Thursday, July 22, 2010

Your Digestive System and Its Importance to Your Health

Today we're going to discuss a fascinating topic involving what happen to foods and drinks once they enter your body. We will start from when you put a morsel of food or a sip of liquid in your mouth, to when it passes out as feces or urine.

Foods and drinks are of little value to the body except for the digestive system which breaks them down into smaller molecules that are absorbed into the blood, and carried to all parts of the body to repair and nourish cells and provide cellular energy.

Digestion begins in the mouth. When you begin chewing a piece of bread or meat, the mucosa lining of the mouth produces digestive juices that break the food down into a mixture that is pushed down through the esophagus by peristalsis or a wavelike movement toward the stomach.

Once the swallowed food and drink enter the stomach through the esophageal sphincter, digestive juices produced by the stomach are added, to be thoroughly mixed by the muscle movement of the lower part of the stomach. The mixture now in semi-liquid form, is emptied from the stomach into the small intestine.

As the semi-liquid mixture enters the small intestine, the absorption of nutrients in their simpler molecular form begins. For instance, carbohydrates from bread, potatoes, dried peas and beans, rice, pasta, fruits and vegetables are first broken down to search and sugar. Fibers from carbohydrates are broken down into soluble and insoluble fibers.

Enzymes in the saliva, and in the juices produced by the pancreas break down starch into maltose. Then enzyme from the mucosa lining of the small intestine splits the maltose into glucose molecules that can be absorbed into the blood. Sugar is also broken down by intestinal enzymes to glucose and fructose that are absorbed into the blood. The smaller molecules of both sugar and starch are carried to the liver to provide energy for cellular activities.

Foods such as fish, meat, eggs and beans have large molecules of proteins that cannot be absorbed directly into the blood. Enzymes in the digestive juices of the stomach start the breakdown of these huge protein molecules, then additional juices from the pancreas and mucosa lining of the small intestine complete the breakdown into smaller molecules called amino acids before they can be absorbed into the blood, and used to build and repair the walls and other parts of cells.

Foods cooked with saturated and trans fats, monounsaturated and polyunsaturated fats and butter or margarine are the major sources of fats for the body. Fats are dissolved into the watery content of the intestine by bile acids from the liver that allow enzymes from the pancreas and small intestine to break large fat molecules into smaller ones like fatty acids and cholesterol.

Since fats are also a source of energy for the body, excess fats are retained for future use. To do this, bile acids attach themselves to the fatty acids and cholesterol and carry them into the mucosa cells of the small intestine. While in the cells, the smaller fat molecules are reformed into large fat molecules, most of which are carried by lymphatic vessels to the veins of the chest, from where the large fat molecules are carried by the blood to storage areas in the body. This explains  why people who eat lots of saturated and trans fat are overweight.

Vitamins are another molecule of nutrients from food that are absorbed through the small intestine into the blood for distribution to all parts of the body. Vitamins are either soluble as in all B and C vitamins, or fat-soluble as in vitamins A, D, E and K. Fat-soluble vitamins are stored in the liver and fatty tissue of the body, but soluble vitamins are hard to store, and excess amount are flushed out in the urine.

Water and mineral salts are also molecule of nutrients absorbed into the blood. The body's essential mineral salts include sodium, phosphorus, potassium, chlorine, sulfur, magnesium and calcium. Smaller elements of these such as iodine, iron, fluoride and zine are absorbed directly into the blood. Sources of mineral salts include fruits, vegetables and sea foods, liquids and the juices secreted by the digestive glands. Salts deficiency cause insomnia, fatigue, anemia and osteoporosis. 

At the end of the digestive process wastes are produced which include undigested parts of foods such as fibers, and dead cells shed from the mucosa lining. These waste products are pushed into the colon where they remain until they are expelled from the body as feces.

You will note that the digestive system breaks down foods and drinks to their smallest molecule of nutrients and mineral salts that can be absorb into the blood. Once in the blood the final destination of these are the cells. Why are the cells so important? They are important because they give form and life to all the organs and tissues in your body. Which is why to remain healthy, you need a healthy digestive system to extract the essential nutrients and mineral salts your cells need to function optimally.

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