The link below is to a great little piece on asafoetida from BBC Good Food, if you are eager to learn more about this spice. I would advise anyone with coeliac disease to check to ensure it has not been mixed with wheat flour before you buy it. It is a great addition to recipes that are low fodmap. As for the account of it helping with those people who have problems with lentils and beans (foods containing oligo-saccharides) I cannot guarantee that the addition of this spice to dishes will reduce the effects of this fodmap, for those following a low fodmap diet. However if you are following a low fodmap diet and missing onion as a spice it is certainly worth trying.