Are emulsifiers bad for you?
Emulsifiers keep oil and water mixed, the way egg yolk holds mayonnaise together. The evidence that they harm people is early. In an 11-day trial in 16 adults, the emulsifier carboxymethylcellulose (CMC) changed gut bacteria. In 95,442 French adults, eating more of some emulsifiers went with slightly more heart disease. Neither study settles it.
Emulsifiers have become the villain of the additive world, helped by their long names. Others point out that egg yolk is an emulsifier too. In people, there’s one small trial and one big observational study, and they lean the same way without proving much.
We wouldn’t avoid emulsifiers one by one. We’d use them as one more reason to pick the plainer staple, since the loaf, the chocolate bar and the dressing with no emulsifier also have nothing else on the label a kitchen wouldn’t keep.
An emulsifier works like dish soap on a greasy pan. One end of the molecule grabs fat and the other grabs water, so the two stop separating.
The trial in people
Researchers fed 16 healthy adults a diet with no emulsifiers for 11 days. Seven of them also got 15 g a day of CMC, baked into brownies and blended into sorbet, and nobody knew who had it.
| Measure | What CMC did |
|---|---|
| Stomach discomfort after meals | Modestly more |
| Gut bacteria | Less diverse, though two of the diversity scores weren’t significant |
| Short-chain fatty acids (made by gut bacteria from fiber) | Lower |
| Bacteria moving into the gut’s inner mucus layer | 2 of 7 people on CMC, 0 of 9 without, not statistically significant |
The authors say it was short and couldn’t tell whether some people react and others don’t.
The big study
Sellem and colleagues followed 95,442 French adults for a median of 7.4 years and tracked which additives they ate. Higher intake of celluloses, including CMC, went with more heart disease, about 5% more for each step up in intake (one standard deviation). Two kinds of esters of mono- and diglycerides (E472b and E472c) went with more too. The authors wrote that “owing to the observational nature of our study, we were unable to confirm that emulsifiers are causally related” to heart disease.
Where they show up
| Food | Labels with an emulsifier | The common one |
|---|---|---|
| Protein bars | 60 of 97 | soy or sunflower lecithin |
| Dark chocolate | 51 of 97 | soy lecithin |
| Packaged sliced bread | 49 of 94 | soy lecithin, mono- and diglycerides |
From US labels in Open Food Facts, checked with this site’s label checker on November 14, 2026. NOVA counts every emulsifier as a marker of ultra-processed food.
The bigger effects in the trials of ultra-processed food come from eating more of it. On the NIH ward, people ate 508 more calories a day on the ultra-processed menu, and the trial wasn’t designed to say which part of the food caused it.
What we’d do
- Pick the plain version of the staples you eat most: bread, chocolate, dressing.
- Skip the label hunt for every lecithin. Swapping staples takes most of it out.
- See which additives have evidence in people in the additives guide.
5 sources
- Chassaing et al., Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome, Gastroenterology, 2022pmc.ncbi.nlm.nih.gov
- Sellem et al., Food additive emulsifiers and risk of cardiovascular disease in the NutriNet-Santé cohort: prospective cohort study, BMJ, 2023pmc.ncbi.nlm.nih.gov
- Monteiro et al., Ultra-processed foods: what they are and how to identify them, Public Health Nutrition, 2019pmc.ncbi.nlm.nih.gov
- Open Food Facts, US products in the categories sliced breads (94 ingredient lists), dark chocolates (97) and protein bars (97), checked with this site's label checker on November 14, 2026us.openfoodfacts.org
- Hall et al., Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake, Cell Metabolism, 2019pmc.ncbi.nlm.nih.gov
