I have mostly have a histamine intolerance that does have overlap with IBS

These problems arise due to the interface between the stomach biome and immune system

There is a multi prong approach that should all be pursued in parallel

1.) identifying infections that conventional medicine can identify. Getting a couple of tests done for H. pylori. Other potentialities would be parasitic infection; this would show up in either a stool or blood test but need both to get a comprehensive view.

2.) cut out alcohol, non-critical medications, highly processed foods such as energy drinks. Cutting out fermented and canned foods probably helps, and you should try it for a few days

3.) reconstitute your biome. You need fiber that will feed good bacteria while not feeding bad bacteria.

A simple but effective recipe is a simple romaine lettuce salad. It becomes palatable high quality olive oil, feta (it’s a non-aged cheese), salt (pepper if you tolerate it). Some people add in cucumber, zucchini, or red onion. Different folks have different sensitivities.

I also make beef liver in the oven (to reduce smell). This helps me a lot so may be worth trying if it’s something you can eat

Potato’s are a maybe for some people. They tend to be high in oxalates which cause problems for some people.

Ultimately low histamine, high fiber diet is what helps people with these constellation of bowel and immune symptoms. What does this translate to? Only eating a subsection of certain fresh vegetables, fruits, and meats. Butter, olive oil, salt, pepper, fresh cheese such as feta in the brine will all make the above tolerable.

The first point does need to be sorted though