Digestion works like a giant food processor, using both mechanical and chemical means to break down the food you eat into nutrients suitable for your body to use. The digestive system consists of the alimentary canal and its related glands and organs. The alimentary canal is a hollow tube some twenty-seven feet long which goes from the mouth to the rectum. It normally takes 15-72 hours for food to pass through the alimentary canal. Your brain is in the first organ involved in digestion, and just the thought, sight or smell of food is enough for it to initiate the secretion of digestive juices and saliva.
Chewing is the second phase of digestion. The food is torn into smaller pieces for easier swallowing, and allows for the exposure of a greater surface to the digestive fluids. Chewing and swallowing are the only conscious acts of digestion. After that, the autonomic nervous system takes over and you’re on automatic pilot.
When you swallow, your esophagus (the portion of the alimentary canal between your mouth and stomach) propels each bolus, or portion of food, to your waiting stomach. Movement of gastrointestinal contents through the esophagus and problems encountered with IBS stem from an interruption in the normal timing and rhythmical action of peristalsis.
The stomach, which is the widest portion of the alimentary canal, serves as sort of a waiting room and preparation chamber. The stomach releases acids to assist in breaking down food particles; it also releases mucus to protect the stomach lining from acid burns. The stomach continues a rhythmical movement to mix the food with stomach acid, turning the food into a semi-digested material called chyme.
Through peristaltic movement, successive amounts of chyme enter the first part of the small intestine, called the duodenum. The small intestine is approximately twenty-one feet long in the average person. In the duodenum, chyme comes into contact with enzymes from the pancreas and bile from the gallbladder. The pancreas produces the enzymes protease, amylase, and lipase. These assist, respectively, in breaking down proteins into amino acids, complex carbohydrates into simple sugars and fat into fatty acids. Bile acid acts as an emulsifier by dividing fats into smaller particles that will become suspended in water, allowing these particles to be absorbed more easily.
Moving along through the ileum and jejunum the nutrients that have broken down from our food become absorbed in the remainder of the small intestine. The small intestine contains many folds and fingerlike projections called “villi”. Damage to the small intestinal villi can occur as a result of such things as a sensitivity to gluten or other foods and pathogenic or disease causing microorganisms.
Think of the villi as the roots of a plant. Damage to the villi, or your bodies root system, can lead to a wide range of nutrient deficiencies and chemical imbalances.
All of the blood flow from the small intestine goes to the liver for further processing and detoxification. The indigestible parts of your food move from the small intestine into the approximately three feet of colon or large intestine. The colon serves as sort of a drying tank, absorbing excess water so that under normal circumstances a formed stool can be created for elimination.
Digestion is a complex process whereby your body takes the food you ingest and extracts the nutrients to nurture your body. Always try and eat a nutrient dense, whole food diet.
About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.