Are Carboxymethylcellulose, Polysorbate 80, and Other Emulsifiers Safe? 

Emulsifiers are the most widely used food additives. What are they doing to our gut microbiome?

When grocery shopping these days, unless you’re sticking to the produce aisle, “it is nearly impossible to avoid processed foods, particularly in the consumption of a typical Western diet,” which is characterized by insufficient plant foods, too much meat, dairy, and eggs, and a lot of processed junk, “along with increased exposure to additives due to their use in processed foods.”

The artificial sweetener sucralose, for example, which is sold as Splenda, “irrefutably disrupts the gut microbiome at doses relevant to human use” and “induces glucose intolerance.” In other words, it can make our blood sugars worse instead of better. It’s relatively easy to avoid artificial sweeteners, but “it may be much more difficult to avoid ingestion of emulsifiers…because they are commonly added to a wide variety of foods within the modern Western diet.” In fact, “emulsifiers are the most widely used additives,” and “most processed foods contain one or more emulsifiers that allow such foods to maintain desired textures and avoid separation into distinct parts (e.g, oil and water layers).” We now consume emulsifiers by the megaton every year, thanks to a multibillion-dollar industry, as you can see below and at 1:03 in my video Are Emulsifiers Like Carboxymethylcellulose and Polysorbate 80 Safe?.

Emulsifiers are commonly found in fatty dressings, breads and other baked goods, mayonnaise and other fatty spreads, candy, and beverages. “Like all authorized food additives, emulsifiers have been evaluated by risk assessors, who consider them safe. However, there are growing concerns among scientists about their possible harmful effects on our intestinal barriers and microbiota,” in terms of causing a leaky gut. As well, they could possibly “increase the absorption of several environmental toxins, including endocrine disruptors and carcinogens” present in the food.

We know that the consumption of ultra-processed foods may contribute to weight gain. Healthier, longer-lived populations not only have low meat intake and high plant intake, but they also eat minimally processed foods and “have far less chronic diseases, obesity rates, and live longer disease-free.” Based on a number of preclinical studies, it may be that the emulsifiers found in processed foods are playing a role, but who cares if “emulsifiers make rats gain weight”? When we read that “emulsifiers can cause striking changes in the microbiota,” they aren’t talking about the microbiota of humans.

Often, mice are used to study the impact on the microbiome, but “only a few percent of the bacterial genes are shared between mice and humans.” Even the gut flora of different strains of mice can be considerably different from each other, so if we can’t even extrapolate from one type of mouse to another, how are we supposed to translate results from mice to humans? “Remarkably, there has been little study of the potential harmful effects of ingested…emulsifiers in humans.”

Take lecithin, for example, which is “perhaps best known as a key component of egg yolks.” Lecithin was found to be worse than polysorbate 80 in terms of allowing bacteria to leak through the gut wall into the bloodstream. However, it’s yet to be determined whether lecithin consumption in humans causes the same problem. “There is certainly a paucity in the data of human trials with the effects of emulsifiers in processed foods,” but we at least have data on human tissue, cells, and gut flora.

A study was titled: “Dietary emulsifiers directly alter the human microbiota composition and gene expression ex vivo potentiating intestinal inflammation.” Ex vivo means outside the body. Researchers inoculated an artificial gut with fresh human feces until a stable culture was established, then added carboxymethylcellulose (CMC) or polysorbate 80 (P80), resulting in boosts in proinflammatory potential starting within one day with the carboxymethylcellulose and within the first week with polysorbate 80, as you can see below and at 3:39 in my video.

“This approach revealed that both P80 and CMC acted directly upon human microbiota to increase its proinflammatory potential…” When researchers then tested the effect of these emulsifiers on the protective mucus layer in petri dish cultures of human gut lining cells, they found that they can partially disrupt the protective layer. As you can see below and at 4:00 in my video, the green staining is the mucus. Both emulsifiers cut down the levels.

However, this study and the last both used emulsifier concentrations that were far in excess of what people might typically get day-to-day. 

“Translocation of Crohn’s disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers” is probably the study that raised the greatest potential concern. The researchers surgically obtained cells, as well as actual intestinal wall tissue, and found that polysorbate 80 could double the invasion of E. coli through the intestinal lining tissue, as shown here and at 4:27 in my video.

In contrast, adding fiber—in this case, fiber from plantains—could seal up the gut wall tissue twice as tightly, as seen below and at 4:33.