Study Shows Food Additives Alter Gut Microbes and Cause Diseases in Mice
by Dr. Thomas K. Lo
Our digestive tract is home to 100 trillion bacteria, collectively known as the gut microbiota. These bacteria help with metabolism and maintaining a healthy immune system. Changes in this microbial community can cause chronic diseases.
The National Institute of Health (NIH) reported that a study on food additives (also called emulsifiers) promoted colitis and metabolic syndrome in mice by altering gut microbes. These emulsifiers—detergent-like food additives found in a variety of processed foods—have the potential to damage the intestinal barrier, leading to inflammation and increasing our risk of chronic disease. Emulsifiers are used because oil and water will not mix until an emulsifying agent is added. Emulsifiers made from plant, animal, and synthetic sources are often added to processed foods such as mayonnaise, ice cream, and baked goods creating a smooth texture and preventing separation while extending shelf life.
The findings of the study suggested that certain food additives might play a role in the increasing incidence of obesity and chronic inflammatory bowel disease. The research was funded in part by NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Findings appeared in Nature on March 5, 2015.
The research team lead by Dr. Andrew T. Gewirtz, professor of biology at Georgia State University, studied the thick layer of mucus that separates gut bacteria from the lining of the intestine. The team wondered whether chemicals that disrupt this mucus barrier might alter the gut microbiota and play a role in disorders associated with inflammation, including inflammatory bowel disease and metabolic syndrome.
“What we’ve been attempting to understand for the past several years is the increase in metabolic syndrome and inflammatory bowel diseases that affect digestion,” explains Gewirtz. Metabolic syndrome includes obesity, increased risk for Type 2 diabetes, and cardiovascular diseases like heart attacks and strokes. All these conditions, Gewirtz explains, “are associated with changes in gut bacteria.”
The recent, dramatic increase in metabolic-related diseases cannot be attributed solely to genetics, says Gewirtz. Human genetics haven’t changed in recent decades. Therefore, he and his colleagues set out to investigate environmental factors that might be responsible, including “modern additions to the food supply.”
Previous research suggested that emulsifiers could be implicated. For the new study, researchers fed mice emulsifiers in either their water or food. The experiment used polysorbate 80 (found in ice cream, sherbet, mayonnaise, and salad dressing) and carboxymethylcellulose (found in ice cream, dressing, cheese, icing, toppings, gelatinous desserts, infant/baby formula, candy, cottage cheese, and cream cheese spread) and found that it altered microbiota in a way that caused chronic inflammation. They tested the emulsifiers at levels below those approved for use in food and at levels modeled to mirror “what a person would eat, if they eat a lot of processed food.”
Mice with abnormal immune systems fed emulsifiers developed chronic colitis. Those with normal immune systems developed mild intestinal inflammation and a metabolic disorder that caused them to eat more, and become obese, hyperglycemic, and insulin resistant.
The inflammatory response prompted by eating emulsifiers, explains Gewirtz, appears to interfere with “satiety” (a state of being completely full, someone who has eaten enough) and can lead to overeating. The mice experiencing this inflammation developed more fat.
Gewirtz explains that the emulsifiers appear to disturb both the bacteria normally present in the gut and the gut’s protective mucus layer. The chemistry of the emulsifiers seem to change the microbiota and how these bacteria interact with the intestine itself. The combination, Gewirtz says, sets the stage for inflammation. He is quick to say that these food additives are by no means the “only cause of the obesity epidemic or inflammatory bowel disease.” However, emulsifiers may be a factor contributing to excess eating. The results showed that changes in the gut microbiota caused by dietary emulsifiers could drive inflammation and metabolic changes.
“We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome,” said Gewirtz. However, these results suggest that modern additions to the food supply can interact with gut microbiota to influence inflammation, metabolism, and weight.
Probiotics are live microorganisms (e.g., bacteria) that are either the same as, or similar to, microorganisms found naturally in the human body and may be beneficial to health. If you picture the human body as a “host” for bacteria and other microorganisms, you might have a better understanding of probiotics. The body, especially the lower gastrointestinal tract (the gut), contains a complex and diverse community of bacteria. Although we tend to think of bacteria as harmful “germs,” many bacteria actually help the body function properly.
Probiotics are available to consumers in oral products such as dietary supplements and fermented foods, such as kimchi, kombucha, sauerkraut, miso, and kefir. Because of how they are prepared, they contain microorganisms that boost the diversity of good bacteria, yeasts, and fungi living in our guts.
Probiotics also might lower the number of “bad” bacteria in your gut that can cause illness or inflammation. They also can replace those problem germs with good or helpful bacteria.
Researchers are studying when and how probiotics might best help. There is some evidence that probiotics may be helpful for acute diarrhea and antibiotic-associated diarrhea. Controlled trials have shown that Lactobacillus GG can shorten the course of infectious diarrhea in infants and children.
Although studies are limited to large reviews, taken together, suggest that probiotics reduce antibiotic-associated diarrhea by 60 percent, when compared with a placebo. More common than diarrhea is the opposite problem of constipation. Researchers have found that probiotics increase the number of weekly bowel movements by 1.3, and probiotics help to soften stools, making them easier to pass.
Probiotic therapy may also help people with Crohn’s disease and irritable bowel syndrome. Clinical trial results are mixed, but several small studies suggest that certain probiotics may help maintain remission of ulcerative colitis and prevent relapse of Crohn’s disease. Because these disorders are so frustrating to treat, many people are trying probiotics before all the evidence is in for the particular strains they are using.
Harboring a flourishing gut flora has been linked to lower obesity, fewer autoimmune conditions and digestion problems, longer lifespan, good brain function, and happiness in some studies.
It is important to be aware that the U.S. Food and Drug Administration (FDA) has not approved any health claims for probiotics.
If you are struggling with some of the symptoms mentioned in this article or other health issues, call the Advanced Chiropractic & Nutritional Healing Center at 240-651-1650 for a free consultation. Dr. Lo uses Nutritional Response Testing® to analyze the body to determine the underlying causes of ill or non-optimum health. The office is located at 7310 Grove Road #107, Frederick, MD. Check out the website at www.doctorlo.com.