The bacteria in the lower intestine have evolved over thousands of years to feed on and extract nutrients from the dietary fiber that our primary digestive processes cannot digest. In a sense, they are scavengers but it is perhaps more accurate to say that we are eating to feed two digestive systems – the one that processes proteins, simple carbohydrates and fats and the one that processes complex carbohydrates or fiber.
If the human biome didn’t provide us with solid benefits then it might be OK if we didn’t feed it. However, the reality is that these bacteria are vital to our health and well being. In addition to extracting added nutrition from dietary fiber they constantly monitor the blizzard of bacteria that enter our bodies through our mouths. Those that are friendly and can live in the anaerobic (oxygen free) environment on our large intestine are given a chance to join our diverse gut community while those that are harmful are attacked and eliminated. The biome then passes on what it has learned about the invading bacteria to our immune system. In ways that are not yet fully understood the biome also triggers the production of enzymes that play a vital role in everything from our mental health to our appetite and metabolism.
The evolution of Western diets toward more fats and carbohydrates and less fiber has left our microboimes undernourished and in extreme cases driven to cannibalistic behavior just to survive. When that happens we lose the helpful byproducts from the Micro Biome’s digestion of dietary fibers and drive our gut bacteria to subsist on the mucous membrane that lines our large intestine. That membrane is in place to act as a barrier between the good and bad bacteria in the colon and the rest of our body. When it is cannibalized due to the lack of fiber in our diet then the inner wall of the colon is exposed to attack and some toxins seep into our blood stream. The unhappy results can include Irritable Bowel Syndrome, Colitis, Crohn’s Disease and a breakdown of our immune response to a variety of health threats.
Fortunately, dietary fiber is the preferred diet of gut bacteria. If we feed them what they like with a regular diet that is rich in dietary fiber then they are our allies and not our enemies. They produce that short chain fatty acids that contribute to the maintenance of the mucous membrane, interact with our immune system to flag potential threats and produce a wide variety of enzymes that contribute to our physical and mental health.