Artificial sweeteners and the gut.
I'm firmly in the camp that artificial sweeteners should not be a regular feature in someone's diet, and the research has a lot to say for this:
“Our findings reveal that artificial sweeteners do, in fact, disrupt bacterial communication, which can negatively impact digestive balance and are harmful to gut health.” (source)
“Our study is the first to show that some of the sweeteners most commonly found in food and drink — saccharin, sucralose and aspartame — can make normal and ‘healthy’ gut bacteria become pathogenic." (source)
"Here we demonstrate that consumption of commonly used NAS formulations drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota" (source)
But... some are better than others! And as a one-off treat, I myself am impartial to a snack or dessert with artificial sweeteners. For example, when I had IBS, if I made a one-off dessert I would use stevia as a sweetener to avoid refined sugar consumption.
Saccharin, sucralose, and aspartame are at the bottom of the list, and on the "better" side, stevia and xylitol.
Polyols are the last one of interest, as it takes the place of the "P" in FODMAP - which is a group of carbohydrates that are commonly poorly digested. So again, one I would limit.
My final point to share: They're so often hidden in foods! Yogurts are a great example... often you'll see sugar-free "gut healthy" yogurts that are pumped full of artificial sweeteners. Don't fall for it! Opt. for whole natural yogurt and add your own flavorings, like cinnamon, stewed fruit, some honey, etc.