Every system of your body is vitally important to your health, but you have more control over your digestive system than you do over any other. Your heart beats and your lungs take in and expel air throughout your lifetime. These systems are termed autonomic (think automatic) systems because they are programmed to run automatically, Of course, how well your cardiovascular and respiratory systems function does depend in large part on your lifestyle choices, but you don't have to make a conscious effort to start your heart every morning when you wake up, and you don't have to remember to breathe. Your gastrointestinal tract is different. Once you swallow a bite of food, your body takes over the digestive process and runs automatically. With the exception of dangerous microbes that you can't avoid, what you put in your mouth is under your personal control. Your body is composed of about 75 trillion cells. Every cell-from the largest four foot-long nerve cell to the smallest sperm cell requires nutrients to provide the fuel it needs to do its work. Each cell is fueled by the nutrients present in the food you eat; they are dependent on you for the materials they need to build, repair, maintain, and control every system in your body. In 1987, the USDA funded a study to find out if the average American was eating a diet that provided ten essential nutrients. Out of the 21,000 people who participated in the study, not one was taking in the Recommended Daily Allowance (RDA) of the ten targeted nutrients considered essential for good health.


Our gastrointestinal tract is a long passageway that begins at your mouth and ends at your anus. It is both a food processor and a fueling station. Fuel equals energy, and this is where the energy to run your body comes from. Nutrients are processed here and passed on to fuel your cells. Your gastrointestinal tract also functions as a trash compactor and waste disposal system. After the nutrients are extracted from food and the water is reabsorbed, the compacted mass of "trash" leaves the body as faeces. In addition to these important duties, this is also where the friendly bacteria - your first line of defense - live and work. You should know what goes on in your gastrointestinal tract and just why it is so important to your health and longevity. So in order to understand the importance of probiotics, let's first look at how the gastrointestinal tract functions. 


The full length of the human digestive tract, from entrance to exit, is five to six times the height of the individual. Using five-and-a-half times as the norm, this means that the digestive system of a three­ foot-tall toddler is around sixteen- and-a-half feet, and the gastrointestinal tract of a six-foot-tall adult is thirty-three feet long. It's hard to believe that almost all of that "tubing" is tucked inside your abdomen, but it is. When you take a bite of food, the route that the food travels from your mouth into your throat, through your esophagus, and into your stomach is a straight highway; but there are many curves ahead. Your small intestine curves around and doubles back on itself-several times before it passes material into your large intestine. Your large intestine then goes up your right side, passes under your stomach and pancreas, and comes back down your left side, where it meets the rectum and anus. The tract contains around 200g of friendly bacteria that help break down your food. If these levels get depleted, then probiotics will be essential to restoring your gut health.


Before you take the first bite of food, your "food processor" is ready for action. First, the mechanical action of your teeth grinds the largest chunks into a fine paste. Digestion immediately begins in your mouth, where the sight and smell of food causes your salivary glands to begin producing digestive enzymes. It is this enzyme-filled saliva that starts the chemical break­ down of food into the simple, basic nutrients your body can use. Once you swallow, food travels through your esophagus, which is about ten inches long in the average adult, and passes into your stomach. This takes only around ten seconds. The "friendly" probiotic bacteria known as Lactobacillus reuteri is present in the mouth, where it helps fight bad bacteria that cause decay.


If you were able to open your stomach up fully, and then carefully smooth out all the billions of tiny wrinkles in its lining, its surface area would actually cover a tennis court! Compare your stomach to an elastic bag. After a big Chinese New year dinner, for example, it can stretch to hold two-and-a-half pints of food. The next time you're cleaning veggies in your sink, take a look at just how much space two-and-a-half pints takes up. It's not a good idea to force your stomach to stretch to accept this much food very often, because it puts a strain on your digestive system. Even before you swallow, digestive juices fill your stomach as it readies itself to accept the coming food.

When the food reaches your stomach, the stomach muscles begin to expand and contract, churning the food and mixing it well with digestive juices. Food remains in your stomach from two to four hours while this process takes place. Glands in the stomach wall release digestive enzymes and hydrochloric acid. This specialized acid not only assists in the digestive process, it also helps kill off most unhealthy bacteria. Other stomach glands produce mucus to protect your stomach wall from being burned by the acidic digestive juices. It was once thought that too much acid caused the holes in the stomach wall known as ulcers. Today, we know that most ulcers are caused by Heliobacter pylori, a bacteria that burrows into the stomach lining, causing inflammation in that area. Fortunately, your friendly probiotic Saccharomyces boulardii can help protect you from H. pylori and other bad bacteria that can cause stomach ulcers.


You might be surprised to know that most of the work of the digestive tract does not take place in the stomach, but in the small intestine. In the average adult, this section of tubing is about twenty-one feet long. It is divided into three areas that join one another - the duodenum, the jejunum, and the ileum. The walls of the small intestine are not smooth. Despite the length of this part of the gastrointestinal tract, a smooth surface would not provide enough surface area to complete digestion. Millions of tiny hair-like filaments called villi line the intestinal walls. These miniature projections wave back and forth like plants in an aquarium, capturing nutrients from the food as it passes through the small intestine, Each villus has its own network of capillaries, the tiniest of blood vessels. Amino acids and simple sugars pass through the walls of the villi and into the capillaries, finally entering the bloodstream. The villi also have a vessel connected to the lymphatic system, which is yet another transportation system for liquids. Even when completely broken down, fat molecules are too large to travel through the tiny capillaries, so they travel through lymph vessels Instead.

The Duodenum: At the upper end of the small intestine, a C-shaped section called the duodenum receives digestive juices directly from the pancreas, liver and gallbladder. Without the help provided by these glands, the digestive process would fail.

The Pancreas:

The pancreas secretes both digestive juices and the hormones insulin and glucagon. Coupled with hormones from other endocrine glands, the pancreatic hormones play a primary role in the regulation of carbohydrate metabolism. When the pancreas secretes insufficient insulin, the result is diabetes mellitus. When it puts out too much insulin, the result is hypoglycemia, or low blood sugar. Every day, the pancreas secretes one to two pints of enzyme-rich digestive juices into the duodenum. These juices are important for the digestion of alI types of food, especially carbohydrates. The pancreatic juices continue the breakdown of carbohydrates into sugars that started in the mouth. The liver then converts these sugars into glucose, the blood sugar used by the body for energy. Other pancreatic enzymes continue working on the breakdown of proteins and fats that began in the stomach.

The Liver:

The liver is your largest internal organ, weighing between three and four pounds in the average adult, The liver receives its blood supply from two sources, the heart and the small intestine. The heart provides approximately one-fifth of this blood, which is oxygenated, while the remaining nutrient-rich blood comes from the pancreas. A major part of the digestive system, the liver plays other important roles as well. For example, it breaks down old red blood cells and processes potential poisons for removal from the body. These poisons include nicotine and alcohol, which the liver can process in small amounts, and drugs that have served their purpose. It also detoxifies certain harmful substances produced in the intestines, such as phenols and ammonia, which it turns into urea, one of the compounds found in urine. Another vital function performed by the liver is storage. Carbohydrates in the form of glycogen remain in the liver until energy is called for by the brain, muscles, and organs; then the glycogen is converted into glucose and transported to where it is needed. This function is especially important to your brain, since it cannot store glucose. In order for you to think properly, your brain depends on the steady supply of glucose energy that your liver provides. The liver also processes proteins, vitamins and many uther compounds used by your body. To do it's part in the digestive process, the liver produces a thick, greenish fluid called bile, which makes the digestion of fats possible by making them water-soluble. Bile is stored in the gallbladder until needed. When you eat a fat-laden meal, your liver prepares for the onslaught by filling the gallbladder with extra bile.

The Jejunum and Ileum

Once the important work by the pancreas and liver is complete, the partially digested food passes from the duodenum to the other two sections of the small intestine. The middle section is called the jejunum, and the final section is called the ileum. These areas of the small intestine also produce digestive juices. Millions of glands in their walls secrete about five pints of enzyme-rich juices every day.


When the food you have eaten has finally been broken down into its basic components - amino acids and simple sugars - the molecules are small enough to be absorbed into the bloodstream for transport where they are needed. The average adult absorbs about ten litres of food and liquids every day.

Processing Carbohydrates

Vegetables, fruits, and grains supply your body with fiber, protein, vitamins, minerals and carbohydrates (starches, and sugars). Carbohydrates are the easiest foods for your body to digest. Many experts believe that about 60 percent of your total calorie intake should come from carbohydrate-rich foods, such as fresh fruits, vegetables, and whole grains.

As soon as you begin chewing, the enzyme amylase begins to break down carbohydrates into glucose, the simple sugar that is used by your body for energy. If you chew something starchy long enough, it will begin to taste sweet; a direct result of the enzymes in your saliva at work. After the breakdown of carbohydrates into glucose by your small intestine, the glucose passes into your bloodstream, which carries it to other parts of your body. Any of your 75 trillion cells can use it right away for energy, while some of it is stored as glycogen in your liver and muscles until it is needed.

Processing Protein During the digestive process, proteins are broken down into their component parts called amino acids. The probiotics (friendly bacteria) such as lactobacillus are esstential for this process. Your body requires approximately twenty-two amino acids in a specific patterns to make human protein. Fourteen of these acids can be produced by an adult body. The remaining eight, called essential amino acids, must be supplied to the body daily from your diet.

To find out how many grams of complete protein you must eat every day to furnish your body with sufficient amino acids, divide your body weight by 1,000. For example, someone who weighs 70kg needs seventy grams of high-quality protein every day.

Next, multiply the total calories by 0.25 (25 percent) to determine the maximum number of calories that should come from fat: For example 1,950 total daily calories x 0.25 = 487 total calories from fat

Finally, as 1 gram of fat has 9 calories, divide the total calories by 9 to determine the total daily fat-gram allowance;

487 total calories from fat ÷ 9 calories per fat gram = 54 total grams fat daily

At first, 54 grams of fat may seem like a great deal, but consider that one tablespoon of butter (or margarine) spread on your morning kaya toast contains fourteen grams. You can see how easy it is for those fat grams to accumulate. And watch out for processed foods. They are characteristically high in both calories and fat content. If you're monitoring your cholesterol intake, limit your consumption of animal fat to 2,000 milligrams daily. This amount is generally considered safe on a low-cholesterol diet.

Vitamins and Minerals

Vitamins and minerals, so critical for healthy body functioning, ­ are absorbed unchanged from the small intestine into the bloodstream or Iymphatic ducts. Evidence shows the bioavailability of calcium, zinc, iron, manganese, copper, and phosphorus is increased in the presence of probiotics. This is due to the production of lactic acid, which allows for better absorption of minerals in the intestines.

Certain vitamins, especially the B Vitamins, are produced in the gut by the probiotic bacteria lactobacilli and bifidobacteria. The enhanced bioavailability of these vitamins is partly due to the acidification of the small and large intestines.


The large intestine is your waste disposal system. Once all the useful components of food have been absorbed, the indigestible parts are sent to the large intestine for finaI disposal. Here water and the remaining nutrients are extracted from the waste, are absorbed back into the bloodstream and recycled. The probiotics are essential here to prevent gas and bloating, and fiight bad bacteria. 

 Humans, unlike cows for instance, cannot digest cellulose, the fibrous carbohydrate present in plant foods. This dietary fiber, also known as roughage, aids in the waste removal process and helps prevent constipation. Good sources of fiber include vegetables, fruits, and whole grains. The remaining material travels on to the rectum and passes out of the body as waste.

Like the small intestine, the large intestine is also divided into three sections--the ascending colon, the transverse colon, and the descend­ ing colon. The ascending colon receives processed food from the small intestine through a connection on the right side. It then turns and ascends upward. When it almost reaches the waist, it becomes the transverse colon, which dips down under the pancreas and stomach, turns back up slightly, and then crosses over to the left side. The descending colon travels down the left side, turns inward, and extends to the midpoint of the body. where it meets the rectum and anus. It can take anywhere from eighteen to sixty-eight hours, or even longer, for food residue to pass through the entire large intestine. The large intestine is typically about 5 feet long in adults.

CONCLUSION How well you feed your cells plays a large part in determining how healthy you are and how long you will live. Think about this: by the time you are presented with a birthday cake that has seventy blazing candles, your body will have processed between 25,000 and 45,000kg of food! In the next blog entry, you will meet the friendly bacteria that live in your gastrointestinal tract and aid in the digestive process. Feeding your cells well is vitally important, but without the help of these friendly bacteria, all sorts of problems can beset the human body. Once you have read the rest of the story, you'll understand exactly why we say that your health begins in your gut!

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