I also believe there is a microbiome component to POIS. When I was very young I got a lot of strep throat so I was put on antibiotic every other week. I can remember having accidents when I was little up until maybe 12 years old because I could barely hold back pooping. Looking back I think the antibiotics were the cause. So it is quit possible there is a link since I had mild POIS from my 1st orgasm on. To this day I have major gastrointestinal problems and part of my POIS numbs my lower abdominals and then after 24 hours they get very inflamed and I could have the worst level 10 pain depending on what I eat. I learned that if I avoid dairy that helps some. Also less junk type of food help. So no fried foods, candy, soda, ect? all things I love.
Regarding Mastic Gum I have been using it for over a decade and I have used every form of it, chewing gum, mastic tears, tea, tooth paste, oil, baking with it and and capsules. I have seen no improvement of POIS symptoms with it. It?s more of a stomach and teeth medicine than a colon and intestinal medicine.
Most of the the digestive supplements I have tested over the years and there are so many you would not believe, have helped my gut but with no effect on my POIS.
The last 5 years I have focused on my microbiome and I suggest everyone get microbiome testing, it is the future of medicine. The Microbiome is extremely resilient, antibiotics can whip out healthy and harmful bacteria but they usually come back depending. But probiotics also only has a temporary change for it. The trick is adding on a consistent basis as much different fibers as possible. It?s not about quantity but variety. Also natural ferments, like sauerkraut, Kefir, Kombuchas, Natto, ect?
