Thursday, December 8, 2011
The digestive system essentially converts the foods that we eat into the energy needed to support life.
Properly balanced diet
The digestive process and maintaining good health depends on a properly balanced diet. The digestive system essentially converts the foods that we eat into the energy needed to support life. The anatomy of the digestive system process involves a complex series of organs and glands that work in concert to break down our consumed foods into smaller molecules that can be utilized by the body.
The digestive process
The digestive process begins in the mouth where food is partially broken down by the process of chewing and by the enzymatic action of the carbohydrate-digesting amylase enzymes present in the saliva. Food is then swallowed and makes its way down the esophagus to the stomach.
In the stomach, food is mixed, ground and digested by gastric acid and a protein-digesting enzyme called pepsin. Gastric acid is an important part of the digestive process, consists mainly of hydrochloric acid (HCl), and it very efficiently breaks down food material, particularly protein. If production of gastric acid decreases (as is often the case with advancing age), the digestive process is less efficient. Researchers in the U.S. found that over 30 percent of men and women past the age of 60 suffer from atrophic gastritis, a condition marked by little or no gastric acid secretion (1).
Fortunately, natural approaches and nutritional supplements can help support an optimal digestive process in the stomach.
The partially digested food leaves the stomach and continues through the digestive process by entering the small intestine, a tubular structure composed of three segments: the duodenum, jejunum and ileum. The duodenum continues the digestive process of breaking down food with the aid of bile from the gallbladder and enzymes released by the pancreas and the duodenal walls. Bile causes a breakdown of fat from large to smaller globules. Further digestion of fats, protein and carbohydrates takes place with the help of the pancreatic enzymes lipase, trypsin and amylase, respectively. Nutritional supplements can help support small intestinal digestive action.
The digestive process is basically complete once food passes through the duodenum. Absorption of nutrients into the bloodstream takes place in the jejunum and ileum segments of the small intestine. After absorption of food molecules into the bloodstream, the blood is purified by the liver to remove harmful substances. The liver also stores fat-soluble vitamins (vitamins A, D, E and K) and excess glucose for future use. Digestive supplements can be used to support these valuable liver functions.
The importance of fiber and friendly bacteria
The large intestine receives mostly indigestible material and water from the small intestine. Excess water and any residual minerals are absorbed in the large intestine. Fiber aids the process of moving the remaining debris through the large intestine, thus easing the passage of waste known as a stool. In addition to promoting elimination, fiber also helps to support friendly bacteria. About 100 trillion bacteria contribute to the digestive system process. These bacteria in the large intestine perform several essential functions. Probiotics, as these bacteria are called, promote an efficient digestive process, support the immune system, inhibit the growth of pathogenic microorganisms, and produce several vitamins. Many supplement products consist of soluble and/or insoluble fiber from a variety of plant sources. Additionally, many different bacterial species found in nutritional supplements are capable of functioning as probiotics.
Probiotics have long been known to provide many benefits to the digestive system process and overall human health as mentioned in the previous paragraph. I have read with great interest several recent research reports on some additional actions that are very different from what you would expect. One example is an experiment where mice, fed broth containing Lactobacillus rhamnosus, behaved less anxiously than mice fed broth without bacteria. These behavioral changes were partially explained by differences in brain chemical receptors and stress hormone (corticosterone) levels. The overall observation was that a change in the mix of intestinal bacteria provided by L. rhamnosus influenced mouse behavior by way of the vagus nerve. The vagal impulses induced by the microbes resulted in an increase in GABA (gamma amino butyric acid, which is a neurotransmitter or brain chemical) receptors in the brain and lower levels of stress hormone. The net result was a significant decrease in anxiety observed in the mice receiving the bacteria-containing broth (2).
Just a few years ago, most scientists were of the opinion that probiotics only acted locally in the gut. However, this study suggests that gut bacteria could play a role in various brain and psychiatric disorders as well as individual behavioral differences.
Inflammatory Bowel Disease (IBD)
Another fairly intense research area involves how intestinal microbes contribute to or counteract chronic inflammation and affect the digestive system process. As we all know, chronic inflammation is associated with many disease states. Inflammatory Bowel Disease (IBD) is one of these conditions that appears to be directly influenced by specific probiotic species. It was interesting to read that those probiotic strains that specifically keep IBD in remission do not function normally in the presence of an iron-rich environment (3). Species of Lactobacillus and Bifidobacterium were found to be inhibited by high iron levels and this resulted in a failure to reduce inflammation. These research data suggest plausible explanations as to why IBD becomes established. As this probiotic research continues, valuable therapies will eventually emerge. Of equal importance here is that we will have a greater understanding of the digestive system process and health.
Created by Dr. William J. Keller
Krasinski SD, Russell RM, Samloff IM, Jacob RA, Dallal GE, McGandy RB, Hartz SC. Fundic atrophic gastritis in an elderly population. Effect on hemoglobin and several serum nutritional indicators. Journal of the American Geriatrics Society. 1986 Nov;34(11):800-6.
Bravo JA, et al. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences of the United States of America. 2011 Sep 20;108(38):16050-5.
Bailey JR, Probert CS, Cogan TA. Identification and characterisation of an iron-responsive candidate probiotic. PLoS One. 2011;6(10):e26507.