Thanks, good advice. I will do some longer water fasts.
AFAIK regarding fermented glutamine, the fermentation has to do with the manufacturing method from beets in contrast to the more traditional chemical extraction of l-glut from bird feathers and
human hair. Ideally, in either case the final amino is highly purified, but it's claimed that fewer and/or safer solvents are utilized during the beet fermentation process. IBS is reported to be helped by l-glutamine supplementation in some instances:
Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome
It's interesting that glutamine acts as a precursor to citrulline, which in turn is a precursor to arginine. Probably best to stick to whole food sources, but l-glut is commonly recommended by experts for leaky gut.