 Today, when grocery shopping, unless you're sticking to the produce aisle, it's nearly impossible to avoid processed foods, particularly if eating the standard American diet characterized not only by insufficient plant foods and too much meat, dairy, and eggs, but also lots of processed junk, and along with that, an increased exposure to food additives. For example, the artificial sweetener, sucralose sold as Splenda, can disrupt the human gut microbiome and induce glucose intolerance. In other words, it can make your blood sugars worse instead of better. It's relatively easy to avoid artificial sweeteners, but it may be more difficult to avoid ingestion of emulsifiers, because they're commonly added to so many foods. In fact, emulsifiers are the most widely used food additives, and most processed foods contain one or more of them. We now consume emulsifiers by the megaton every year, thanks to a multi-billion dollar industry. You'll commonly find emulsifiers in fatty dressings, fatty spreads, baked goods, mayonnaise, salad dressings, candy, and beverages. Why do we care? Like all authorized food additives, emulsifiers have been evaluated by risk assessors who consider them as safe. However, there are growing concerns among scientists about their potentially harmful effects on our intestinal barrier, in terms of causing a leaky gut, as well as their effects on our microbiome. Moreover, they could possibly increase the absorption of environmental toxins present in the food. We know that the consumption of ultra-processed foods, may be a contributor to weight gain, for example, healthier, longer-lived populations, don't just have low meat intake and high plant intake, but they're eating minimally processed foods. Maybe the emulsifiers found in processed foods could be playing a role based on a number of pre-clinical studies, but who cares if emulsifiers make rats gain weight? When you read emulsifiers can cause striking changes in the microbiota, they're not talking about within human beings. Mice are often used to study diet's impact on the microbiome, but we only share a few percent of bacterial genes in common. Even the gut flora of different mouse strains can be considerably different from each other. So, if you can't even extrapolate from one type of mouse to another, how are you supposed to translate results from mice to human beings? Remarkably, there's been little study of the potential harmful effects of ingested emulsifiers in us. For example, lecithin, perhaps best known as a key component of egg yolks, was found to be worse than polysorbate 80, in terms of allowing bacteria to leak through the gut wall into the bloodstream. But whether lecithin consumption in humans causes the same problem is yet to be determined. There's certainly a paucity of human trials on the effects of emulsifiers and processed foods, but we at least have data on human tissue, cells, and gut flora. Dietary emulsifiers directly alter the composition of the human microbiome, ex vivo, potentiating intestinal inflammation. Ex vivo means outside the body. Researchers inoculated an artificial gut with fresh human feces until they had a nice stable culture going and then added carboxymethyl cellulose, or polysorbate 80, and got a boost in pro-inflammatory potential starting within one day with the carboxymethyl cellulose and within the first week with polysorbate 80. This approach revealed that both emulsifiers acted directly upon human gut bugs to increase their pro-inflammatory potential. If you then test the effect of these emulsifiers on the protective mucus layer in petri dish cultures of human gut lining cells, you'll find that they can partially disrupt the protecting layer. The green standing is the mucus, and both emulsifiers cut down the levels. But both this study and the last used emulsifier concentrations that weren't far in excess of what people might typically get day to day. This is probably the study that raised the greatest potential concern. The researchers surgically obtained not just cells, but actual intestinal wall tissue and found that polysorbate 80 could double the invasion of E. coli through the intestinal lining tissue, whereas adding fiber, in this case fiber from plantains, could seal up the gut wall tissue twice as tight.