Do Gut Microbes Dislike Processed Foods?
Throughout history, innovations in science, medicine, and clothing have improved the quality of life, making it more efficient, convenient, safe, and fashionable. During session 092, “What Conventional Toxicology Doesn’t Tell You: The Impact of Processed Foods on Gut Microbiota, Inflammation, and Metabolic Disease,” Andrew Gewirtz of Georgia State University said that innovations solve problems, but sometimes they cause new problems. He used partially hydrogenated of oils as an example: Nobel Prize winner Paul Sabatier developed the process of oil hydrogenation, which was used to create margarine, which addressed a butter shortage and storage issues. For many years, margarine seemed like a great idea until it became clear that partially hydrogenated oils contain trans fats, which increase the risk of developing cardiovascular disease. Gewirtz, who studies the causes of intestinal inflammation, believes that emulsifiers in processed foods may be following a similar trajectory.
According to Gewirtz, intestinal bacteria make up a mucosal immune system and are essential for health, but they can also act as “one’s BFF: best frenemy forever.” Numbering in the trillions, the bacteria residing in the intestines—the gut microbiota—play a role in inflammatory bowel disease, metabolic syndrome, and obesity. Normally, the mucosal immune system of the gut expediently detects and clears pathogens, but Gewirtz’s research indicates that dietary factors can impede that process. His studies on mice show that the composition of gut microbiota can predict whether an individual is lean or obese with 90% accuracy (in comparison, genetic composition provides only 60% accuracy). Gewirtz therefore believes that low-grade inflammation induced by gut microbiota can take a classic form (e.g., colitis) or manifest itself as obesity and metabolic disease. But are Gewirtz’s research findings relevant to humans? Preliminary evidence suggests they are.
In humans, factors such as antibiotic uses, hygiene, loss of parasites, and absence or presence of viruses can affect the environment of the gut microflora. Dietary factors may also play a role, particularly the emulsifiers that are commonly used to improve the texture and homogeneity of foods such as ice cream. To prove his theory, Gewirtz and his research team again performed experiments on mice, adding the emulsifiers carboxymethylcellulose and polysorbate 80 to their food. Although still in its early stages, Gewirtz’s research indicates that emulsifiers increase the amount of gut bacteria invading the epithelium of the colon, which causes inflammation and changes the composition of microbiota. Moreover, the mice who were fed emulsifiers developed obesity and metabolic syndrome. Although humans are not mice, Gewirtz said that this evidence combined with examinations of human intestines suggests that the emulsifiers that make ice cream so creamy may make one’s intestinal neighborhood not so dreamy.