It is estimated that some form of digestive disorder affects more than 100 million people in America. For some people, digestive disorders are a source of irritation and discomfort that may cause them to drastically limit their lifestyles and frequently miss work. For others, the disorders may be extremely crippling and even fatal.
The Gastrointestinal Tract
The gastrointestinal (GI) tract is a long muscular tube that functions as the food processor for the human body. The digestive system includes the following organs: mouth and salivary glands, stomach, small and large intestines, colon, liver, pancreas, and gallbladder.
Irritations or inflammation of the various sections of the GI tract are identified as gastritis (stomach), colitis (colon), ileitis (ileum or small intestines), hepatitis (liver), and cholecystitis (gallbladder).
The GI tract is not a passive system. Rather, it has the capability to sense and react to materials passed through it. For a healthy digestive system, every person requires different food selections that match their GI tract capacity.
The Digestive Process
The GI tract breaks down foods by first using mechanical means (e.g., chewing) and then via the application of a host of complex chemical processes (from saliva to colon microbes). Since the GI tract is the point of entry for the human body, everything eaten has an impact on the body. The food eaten and passed through the GI tract contains nutrients as well as toxins. Toxins can include, but are not limited to, food additives, pesticides, and specific foods that induce a reaction from the GI tract.
The process of digestion is accomplished via the surface of the GI tract using secretions from accessory glands. The two glands providing the majority of digestive chemicals utilized by the GI tract are the liver and the pancreas. The function of the liver is to control the food supply for the rest of the body by further processing the food molecules absorbed through the intestines. The liver does this by dispensing those food molecules in a controlled manner and filtering out toxins that may have passed through the GI tract wall.
Another very important function of the GI tract is as a sensory organ. By rejecting foods through objectionable taste, vomiting, diarrhea, or any combination of these symptoms, the sensing capacity of the GI tract can protect the body. The surface of the GI tract has a complex system of nerves and other cells of the immune system. The surface of the GI tract, or mucosa, is part of a complex sensing system called the mucosa-associated lymphatic tissue (MALT). The immune sensors in the MALT trigger responses such as nausea, vomiting, pain, and swelling. Vomiting and diarrhea are abrupt defensive responses by MALT when it senses foods with a strong allergic or toxic component. This kind of food intolerance is responsible for many digestive problems. The GI tract is "hard-wired" to the brain via hormonal, neurotransmitter-mediator chemical communication.
The GI tract is a muscular tube that contracts in a controlled rhythm to move food through the different sections (peristalsis). Strength and timing variations in contractions can cause cramping (very strong contractions) and diarrhea (very frequent contractions). When the contractions are slow and irregular, constipation may occur. Motility Disorder is the general term used to describe problems with peristalsis.
Food allergy is sometimes the primary cause of GI tract problems. Chronic diseases can have their origin in food allergies. The dysfunction, discomfort, and disease associated with the GI tract can be the result of local immune responses to food selections or combinations of foods. Food selections are a result of personal tastes, social fads, ethnic culture, religion, and, to a larger degree, local or seasonal availability. Food selections made in modern affluent society are based on a developed taste for a rich diet centered on meats and dairy products loaded with fats, high concentrations of proteins, and fat-soluble toxins. Advertising and misinformation about healthy diets have overshadowed human nutritional needs.
Chewing, swallowing, and peristalsis comprise mechanical digestion, in which food is broken down into tiny particles, mixed with digestive juices, and moved through the digestive tract. Digestive enzymes break down large food molecules into small molecules that can be absorbed into the blood or lymph in the process of chemical digestion (Anatomical Chart Company® 2002; Lippincott Williams & Wilkins).