Immune System & Gut Bacteria

A community of 100 trillion bacteria and over 5,000 different species of bacteria, as well as

viruses, fungi, and parasites are the permanent residents of the human GI system. The number of bacteria in the GI system is larger than the number of stars in the Milky Way galaxy. The number of stars in the Milky Way is between 100 and 400 billion. The gut bacteria or gut microbiota contain a significant portion of the immune system, about 70 to 80 percent of the body immune cells residing in the gut. The diet and environment have a significant impact on gut bacteria types. Gut microbiota disruption can cause GI system diseases such as inflammatory bowel disease and obesity.

Obesity is a significant risk factor for breast cancer especially in postmenopausal women. Fat

cells increase the level of estrogen. Obesity increase the level of insulin and insulin like growth

factors that promote cancer development. A balanced gut bacteria prevents weight gain and

chronic diseases such as heart disease, arthritis, and cancer. Gut bacteria break down food,

absorb vitamins and minerals, protect the body from diseases, control metabolism, and have a

crucial impact on the immune function. The highest concentration of the gut microbiota are

found in the colon that is the part of the large intestine. The most dense population of bacteria

digest complex carbohydrates, and provide a thick mucus layer like a protective wall in the colon.

The small intestine has a single unattached mucus layer but the stomach and colon have two

layers of mucus. The inner layer is attached and the outer layer is unattached and less dense. The colon outer mucus layer is the home for friendly bacteria. The inner mucus layer is impermeable and bacteria can not pass through but it is renewed every hour by epithelial cells that protect the inner and outer surface of the colon. The mucus-secreting cells have the ability to restore the mucus layer by secretion. Certain parasites and some bacteria have enzymes that can break down mucins and dissolve the mucus layers as part of their pathogenicity. When the inner mucus layer become penetrable, bacteria and pathogens can reach the epithelial surface that make the immune systems become defective and irregular. An irregular immune system triggers the inflammation.

A diet high in ultra processed food and high sugar can reduce the beneficial friendly bacteria.

The imbalance causes sugar craving, more permeability, inflammation, and further damage to the gut bacteria. Eating a high fiber diet allows the friendly bacteria to grow and increase the number and diversity. Fiber acts like a prebiotic that feeds the beneficial bacteria.