Our Internal Ecosystem
Our bodies are constructed from the products of our digestion – we literally are what we eat. With that in mind, think of the digestive tract as an entire ecosystem, a self-contained environment supporting a community of hundreds of species of bacteria. This ecology consists primarily of friendly bacteria at work, our digestive flora. Without these beneficial bacteria to ferment and digest our food, we can’t have complete digestion or healthy bodies.
The immune system in our digestive tract performs the tremendous task of distinguishing friend from foe in this internal world, playing traffic cop to more than 500 species of bacteria. Most of these are friendly, but even in a healthy digestive tract small numbers of destructive microbes are always present. We also consume a wide range of bacteria, yeasts, and molds in our food and water; some of these microbes can be harmful if they survive and flourish.
The protective mechanisms of our GI tract are designed to neutralize these common organisms. A significant portion of our immune function is strategically located in the GI tract to keep a favorable balance between the helpful and destructive organisms. This immune function is so vital that 50 percent of the lymph tissue in the body is located in the intestinal lining and 80 percent of all our protective antibodies are produced there. In short, the body devotes an enormous amount of energy to maintaining the proper balance in the digestive system.
When the Balance Is Lost
A number of influences can upset this elegant balance:
• Overgrowth of yeast, including candida
• Overgrowth of undesirable bacteria
• Microscopic parasites
• Parasites such as worms
• Viral illnesses
• Poor hygiene
• Bad water
• A starchy diet
• Too many sweets
• Excessive alcohol intake
• Food allergies
• Certain medications
• Frequent use of antibiotics
• Physical injury
• Genetic tendencies
• Environmental toxins
The bacteria in our GI tract number in the trillions. A healthy adult has five to eight pounds of living bacteria in their digestive tract, most of which are beneficial. These bacteria perform an essential part of our digestive function and we are completely reliant on their activities. This huge engine of fermentation produces the nutrients essential to our functioning.
Previously it was thought that the cells lining the GI tract were nourished by our body through the blood supply. However, recent research has shown that it is the beneficial bacteria that nourish the digestive tract (for example, they produce essential short-chain fatty acids). A number of other important nutrients are also available only through the bacterial fermentation of our food. Without the nutrients from these bacteria, there is a loss of function in the lining of the gut. (This can occur whenever we take antibiotics, unless we replenish the bacteria afterward with probiotics).
When the flora is compromised or the immune system weakened, destructive bacteria or yeast that happen to be in residence may not be held in check. Then colonies of the harmful organisms (pathogens) can establish themselves in numbers great enough to disturb the intestinal environment and harm the body. This imbalance in the microorganisms of the digestive tract is called dysbiosis.
If the friendly flora are compromised, the intestinal lining can become malnourished, because the supply of vital nutrients is diminished. What’s worse, the destructive microbes produce toxic chemicals that can cause tissue damage in the GI tract and elsewhere in the body. The immune system may then become further impaired.
The ultimate priority of the GI tract is to contain (and dispel) the substances that are toxic and to admit the nutrients our bodies require. To accomplish this, the gut membrane acts as a selective barrier. This is the single most important activity of the digestive tract. These functions – containing toxins and absorbing nutrients – use an incredible amount of our energy. Digestive activities include regulating and accepting just the nutrients needed and rejecting everything else. And most of the material in the GI tract is rejected – very little is actually absorbed. You can see why the breakdown of these protective systems can cause a toxic condition in the body, a condition referred to as leaky gut; it can also create the potential for illness.