While I have not read the actual paper, according to the article the participants in the group were very carefully tested against different levels of gluten in

While I have not read the actual paper, according to the article the participants in the group were very carefully tested against different levels of gluten in their food, and they reported _negative effects_ for each level of gluten contents. Note that the food was _also_ controlled for FODMAPs, again, showing effects even without any known effector. So there does indeed seem to be an gastrointestinal effect of eating these foods, but, again, according to the article, it seems to be psychological in nature. The conclusion seems valid: gluten content doesn't make a difference, and negative effects are reported even in the absence of gluten and FODMAPs. At least for the group of participants, neither gluten nor other FODMAPs seem relevant. Until the affected people know better what it is that causes harm to them, they can (and probably should) ignore gluten content.