The Impact of Gut Microbiota on Digestion, Immune System, and Disease

It is estimated that the digestive tract contains trillions of bacteria. In recent years, research has shown that the gut microbiota is connected to healthy digestion, disease, and the immune system. It has become apparent that the bacteria in your gut is vital to the healthy function of the human body and maintaining a healthy and diverse gut microbiota is essential. While there are ways to help populate your gut with healthy bacteria through supplemental probiotics and the consumption of fermented foods, there are many more ways to weaken your gut microbiota through the consumption of antibiotics. Food additives like preservatives and emulsifiers are often overlooked in this discussion and could be more damaging to the gut microbiota than antibiotics.

The human digestive tract is home to thousands of species of bacteria. The average human gut contains trillions of bacteria and around 1000 species of bacteria. These bacteria have been identified to be crucial for digesting food and making their nutrients easier to absorb by the intestines. One study showed that certain species of Bacteroides that are found in 92 percent of humans, were responsible for digesting xyloglucans, which are found in some vegetables. The body does not naturally encode for any proteins that are made to digest xyloglucans, making these species of bacteria vital for digesting these substances that are abundant in various foods in the human diet.

Certain species of bacteria help breakdown indigestible dietary fibers into short chain fatty acids, which are an essential energy source for gut motility and coordinating intestinal immune responses. Various digestive disorders like irritable bowel syndrome and Crohn’s disease have responded positively to probiotic consumption and changes of the diet that are designed to limit foods containing certain types of carbohydrates and dietary fibers that feed some types of bacteria. In cases of individuals suffering from Clostridium difficile infections, fecal transplants have shown miraculous results. When the healthy fecal microbiota from a donor gets transplanted into the gut of a person with a C. difficile infection, there have been cases of symptoms disappearing immediately after the transplant.

The gut microbiota plays a significant role in our health, but we can easily disrupt the sensitive gut microbiota throughout the consumption of antibiotics and certain food additives. Antibiotics will kill any bacteria in the gut it is exposed to. This can eliminate many species of bacteria, along with damaging the total number of bacteria in the gut. This can cause harmful bacteria to overpopulate, disrupting the sensitive balance of the variety of bacteria present in the human gut. The use of several antibiotics such as penicillin, cephalosporins, fluoroquinolones, and clindamycin has been linked to C. difficile infections. C. difficile bacteria are common inhabitants in the human gut, but it is suspected that the use of antibiotics disrupts the balance of bacteria in the gut and the elimination of the beneficial bacteria by the antibiotics that keeps the C. difficile bacteria in check, leads to the overpopulation of the C. difficile bacteria.

Food additives like preservatives are often overlooked in this discussion. Preservatives are present in many food products to preserve the shelf life. A large percentage of non-fresh foods found in the supermarket contain some type of preservative. Some of these preservatives are sodium nitrate in cured meats, sodium benzoate in acidic foods like canned jams, and antioxidant preservatives like ascorbic acid and tocopherols. The antimicrobial preservatives like sodium nitrate and sodium benzoate act to preserve food by inhibiting the proliferation of bacteria and preventing the food from going rancid. If they are antimicrobial and prevent bacterial growth on food, what prevents them from having antimicrobial effects in the gut after it is consumed?

The effect of common antimicrobial preservatives have on the gut itself, but the suppression of bacteria on foods, which not only contain potentially harmful bacteria, but also good bacteria as well. This lowers the amount of good bacteria that gets consumed. One study of a food additive not involving preservatives may indicate the potential issues with non-antimicrobial food additives. In a study involving mice, where the mice were fed emulsifiers, which are commonly found in sauces, dressings, mayonnaise, and candies; caused intestinal inflammation and metabolic syndrome only after 12 weeks. It is believed that emulsifiers disrupt the mucous layer that lubricates and protects the lining of the intestine.

The gut microbiota is involved in various aspects of our health. It plays a huge role in the immune system and digestion of food. The plethora of good and bad bacteria balance each other out and prevents various diseases. When this balance is disrupted, you can potentially get an overgrowth of some of the harmful bacteria. This disruption can occur through the consumption of antibiotics and food additives like emulsifiers and preservatives. Many food additives are important to keep food fresh, but is probably a good idea to eat as much fresh food as possible and avoid food products with a laundry list of ingredients.