Whenever food enters your mouth and touches the taste buds located on the surface of your tongue, your salivary glands begin secreting saliva. Saliva is needed to lubricate the food and to predigest cooked starches. At the same time, your pancreas and small intestine receive instructions to prepare for the release of the appropriate kinds and amounts of digestive enzymes and minerals necessary to help break down the food into the smallest nutrient components.

  The first and most common cause of digestive trouble is swallowing food too quickly. This eating habit indicates anxiety, impatience and nervousness. Eating too quickly reduces saliva production in the mouth cavity, which is a major cause of tooth decay. One of the functions of saliva is to keep the mouth and teeth protected against harmful substances and irritating microbes.

  There are other reasons why masticating food properly is so essential for our wellbeing. According to fascinating research conducted at the Gifu University in Japan, chewing actually improves memory by reducing the release of stress hormones. Magnetic resonance imaging (MRI) has demonstrated that the hippocampus, which helps control blood levels of stress hormones, is stimulated by the act of chewing. As a result, the simple act of chewing properly lowers both stress and stress hormones. So chewing your food well can actually reduce anxiety levels.

  The Japanese researchers also found that when teeth were missing or in a state of disrepair, people tended to chew less. Subsequently, this led to increased stress hormone levels. The conclusion from this study is that good dental health and the ability to chew properly appear to be important factors in preserving our memory as we age and in protecting ourselves against the harmful effects of stress.

   After passing through the esophagus, the food enters the stomach. If the food contains carbohydrates (complex sugars and starches as found in vegetables and grains), the salivary enzymes continue to digest these foods for about an hour before the stomach begins to secrete its gastric juices. If the food is swallowed too quickly, these foods remain mostly undigested and begin to ferment.

  Gastric juice is composed of hydrochloric acid, enzymes, mineral salts, mucus and water. The action of the acid kills many of the harmful microbes and parasites that are naturally present in fresh produce, meat, fish, dairy products and other foods. The hydrochloric acid also breaks down some of the harmful substances that may accompany the food, such as certain food additives or chemicals. Special enzymes begin to act upon proteins that may be present in the food. Once saturated with enough acid, the food is forced in small jets into the duodenum.

  The duodenum is a hollow jointed tube connecting the stomach to the jejunum, which is the central of the three divisions of the small intestine. It represents the first and shortest part of the small intestine, and it is where most chemical digestion takes place. It is called the cap because on an x-ray it looks a bit like a cap. Thereafter, the duodenum makes a C-turn going from the right to the left side of the abdomen. Bile from the liver and secretions from the pancreas come through the ampulla of Vater to mix with food in the duodenum. The pancreatic juices contain digestive enzymes, minerals and water to help break down starches further. The bile, which is forced into the duodenum via the common bile duct, aids in the digestion of fats and proteins. The duodenum participates in this very important part of the digestive process by releasing specific hormones and digestive juices. Ayurveda calls the entire activity in this section of the digestive system AGNI, or ‘digestive fire’. AGNI ‘cooks’ the food further in order to make its nutrients available for the cells and tissues at a later stage.

The small intestine has a total length of approximately 6 meters (18 feet). It is responsible for the absorption of nutrients, salt and water. On the average, approximately 9 liters (9.5 quarts) of fluid enter the jejunum (upper part of the small intestine) each day, a major portion of which is composed of digestive juices.  The small intestine absorbs approximately 7 liters (7.4 quarts), leaving only 1.5 to 2 liters to move on to the large intestine. The absorptive function of the small intestine is brought about by an intricate array of cells within its lining (intestinal folds and villi) that absorb and secrete salts and nutrients as well as water in order to maintain normal salt and water balance within the body. In a healthy person, the absorptive function is so efficient that with a natural, balanced diet, over 95 percent of ingested carbohydrates and proteins are absorbed.  

  Specific sections of the small intestine perform specific functions. For example, the duodenum plays an important role in coordinating how the stomach empties and at what rate bile needs to be secreted into the intestine to optimize the digestive process. The duodenum is also a major site for the absorption of iron. The jejunum is a major site for the absorption of the vitamin, folic acid, while the end of the ileum (lower part of the intestine) is the most important site for the absorption of vitamin B12 and bile salts. The blood takes up all the nutrients and moves them to the liver for further processing.

   The ingested food can be broken down into its basic nutrient components and made available for the complex metabolic processes in the body only when AGNI, the digestive fire, is strong. AGNI is fueled by bile, without which none of the other digestive juices would be sufficiently effective to break down food into its nutrient components. Bile is alkaline. When food that is saturated with hydrochloric acid enters the small intestine, it first needs to be mixed with bile before digestive enzymes can act on the food. An intestinal pH-value of high acidity would block enzyme secretion and become a major stumbling block for the proper digestion of food. Furthermore, in order for them to become activated, pancreatic enzymes must combine with bile before passing through the ampulla of Vater. To make this possible, the common bile duct and the pancreatic duct combine to form one short duct before joining the duodenum. As long as bile secretion from the liver’s bile ducts and the gallbladder remain unimpeded by gallstones, good digestion is almost guaranteed, provided that the ingested food is fresh and wholesome.

  The combination of nutritious food and strong AGNI forms the ideal partnership to help the body make sufficient amounts of amino acids, fatty acids, minerals, vitamins, glucose, fructose, trace elements and other vital substances available to all its parts. This, in turn, produces healthy blood, vital tissues and a youthful body. The quality of the blood and the tissues of the body, including those that make up the skin, mostly reflect the condition of the liver and the small intestine.