Unresolved IBS Symptoms Seeking Specific Remedies

Hey,

I have had chronic IBS for almost a decade now and haven't quite found anything OTC that reduces my symptoms. In general, my issues are irritability (within 30 mins after eating and or the moment after I defecate) exacerbating my ADHD, also I have low energy, low appetite, causing difficulty gaining weight and fluctuations of constipation, and loose stool (but no diarrhea). I believe most of my symptoms have something to do with fat and bile production because my feces are almost always a light brown/tan coloration with occasional black dots or a conglomerate of tan and brown patches.I feel my irritably is a product of my stool coloration however past and current tests rule out fat malabsorption. In addition, I have issues with high amounts of protein, usually protein bars or powder (isolate or vegan) the day after exercising and may have headaches from gluten products. What's strange is there is no one triggering food and those I do avoid, on occasion, have no ill effect.

I am currently revisiting my issues with a gastroenterologist but it looks like I won't find the answers there. Over the years I have incorporated a quasi-gluten-free whole foods diet limiting processed and packaged foods. I have tried various supplements and specifically for digestive enzymes, in two separate occasions, I have tried Source Natural DE both times having no effect and more recently Enzymedica Digestive Gold with some sort of effect or placebo including what I believe caused mild constipation.

For those that have more nuanced sensitivities similar to what I describe, what supplement or combination of supplements has proven to be effective?

I apologize in advance if my tone feels abrasive, just trying to be direct in the hopes of finding someone who has the same experience and possible remedy.