CA), i.e. starch (rice, oats, sweet potato, corn etc) so you don’t go hungry, and lots of cooked or raw veg greens, plus some fruits. Try for 30-days, leaving out the meats, oil, dairy, cheese, and cholesteral laden foods.
I had UC decades ago. Signs of prior UC scarring or polyps never completely cleared until I switched to this nutritional approach. A few years after the dietary change, there were zero signs of prior UC, just a shiny smooth colon.
A simplistic explanation is that the body’s autoimmune attacks your own cells that look like foreign cells, i.e. meat proteins. It seems less likely the body would attack the intestinal linings with invading plant cells in your diet! My gastro doc agreed the diet could be causative — but only after 20 years of denying diet had any effect (they’d lose business!). But he didn’t like my explanation, not do they teach nutrition vs UC in med school — preferring expensive pills and surgery.
The plant diet is also good for improving one’s health and resistance to the common American diseases.
Quick Start
http://w888.epizy.com/health/QuickStart.htm
Doc doesn’t mention UC in video, but talks about foods affecting the intestinal tract
https://www.drmcdougall.com/health/education/videos/mcdougalls-moments/intestinal-tract/
Success stories
https://www.drmcdougall.com/health/education/health-science/stars/stars-written/andrew/
https://www.drmcdougall.com/health/education/health-science/stars/stars-written/gabrielle-fennimore/
https://www.drmcdougall.com/health/education/health-science/stars/stars-written/weavers/
Dr McDougall forum (The Lounge forum is particularly good for sharing experiences)
https://www.drmcdougall.com/forums/search.php?keywords=ulcerative+colitis
I switched to the plant diet not for UC, but to lower cholesterol — so quickly that I was off Lipitor in 10 weeks, for good. Being 100% clear of UC signs of scarring and polyps was an unexpected benefit!