The body's digestive system is like a city's power plant.  Its furnaces burn fuel and supply energy to all parts of the city.  The fuel must be the proper type or the furnaces won't function efficiently.  The power plant must also supply the heat or spark which causes the fuel to ignite.  If the fuel doesn't burn, the city will have no energy.

Our bodies also need fuel to provide the energy needed to maintain our own spark of life.  The body is built, repaired and fueled by about a half ton of food per year.

This fuel must be selected carefully to provide maximum performance, but having the right kind of fuel is not enough.  The food we eat must be digested and assimilated in order to provide the life energy our bodies require.

The digestive system supplies the spark, which initiates the burning (digestion) of our food.  If this system is not functioning properly, even the best nutrients do us little or no good.

Various secretions of the digestive system - most importantly the enzymes - provide the spark that breaks our fuel down into compounds which the body can use.

The Digestive Process

There are three major types of foodstuffs which must be broken down for complete digestion.  Theese are carbohydrates, proteins and fats.  Each day roughly two-and-one-half gallons of digested food, liquids and digestive secretions flow through the digestive tract.

The digeston of carbohydrates begins with a starch-digesting enzyme in the saliva; approximately three pints of saliva are produced each day.

Carbohydrate digestion is completed by starch and sugar digesting enzymes from the pancreas and small intestine.  All carbohydrates are broken down into simple sugars.

Proteins break into smaller fragments, influenced by hydrochloric acid and pepsin in the stomach.  Then they break further into free amino acids in the intestines by enzymes from the pancreas and intestinal wall.

Fat digestion isn't complete until it reaches the small intestine.  Bile salts from the liver and gall bladder make the fat water-soluble so that it can be carried through the bloodstream, while enzymes from the pancreas and intestinal wall break the fat into fatty acids and glycerol.

When these food particles are small enough, they pass from the small intestine to the bloodstream, where they join other nutrients to be circulated to all body cells.  About 90 percent of absorption takes place in the small intestine.