In two weeks we are doing a 'double balloon enteroscopy' - put a scope through the entire small intestine. Hopefully that will prove more definitive. There are other tests before that - very involved and various preparation procedures. It is a bit tiring and requires all of us to work together to not miss or confuse anything.
Another possibility is a gastro neuroendocrine tumor although there are only markers so far, nothing definite. The balloon procedure should clarify that possibility. My time is almost fully involved with details but I have been trying to get this done for years and with my last two emergency hospital visits I changed GI Drs. So finally I have a team to face a challenge that has pressed me harder and harder for at least 25 years.
I’m not very knowledgeable about the gut biome or naturopathy, but I’ve heard from friends with chronic and unexplained diarrhea that taking nutritional yeast can help. I have a friend out in the boonies, who doesn’t have access to reliable internet or health food stores, who makes her own bread or pizza dough and eats 4 nickel-sized balls of raw dough each day. She stores it in a zip-lock bag in the fridge and, just before it begins to sour (about 1 week after making it), she makes bread sticks or pizza with whatever is left. It’s strange, but she said it ends the diarrhea as long as she eats it every day. (Caveat - she says it makes her a little … um, gassy 😳.)
She believes she ruined her gut biome by taking in too much apple cider vinegar for too long a time. Naturopaths, like numberonepal or little jeremiah, may want to weigh in on this idea, but I think it beats taking pharmaceuticals, as long as it works. I don’t think it will hurt you, though you may live in an area where you can easily buy nutritional yeast instead of eating raw pizza dough, which has a bit of the “ewww!” factor.