The gastrointestinal system, a complex network of organs and glands which extracts nutrients and water from the food that we eat so that they can be used by the body, processes the food in six phases. First, it mentally prepares the stomach for the meal that we are about to eat. Then, it takes food into the body, followed by moving that food through the GI tract. Next, it breaks down the food with both mechanical and chemical processes and then absorbs the digestive food into the vascular and lymphatic systems for distribution to the cells. Finally, the indigestible substances and waste products are eliminated from the body. Digestion itself is divided into two categories, those being mechanical and chemical. Mechanical digestion is the physical movement that assists chemical digestion. After the initial breakdown by chewing, food is churned by the smooth muscles of the stomach and small intestine, allowing it to mix with the enzymes that start the chemical reactions. Chemical digestion, on the other hand, is a series of chemical reactions that break down large carbohydrate, lipid, and protein molecules into smaller molecules that can enter blood vessels. In order for optimal digestion to occur, all of these processes must work together. If any part of the system under or over-performs, physical problems will most likely occur.

Enzymes are extremely important to digestion because without them digestion could not take place and the food we eat could not be absorbed into our bodies to be utilized. Enzymes, which are complex proteins that are produced by living cells and can be found in digestive juices, start chemical reactions in the body. They act on food by breaking it down into simpler components that can be used by the body for energy. If digestive enzymes don't work adequately, inadequate digestion will result which is thought to be a significant cause of food allergies. When food is not digested completely it can initiate allergic reactions in the body, causing inflammation and immune sensitivity and lead to chronic inflammatory conditions and certain types of arthritis.

There are many enzymes that are part of the digestion process. However, there are three main enzymes that are involved in digestion. These are amylase, protease, and lipase. Other enzymes, including sucrase, lactase, and maltase are very important for secondary function in digestion. Amylase, which breaks down carbohydrates, can be found in saliva and pancreatic secretions. It initiates digestion of dietary starches and breaks down starch into several simpler molecules. Disaccharides including lactose, maltose, and sucrose, are broken down into simple sugars by lactase, maltase, and sucrase. These simple sugars can be absorbed through the small intestine to help with energy production. Proteases, which break down protein, cause protein digestion to begin in the stomach. The stomach's acidic environment activates the protease pepsin, which is deactivated in the alkaline environment of the intestine. Proteins are further broken down by pancreatic enzymes into amino acids in the intestine. Lipases break down fat into essential fatty acids. Fat digestion speeds up in the second part of the small intestine with the help of the pancreatic lipases. These lipase enzymes are responsible for the absorption of vitamins A, D, E, and K.

Animal enzymes, especially those that are derived from pig enzymes are very similar to human digestive enzymes. Animal enzymes are much more sensitive to pH extremes; therefore many animal enzyme formulas sold as dietary supplements contain bicarbonates to protect the enzymes from stomach acid. Plant derived enzymes, on the other hand; come from fungal and botanical sources. They are able to survive a broad range of pH differences and provide a larger range of activity in the gastrointestinal tract. Plant enzymes are often preferred by those who wish to avoid animal-derived products.

Along with these, there are many other dietary supplements that are effective in supporting digestive health, specifically probiotic supplements, which offer numerous health benefits. Probiotics are non-toxic, live bacteria that are necessary for life and do not cause disease. The most commonly studied probiotics are those from the Lactobacillus and Bifidobacterium group. Because these two probiotic groups have the ability to break down lactose, they are known as lactic acid bacteria. These probiotics can be found in many foods and dietary supplements. In our intestines we have colonies of bacteria called microflora, which is associated with good health when they are normal. However, changes in intestinal health are often associated with a weakened immune function and an imbalance in the natural microflora is often linked with various diseases such as yeast infections and colon cancer. By orally ingesting probiotic bacteria, we help to support the composition and metabolic activities of the microflora found in the large intestine. These microflora help the digestive process through fermentation, protection against disease-causing bacteria, and stimulation of certain immune system components. Probiotic bacteria have also demonstrated anti-cancer properties in many studies. Results have shown that people taking L. acidophilus fermented milk have a much larger number of intestinal Lactobacilli, which in turn decreases the risk factors associated with colon cancer.

Lactose is an important sugar that is converted to lactic acid by lactic acid bacteria. Many people have lactose intolerance as a result of genetics, gastrointestinal disease, or a decline in the amount of intestinal lactase levels that are associated with aging. Lactose intolerance is caused by an inability to digest lactose because of a failure of small intestine cells to produce lactase (the enzyme needed to digest lactose). Those who are deficient in lactase accumulate non-absorbed lactose in the GI tract, drawing water and electrolytes into the gut. This leads to bloating, cramping, diarrhea, and malabsorption of nutrients. Lactic acid bacteria support the breakdown of lactose by enhancing the activity of lactase, therefore improving digestion and tolerance. Although probiotic bacteria usually survive passage through the stomach, they do not permanently colonize in the body. Therefore, to ensure optimal support of the digestive system, these probiotic bacteria need to be replenished. To do so, they should be ingested regularly in order for their health-promoting effects to continue. Digestive enzymes and probiotics can be found at your friendly online vitamin store.