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October 18th, 2021

From the Food and Drug Administration: There are thousands of ingredients used to make foods. The Food and Drug Administration (FDA) maintains a list of over 3000 ingredients in its data base "Everything Added to Food in the United States", many of which we use at home every day (e.g., sugar, baking soda, salt, vanilla, yeast, spices and colors). FDA Let us look at emulsifiers.


Definition - molecules or chemicals that help maintain a food's even mixture of two or more non mixable foods such as oil and water

Emulsifier scientific definition - Food emulsifiers are created by alcoholysis or direct esterification of edible fatty acids taken from animal or vegetable sources with polyols(i.e., glycerol, propylene glycol and sorbitol). Further processing by reaction with ethylene oxide or esterification with organic acids produces a wide range of emulsifiers with differing properties. The most commonly used food emulsifiers include MDGs, stearoyl lactylates, sorbitan esters, polyglycerol esters, sucrose esters, and lecithin.

Emulsifiers are a common food additive by the United States food industry with the designed purpose to increase the smooth texture and palatability of processed foods . They have been in use for a long time and come in natural and synthetic versions. In one study, it was found that 58% of the calories consumed by the 9317 person study population consumed ultraprocessed foods which include many emulsifiers. (Martines-Steele et. al. 2020) That number mirrors on the low end, what I see in clinic. Processed foods tend to make up the majority of the foods that my patients consume, sadly.

When we think of processed foods and emulsifiers, think of peanut butter as an example. Natural peanut butter separates and has an oil layer on top whereas the modern commercial brands never separate. The emulsifiers hold the peanut butter in place. Take Jif for example, it contains hydrogenated oils as an emulsifier as these oils maintain consistency at room temperature. However, these oils are well known to be unhealthy in volume. High volumes of free fatty acids can drive the mechanisms involved in insulin resistance whereby diacylglycerol elevations drive muscle based glucose transporter, GLUT4, translocation dysfunction. This is inherently negative to long term health.

Typically used emulsifiers are lecithins (E322), mono- and diglycerides of fatty acids (E471), lactic acid esters of mono- and diglycerides of fatty acids (E472b) and polyglycerol esters of fatty acids (E475). Emulsifiers provide stability and improve the spreadability of various spreads, including peanut butter.(Link)

As always, the advancement of food technology comes with a benefit and potentially a cost. The benefit is clear, mouth feel and palatability which encourages sales and consumption which is great for a corporate bottom line and human taste preferences. The cost is unstudied in humans to a known degree, thus it is considered by the FDA as generally recognized as safe. However, we have animal translational models that are of concern.

In a Nature study by Dr. Chassaing and colleagues we see a data set raising a legitimate concern regarding synthetic emulsifiers. Let us look at the title, Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Reading the abstract will help us see the mechanism that could underline a human risk: "The intestinal tract is inhabited by a large and diverse community of microbes collectively referred to as the gut microbiota. While the gut microbiota provides important benefits to its host, especially in metabolism and immune development, disturbance of the microbiota–host relationship is associated with numerous chronic inflammatory diseases, including inflammatory bowel disease and the group of obesity-associated diseases collectively referred to as metabolic syndrome. A primary means by which the intestine is protected from its microbiota is via multi-layered mucus structures that cover the intestinal surface, thereby allowing the vast majority of gut bacteria to be kept at a safe distance from epithelial cells that line the intestine. Thus, agents that disrupt mucus–bacterial interactions might have the potential to promote diseases associated with gut inflammation. Consequently, it has been hypothesized that emulsifiers, detergent-like molecules that are a ubiquitous component of processed foods and that can increase bacterial translocation across epithelia in vitro, might be promoting the increase in inflammatory bowel disease observed since the mid-twentieth century. 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. Use of germ-free mice and faecal transplants indicated that such changes in microbiota were necessary and sufficient for both low-grade inflammation and metabolic syndrome. These results support the emerging concept that perturbed host–microbiota interactions resulting in low-grade inflammation can promote adiposity and its associated metabolic effects. Moreover, they suggest that the broad use of emulsifying agents might be contributing to an increased societal incidence of obesity/metabolic syndrome and other chronic inflammatory diseases."

Breaking this down: This is an animal model study that gives us a mechanistic risk in mammals that could be driving part of the human issues with rising rates of metabolic syndrome and inflammatory bowel diseases. The loss of the protective mucous layer is a critical really step in intestinal cellular damage and then progression to a leaky gut and food immune interactions that promote intestinal inflammation and human disease.

To me, this is only a piece of the web of risk and disease. The fatty acids and the chemical emulsifiers are a part of the complex process of intestinal immune dysregulation that leads to a myriad of inflammatory disease states including poor responses to viral infections like covid as Dr. Fasano's work has associated. This study and the others listed below are not proof of cause and effect in humans so much as they are mechanisms of possible risk if we consume newer technologically altered processed foods.

Let us now look at the limited human data. In a study from Frontiers in Microbiology by Dr. Elman and colleagues, we see 20 human subjects microbiomes tested against the use of emulsifiers. They looked at the effects of five different emulsifiers [glycerol monoacetate, glycerol monostearate, glycerol monooleate, propylene glycol monostearate, and sodium stearoyl lactylate (SSL)] on fecal microbiota in vitro. SSL significantly reduced concentrations of butyrate, and increased concentrations of propionate compared to control cultures. The presence of SSL increased lipopolysaccharide, LPS and flagellin in cultured communities, thereby enhancing the proinflammatory potential of SSL-selected bacterial communities. (Elman et. al. 2020) This study is small but shows a strong change in the metabonome and quality of microbes present of the human's gut after exposure to these emulsifiers. These changes are noted to be associated with increased inflammation in the GI tract. LPS or lipopolysaccharide is a bacterial cell wall by product that is uber stimulating in a negative way to the immune system when chronically exposed and can lead to a state that Patrice Cani calls low level endotoxemia. Essentially, over time you are slowly degrading the mucous lining and exposing the intestinal cells to bacteria and their byproducts which stimulates local inflammation leading to many different immune mediated disease types including autoimmune and allergic types.

There are big projects underway to answer this question: "Emerging in vitro and animal evidence suggests that food additives such as emulsifiers may contribute to gut and metabolic disease development through alterations to the gut microbiota, intestinal mucus layer, increased bacterial translocation and associated inflammatory response. The MECNUT Emulsifier project aims to further explore the mechanistic basis for these relationships across a wide range of permitted dietary emulsifiers and detergents in vitro. As part of this work package, the FADiets study aims to determine the impact of soy lecithin on gut and metabolic health in vivo using a controlled dietary intervention. This growing area of nutritional science may lead to innovative knowledge, which could pave new ways of addressing gut and metabolic health via implementing dietary guidelines directed at food additives." (Halmos et. al. 2019)

You as the consumer must choose a path forward based on the data that exists and not just blind faith in regulatory agencies that may or may not be doing their job. In an upcoming podcast, I speak with Dr. Lindsey Albenberg regarding gut immune health and she discusses this topic and many others that are worthy off your time. Stay tuned.

Eat all natural whenever possible,

Dr. M



Martinez-Steele BMJ
Chassaing Nature
Cani Trends in Endocr and Metabol
Elman Frontiers in Microbiology
McClements Adv Colloid Interface Science - this article looks at natural alternatives to all of the synthetic concerning varieties
Kinyanjui Encyclopedia of Food Sciences and Nutrition
Partridge Nutrition Bulletin
Halmos Aliment Pharm Therapy