I think it varies for the person and how they might react to it.  I have heard + and - from specialists on this one.

I have been having a lot of gi issues, but my gi exam showed very little mast cells in the gi and stable tryptase... still, what was the cause?  In my case, may be a little IBD that runs in the family and acts up when I stress out.  My masto meds just were NOT making a dent in it, so I looked a little deeper.

I have found, thus far, that a little bit of Kefir everyday seems to help.  My gi specialist recommended this as a little more "natural" approach if some of the gi issues might be from overgrowth of "bad" bacteria.   I got some from Trader Joes.  It seems to make everything calm down a bit for me, as it adds in more of the gi friendly bacteria that helps the microflora be more normal.... that's the theory anyway.  I don't think there are many studies on this yet.  Given all the antihistamines we usually take, that would tend to dehydrate us and that might factor into motility problems.

I think you just have to try it out and see how it goes.  Fermented things do seem to bug us, so of course, you have to be cautious.  For me, I found it seemed to help a bit so far.

If you find a good solution for this, let me know.  I am really struggling with this and trying the Kefir a little more frequently now too.  Will let you know how it goes.  I am a firm believer in trying the most natural approaches possible to bring the body into balance.  I think maintaining a good physiological balance is very important for our condition.  You have to think like that "Baby Bear" in the Goldilocks story..... got to have everything be "JUST RIGHT!"

I made homemade kefir and kombucha from kefir grains and kombucha mushrooms for over a year.   I LOVED it !   But I found that I was becoming increasingly reactive while drinking them.   In the end, I think it made my mast cell condition worse.   I had to quit them altogether.

As I said, I LOVED these drinks.  So maybe I drank too much of them.
I would recommend caution, and paying attention to how you are doing over time.

I wish I could drink kefir, as there is a nutraceutical kefir product called MAF314 which is supposed to ...um... recouple the vitamin D transporting molecule, which is theoretically split by nagalase ... and the nagalase is ...um... induced by or contained in some viral envelope proteins (I hope I got that right).   Anyway, the end result is a subtle immune deficiency, which is "supposedly" corrected by MAF314 (Macrophage Activating Factor).   MAF is sold as an injectible in Europe btw to treat HIV and cancer.

Germane to Masto ?   I don't know.

Todd in Tenn.