By slowly introducing the problem food
I have experienced a markedly improved tolerance to Inulin / FOS in garlic and onion by starting with just a tiny tiny bit. If you react noticeably give the body a little time to heal and then halve the amount next time. If you don't react then double it next time - tomorrow perhaps. Keep doing this regularly until the food intolerance improves. Fingers crossed !
There is an interesting video on this method here. And here is another similar video:
10 strains or more, eg: "Soil Based Organism" (SBO) Probiotic blends. My tolerance of dairy *seemed* to improve afterwards. I can't say with 100% certainty, but this is the only obvious cause for my now being able to tolerate milk much much better. When I say tolerate I mean that my Ankylosing Spondylitis symptoms don't worsen in the way they did before. I am however concerned I may still have inflammation that dairy may worsen (eg. Prostate trouble, and Sjorgren's syndrome like symptoms).
Yoghurt & cultured foods
Sugar is well tolerated in Lassi's and Yoghurt drinks. Perhaps we can use this to improve sucrose tolerance, and perhaps also try adding milk, sugar, rice flour and try to build tolerance to them that way.
I find that sucrose is somewhat better tolerated with the vegetable gums often found in sorbet. As with Yoghurt this could perhaps be a useful way to build tolerance.