There is a very good chance that some are harmful in that they may be partially responsible for the increase in allergies. metabolic syndrome, and some immune related disorders we've seen over the last century.

The reason is, that emulsifier thin the mucus of the intestines, which brings bacteria and food proteins closer to the cells of the intestine.

 

Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome

 

Here we report that, in mice, relatively low concentrations of two commonly used emulsifiers, namely carboxymethylcellulose and polysorbate-80, induced low-grade inflammation and obesity/metabolic syndrome in wild-type hosts and promoted robust colitis in mice predisposed to this disorder. Emulsifier-induced metabolic syndrome was associated with microbiota encroachment, altered species composition and increased pro-inflammatory potential.

 

Other research has shown that a combination of dietary fat + natural emulsifier increases aborption of allergenic proteins into the blood stream,

 

Intact Gly m Bd 30K and its fragments that were < 20 kDa survived digestion and were absorbed into the blood. We propose that absorption was enhanced by fat carrier-mediated transport.