Emulsifiers are common food ingredients that are used to enhance the flavor, texture, stability, and shelf-life of processed foods. Food emulsifiers range from common products like mustard and canola oil, to food additives such as lecithins, polysorbates, and carrageenan.
In recent years, researchers have published articles that call into question the potential impacts of dietary emulsifiers on gut inflammation and chronic disease. In response to these claims, the International Food Additives Council (IFAC) points to the overwhelming scientific evidence that supports the safety of these ingredients, which is summarized in a 2018 literature review by Vo et al., titled “Dietary Exposures to Common Emulsiﬁers and Their Impact on the Gut Microbiota: Is There a Cause for Concern?”.
For this review, the authors reviewed all published literature on dietary emulsifiers and human impacts. Despite claims to the contrary, Vo et al., found there is limited evidence indicating adverse effects of emulsifiers on the microbiome. The authors suggest that an established and agreed upon range of different microorganisms within the microbiome would help to provide a reference for future studies in the interpretation and clinical relevance of changes observed in response to various dietary components and ingredients. Given this, the researchers found that consumption of foods containing dietary emulsifiers do not pose any safety concerns and that their history of safe use is not brought into question by the existing scientific literature.
Studies linking animal models to human health outcomes have many limitations. There continues to be limited evidence indicating adverse effects of emulsifiers on the microbiome. More about what we do know can be found here.
Recent publications that have questioned the safety of dietary emulsifiers:
In October 2020, the publication “Dietary Emulsifiers Directly Impact Adherent-Invasive E. coli Gene Expression to Drive Chronic Intestinal Inflammation” by Viennois et al., suggested dietary emulsifiers disturb gut microbiota and promote chronic inflammation. In this study, mice were colonized with Crohn’s-disease-associated adherent-invasive E. coli (AIEC) and administered common emulsifiers carboxymethyl cellulose (CMC) or polysorbate-80 (P80). The authors conclude that dietary emulsifiers promote virulence and encroachment of pathobionts, providing a means by which these compounds may drive inflammation in hosts carrying such bacteria.
Upon further review, the authors note that the underlying prevalence of AIEC (a strain of E. coli known to be a factor in the development of Crohn’s Disease) in humans is not well understood, which calls into question the relevance of these findings to humans. Additionally, while the authors suggest that AIEC interacts with CMC, causing gut inflammation, they also note that the CMC levels used in this study are much higher than those consumed through the diet and incorrectly state that their would be similar in humans, who could have similar exposure over a long period of time compared to an acute exposure like the mice in this study.
Another study, published in November 2020 and titled, “Is sodium carboxymethyl cellulose (CMC) really completely innocent? It may be triggering obesity”, concluded the dietary emulsifier CMC can cause changes in the expression of some genes associated with obesity. Authors Baran et al., provided CMC through the food of zebrafish embryos by the microinjection method at different concentrations. The authors concluded that CMC does not cause a toxic effect in zebrafish embryos, but assert that their findings show that CMC can lead to important effects on lipid metabolism by causing changes in the expression of some genes associated with obesity.
IFAC notes that this study, having been conducted in zebrafish, is not relevant to human exposure and should not alter our use or understanding of the benefits of various emulsifiers that are used to improve food product texture, stability, and shelf life.