The Stomach

The food passes from the esophagus into the stomach through an opening called the cardiac orifice. As soon as food enters the stomach, a hormone called gastrin is released into the bloodstream.

This hormone is carried to the gastric glands in the stomach, which causes them to secrete digestive juices. These gastric juices help in the chemical digestion of the food, while the rhythmic contractions of the stomach contribute to the mechanical process of digestion. These juices contain primarily hydrochloric acid (HCl) and digestive enzymes.

This hydrochloric acid makes the stomach a very acid environment with a pH factor between 1.5 and 3.0 This acid environment serves two, functions: 1) it acts as a denaturant in digestion of proteins; and 2) it kills small parasites that are often found in all foods.

There are three primary enzymes present in the gastric juices…

The first is pepsin, which aids in the hydrolysis of proteins. The pepsin enzyme begins breaking down complex proteins into their simpler forms. It does not actually split the proteins into amino acids (the end-product of protein digestion), but it prepares them for that process which is suppose to happen in the intestines. The pepsin enzyme works best in a fairly acid environment

The second enzyme is called lipase. This aids in the hydrolysis of fats. Lipase digests fats by aiding their breakdown into glycerol and fatty acids.

The third enzyme, found only in the gastric juices of infants, is called rennin. Its primary function is the hydrolysis of milk proteins. Adults do not have the rennin enzyme in sufficient quantity to digest milk products. Consequently, the only time milk should be used in the diet is during infancy and young childhood. Even at these times, the only suitable milk is that from the lactating mother. Milk from cows, goats, etc. is not of the same composition as is mother's milk.

Gastric juice along with all these three enzymes are mixed into the food by the mechanical actions of the stomach. The stomach contracts in waves at the rate of three per minute.

The gastric juices mixed in by the contracting and relaxing stomach are initially stimulated by the thought, sight, smell and taste of the food. This occurs before any food has actually entered the stomach. These juices are sometimes called the "appetite juices", and they may be suppressed if the food appears unappetizing, smells bad, or is eaten in an unpleasant environment.

Even the emotions can have an impact on the secretions and appetite and in the presence of intense pain, fear, depression etc, gastric juices may almost suppressed.

FACT - The stomach empties at the slow rate of about 3/100 ounce for each peristaltic wave. Making it three waves per minute, it can take up to five hours for two pounds of food to leave the stomach.

The emptying time of the stomach also varies with the type of food present. Water and liquids leave the stomach most rapidly. Fats are getting emptied very long as they are heavy to digest. Carbohydrates empty more quickly than proteins; proteins, in turn, leave the stomach more quickly than fats.

Within five minutes after fat enters the stomach, a hormone called enterogastrone enters the bloodstream and travels to the stomach; this hormone inhibits the motion of the stomach and makes it to empty at a much slower rate.

Since different foods require different sets of environments in the stomach to digest properly, it is reasonable to assume that if these foods are put into the stomach at the same time, difficulties could occur. That is exactly what happens.

If different foods are to be put into the stomach at the same meal, they should at least be of the same type that requires the same set of digestive conditions. Ideally, of course, only one food should be eaten at a meal to insure optimum digestion.

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