A study on mice showed that emulsifiers can disrupt intestinal bacteria to cause inflammation and weight gain (Nature, Feb 25, 2015). Emulsifiers are added to many foods, such as ice cream, salad dressing, pastas, bread and cookies, to prolong shelf life and keep ingredients from separating. If these same results are found in humans, emulsifers may be shown to increase risk for inflammation, ulcerative colitis, Crohn’s disease, weight gain, central obesity, insulin insensitivity, and diabetes.
Researchers fed the emulsifiers carboxymethylcellulose and polysorbate-80, at doses comparable to what humans eat in processed foods, to mice for 12 weeks. The mice's gut bacteria penetrated into the intestinal lining, instead of staying on the surface where they belong. This turned on their immunity against these bacteria, as demonstrated by making proteins that are signs of an overactive immunity (inflammation). They also gained a lot of extra weight. Another group of mice that had been treated to have no gut bacteria had none of these effects when fed the emulsifiers. When researchers transplanted bacteria from the original group of mice into the group with no previous bacteria or symptoms, the recipient mice developed all the same changes exhibited in the original group, which showed that the emulsifiers had changed the gut bacteria.
Application of This Study to Humans
Your intestines contain more than 100 trillion bacteria (about four pounds). The bacteria are prevented from piercing your intestines by a thick mucus layer that covers the entire inner lining. Emulsifiers are detergent-like molecules that can break down this thick mucous layer and allow the bacteria to penetrate the inner linings of your intestines. Your immune system responds to these invading bacteria by producing all the chemicals that it uses to kill germs and prevent infections. This overactive immunity, called inflammation, may be the cause of the marked increase in inflammatory bowel diseases (ulcerative colitis and Crohn’s disease) that has occurred in the last 70 years.
Emulsifiers can also cause blood sugars to rise to high levels and increase the absorption of foods. The emulsifiers made the mice fat (particularly in their bellies), prevented them from responding to insulin and caused them to develop diabetes. We do not yet know whether the same results occur in humans.
What are Emulsifiers?
Emulsifiers hold food ingredients together. Mayonnaise without emulsifiers would separate into an oily top layer and a thick white bottom layer. Foods that may contain emulsifiers include margarine, mayonnaise, salad dressings, creamy sauces, candies, ice cream, fast-food shakes, baked goods and many other processed foods. Emulsifiers are also found in a large number of the prescription and over-the-counter drugs on the market today. They are used to improve the consistency of gel capsules, make pills dissolve in the stomach, and keep medication suspended in liquid form.
What Does This Mean for You?
This is a well done study that should make you think about eating processed foods that have lots of added chemicals, many of which have never been tested for consequences in humans. If future studies confirm this one, you will want to avoid emulsifiers. In general, it is more healthful to eat foods as they are found in nature, such as fruits, vegetables, nuts, beans and other seeds, and to restrict foods that have been processed with added chemicals.