I'm not sure what everyone's experience is, but for me, MCAS symptoms (chiefly brain fog, but sometime gut discomfort or other things) arise pretty quickly after eating fermented foods. If you look up a low-histamine diet and follow it for a couple of days, and then re-introduce some super-fermented things, then you might be able to tell pretty easily if those things are bothering you.
I find that I can handle small amounts of histamine better when MCAS is more controlled in general, like with plenty of quercetin and turmeric and histaminum (homeopathic). Some also get good results with antihistamine drugs and freeze-dried stinging nettles supplements. If you find that you need some high-histamine things in your diet, then you can control your histamine responses somewhat through these supplements.
That said, some people react more to other types of histamines, like the ones their bodies are producing due to allergen exposure (pollen, dust mites, dander) or environmental irritants (mold, chemicals) and therefore for those people diet might not make as much of a difference in histamine reactions.
JB's point about
SIBO makes sense, too. A die-off reaction from a pathogenic bacterial overgrowth could make you feel crummy for a week or two. Have you had any testing done for SIBO?
Neil Nathan's book Toxic is a good way to explore some possibilities for people who seem to react to a lot of things, or who have overlapping conditions with Lyme that can be difficult to untangle.
You're not wrong that your gut may need probiotic foods and that healing your gut is so important! There are low-histamine strains of probiotics you could supplement, if you do determine MCAS is an issue for you (it might not be!). Here'a list: https://wholenewmom.com/health-concerns/low-histamine-probiotics/ And so many other things are good for your gut and fine for MCAS - low-lectin diet, bone broth, digestive enzymes, omega 3s, licorice and marshmallow (the herbs, not the candies
![smile](/community/emoticons/smile.gif)
), etc. You definitely can heal leaky gut and other gut issues without fermented foods IF it is necessary.