Artificial sweeteners like Splenda and Equal may have negative effects on intestinal bacteria. How do sugar alcohols like erythritol affect gut flora?
A. You're not the only one to wonder! Many new sugar-free sweeteners are a blend of stevia and erythritol, which is a sugar alcohol. Many listeners wrote to ask whether the effects of erythritol are known. Although stevia may support beneficial bacteria, it appears that erythritol promotes neither "good" nor "bad" intestinal bacteria.
See also: What is Gut Microbiota?
Researchers found that erythritol is resistant to fermentation by a range of microbiota from human guts. This is why erythritol is less likely to cause gas or bloating than other sugar alcohols. But it also suggests that erythritol wouldn't alter the makeup of your intestinal flora the way saccharine, sucralose, or aspartame might.
Despite this encouraging fact, I'm sticking with my previous advice to consume all sweeteners (caloric and non-caloric, natural and artificial) with restraint!
Arrigoni E, Brouns F, Amadò R. Human gut microbiota does not ferment erythritol. Br J Nutr. 2005 Nov;94(5):643-6.