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Do Emulsifiers Affect the Gut Microbiome?

Posted: 2025-04-17

 

What’s happening?

The PEN team was made aware of recent interest in the role of emulsifiers and gut microbiome and health. Dietary emulsifiers help to combine or stabilize substances that usually don’t stay together when mixed (1). They affect a food’s appearance, texture and shelf-life and are commonly found in processed and ultra-processed foods such as margarine, mayonnaise and salad dressings, sauces, nut butters, chocolate products, milk and dairy, including ice cream products and commercially made baked goods (1-3). Emulsifiers can be natural (e.g. lecithin, guar gum and pectin) or synthetic (e.g. carboxymethylcellulose (CMC) and polysorbate 80 (P80)) (1).

The addition of emulsifiers to food products is legislated in Australia (Food Standards Australia New Zealand (FRANZ), Canada (Health Canada) and the European Union (European Food Safety Authority (EFSA)). In general, food additives that are permitted for use in Canada are similar to those allowed in other countries (including Australia and New Zealand, Europe and the United States) for uses accepted internationally in the Codex General Standard for Food Additives (Codex Alimentarius) (4).

Challenges in reviewing the literature related to emulsifiers is that their definition and food labelling requirements vary across the globe (3,5). As an example, the Codex Alimentarius lists more than 260 emulsifier types while the U.K. Food Standard Agency lists 63 (3,5). Emulsifiers are often grouped under the main category of food additives and can be combined with stabilizers, gelling agents and thickeners (1,2). The Food and Agriculture Organization (FAO) and World Health Organization (WHO) are proposing an international numbering system to name food additives, including emulsifiers, to help with clarification (3).

Evidence review

While food additives have existed for years, concerns with their use arose with the increased consumption of processed and ultra-processed foods. Some in vitro (often via a simulated human gut model) and animal studies identified that some emulsifiers such as CMC, P80, agar agar, carrageenan and gums, may affect gut bacteria diversity and impair the gut lining barrier (3,5-9). However, studies on the impact of dietary emulsifiers on the microbiome in humans are limited. One intervention study and a couple of indirect observational studies are highlighted below:

• A randomized, double-blind feeding study was conducted on healthy adults who consumed an emulsifier-free diet (n=9) or the same diet enriched with 15 g of CMC per day (n=7) for 14 days [10]. After analyzing blood, plasma, urine, and fecal samples, it was found that the participants with the added CMC diet had abdominal discomfort, reduced microbiota diversity, and altered fecal metabolome (reduced short-chain fatty acids and free amino acids).

• Participants (n>92,000) from the French NutriNet-Santé prospective cohort who completed at least three repeated 24-hour dietary records were observed for disease occurrence over about 7 years (11-13). Comparing higher to lower consumers of various food additive emulsifiers, small positive associations were observed for cancer (overall cancer, breast and prostate) (11), cardiovascular disease (12) and type 2 diabetes (13). The authors suggest that disruptions in the gut microbiota and increased gut inflammation could be a contributing factor to systemic low grade inflammation that may impact other organs (11).  

Further epidemiological and experimental research is needed to confirm these results.

The bottom line

While some commonly used emulsifiers may alter the gut microbiota and potentially promote intestinal and metabolic inflammation, more clinical trials are needed to understand specific emulsifiers and their effects on microbiota and health outcomes in humans (good and bad effects), including the cumulative effect of consuming a variety of emulsifiers together and chronic exposure (3,5).

Processed and pre-packaged foods that contain emulsifiers are often also higher in fat, sugar and/or sodium (2). For the general public, focusing on fresh and whole foods with as little processing as possible, encouraging a nutritious and varied diet based on country specific dietary guidelines, reading ingredient lists on food products to avoid added emulsifiers and cooking/baking at home are ways to help reduce emulsifier intake (14). For individuals at high risk of inflammatory bowel disease (IBD), PEN evidence cites the 2023 ESPEN guidelines, which recommend a diet that excludes ultra-processed foods and CMC to help prevent IBD (15). This Grade C evidence suggests that more research is needed to support this recommendation.  

See Additional Content:

• PQ: Are there dietary factors that increase or decrease the risk of developing inflammatory bowel disease (IBD)?

• Microbiota Background

References

1. EUFIC. What are emulsifiers and what are common examples used in food? 2022 oct. Available from: https://www.eufic.org/en/whats-in-food/article/what-are-emulsifiers-and-what-are-common-examples-used-in-food

2. Sandall A, Smith L, Svensen E, Whelan K. Emulsifiers in ultra-processed foods in the UK food supply. Public Health Nutr. 2023 Nov;26(11):2256-2270. doi: 10.1017/S1368980023002021. Epub 2023 Sep 21. PMID: 37732384; PMCID: PMC10641632. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/37732384/

3. Cox S, Sandall A, Smith L, Rossi M, Whelan K. Food additive emulsifiers: a review of their role in foods, legislation and classifications, presence in food supply, dietary exposure, and safety assessment. Nutr Rev. 2021 May 12;79(6):726-741. doi: 10.1093/nutrit/nuaa038. PMID: 32626902. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/32626902/

4. Health Canada. Food additive overview. 2025-03-07. Available from: https://www.canada.ca/en/health-canada/services/food-nutrition/food-safety/food-additives.htm

5. De Siena M, Raoul P, Costantini L, Scarpellini E, Cintoni M, Gasbarrini A, Rinninella E, Mele MC. Food Emulsifiers and Metabolic Syndrome: The Role of the Gut Microbiota. Foods. 2022 Jul 25;11(15):2205. doi: 10.3390/foods11152205. PMID: 35892789; PMCID: PMC9331555. Abstract available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9331555/ 

6. Naimi S, Viennois E, Gewirtz AT, Chassaing B. Direct impact of commonly used dietary emulsifiers on human gut microbiota. Microbiome. 2021 Mar 22;9(1):66. doi: 10.1186/s40168-020-00996-6. PMID: 33752754; PMCID: PMC7986288. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/33752754/

7. Miclotte L., De Paepe K., Rymenans L., Callewaert C., Raes J., Rajkovic A., Van Camp J., Van de Wiele T. Dietary emulsifiers alter composition and activity of the human gut microbiota in vitro, irrespective of chemical or natural emulsifier origin. Front. Microbiol. 2020;11:577474. doi: 10.3389/fmicb.2020.577474. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/33250870/ 

8. Chassaing B, Koren O, Goodrich JK, et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature 2015;519:92–96. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/25731162/

9. Chassaing B, Van de Wiele T, De Bodt J, et al. Dietary emulsifiers directly alter human microbiota composition and gene expression ex vivo potentiating intestinal inflammation. Gut 2017;66:1414–1427. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/28325746/

10. Chassaing B, Compher C, Bonhomme B, Liu Q, Tian Y, Walters W, Nessel L, Delaroque C, Hao F, Gershuni V, Chau L, Ni J, Bewtra M, Albenberg L, Bretin A, McKeever L, Ley RE, Patterson AD, Wu GD, Gewirtz AT, Lewis JD. Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome. Gastroenterology. 2022 Mar;162(3):743-756. doi: 10.1053/j.gastro.2021.11.006. Epub 2021 Nov 11. PMID: 34774538; PMCID: PMC9639366. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/34774538/

11. Sellem L, Srour B, Javaux G, Chazelas E, Chassaing B, Viennois E, Debras C, Druesne-Pecollo N, Esseddik Y, Szabo de Edelenyi F, Arnault N, Agaësse C, De Sa A, Lutchia R, Huybrechts I, Scalbert A, Pierre F, Coumoul X, Julia C, Kesse-Guyot E, Allès B, Galan P, Hercberg S, Deschasaux-Tanguy M, Touvier M. Food additive emulsifiers and cancer risk: Results from the French prospective NutriNet-Santé cohort. PLoS Med. 2024 Feb 13;21(2):e1004338. doi: 10.1371/journal.pmed.1004338. PMID: 38349899; PMCID: PMC10863884. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38349899/  

12. Sellem L, Srour B, Javaux G, Chazelas E, Chassaing B, Viennois E, Debras C, Salamé C, Druesne-Pecollo N, Esseddik Y, de Edelenyi FS, Agaësse C, De Sa A, Lutchia R, Louveau E, Huybrechts I, Pierre F, Coumoul X, Fezeu LK, Julia C, Kesse-Guyot E, Allès B, Galan P, Hercberg S, Deschasaux-Tanguy M, Touvier M. Food additive emulsifiers and risk of cardiovascular disease in the NutriNet-Santé cohort: prospective cohort study. BMJ. 2023 Sep 6;382:e076058. doi: 10.1136/bmj-2023-076058. PMID: 37673430; PMCID: PMC10480690. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/37673430/ 

13. Salame C, Javaux G, Sellem L, Viennois E, de Edelenyi FS, Agaësse C, De Sa A, Huybrechts I, Pierre F, Coumoul X, Julia C, Kesse-Guyot E, Allès B, Fezeu LK, Hercberg S, Deschasaux-Tanguy M, Cosson E, Tatulashvili S, Chassaing B, Srour B, Touvier M. Food additive emulsifiers and the risk of type 2 diabetes: analysis of data from the NutriNet-Santé prospective cohort study. Lancet Diabetes Endocrinol. 2024 May;12(5):339-349. doi: 10.1016/S2213-8587(24)00086-X. PMID: 38663950. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38663950/ 

14. FAO. Ultra-processed foods, diet quality, and health using the NOVA classification system. 2019. Available from: https://openknowledge.fao.org/server/api/core/bitstreams/5277b379-0acb-4d97-a6a3-602774104629/content

15. Dietitians of Canada.  Are there dietary factors that increase or decrease the risk of developing inflammatory bowel disease (IBD)? In PEN: Practice-based Evidence in Nutrition. 2024-11-19. Available from: https://www.pennutrition.com/KnowledgePathway.aspx?kpid=5877&pqcatid=145&pqid=5835