There may be an Iodine connection here. I think that plays a part in IBD.
Soya and cabbage family are both goitrogens so may be you overdid them.
THe solution is to limit the goitrogens and take a form of Iodine as a supplement.
Lugols is what I use but over 8 drops I reduce it to Iodide with vitamin C to avoid irritation,also selenium is needed as selenomethionine and some magnesium
Larger doses of potassium Iodide as SSKI may have more benefit over time.
I have kept my UC in remission since last april and I believe Iodine is why I succeeded when I failed before to do so for so long