So,
Short answer - if they don't cause FODMAP symptoms then they aren't an issue, (well, not a FODMAPs issue anyway)
Long answer - FODMAPs......It gets complicated.......
-
"FODMAPs are a collection of short-chain carbohydrates (sugars) that aren’t absorbed properly in the gut, which can trigger symptoms in people with IBS."
-for this very reason many FODMAPs are also prebiotics [1]
If someone is on a low FODMAD diet it is probably because they wish to reduce unpleasant symptoms.
This is done by reducing biological (Microbiomal?) activity.
This is a good short term strategy but in the long term one needs to increase beneficial microbiomal (i like it, i'm gonna use it) activity by feeding the beneficial bacteria
During the FODMAP elimination phase all FODMAPS are kept under the threshold and then we reintroduce different FODMAPS to find your personal threshold [2].
Various FODMAPS are tested and the ones that are tolerated are consumed in appropriate amounts (ie. keeping below the threshold). [3]
If you want to introduce a new food (ie. mushrooms) then follow the same procedure whether you are in in the reintroduction phase or maintenance phase....
To sum it up....
"we all should be eating a diet that is as high in FODMAPs as we can tolerate without getting symptoms" but, eating multiple different FODMAPS (even multiple 'low' FODMAPS) can lead to exceeding our personal tolerance....
so (for example only) maybe 200 grams of mushrooms is ok but 200 grams of mushrooms with garlic might not be..... [4]
[1]
https://fodmapchallenge.com/2017/04/prebiotics-fodmaps-different/
https://alittlebityummy.com/8-low-fodmap-prebiotic-food-sources/
[2] The 3 phases of the low FODMAP diet
https://www.monashfodmap.com/blog/3-phases-low-fodmap-diet/
[3] 10 steps to finding your FODMAP threshold
https://www.helpyourself.com.au/2016/09/find_fodmap-threshold/
[4] FODMAP Stacking Explained: Do Your Food Combinations Trigger Symptoms?
https://www.dietvsdisease.org/fodmap-stacking-explained-food-combinations-trigger-symptoms/