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Digestive Enzymes for Health

Updated on November 13, 2012

The Digestive System

Function of Digestive Enzymes

Enzymes are natural substances (all of them so far discovered are proteins) that speed up chemical reactions necessary for the metabolism. They are catalysts, which is a chemical term for any substance that speeds up a chemical reaction; but enzymes are many times better at it than any such substance used for the purpose in non-biological chemistry.

Digestive enzymes are enzymes which carry out the process of digestion, but what is not quite so obvious is that there are several digestive enzymes, all of which have different functions. Lack of any one of them will make it difficult or impossible to digest that particular component of the food.

To explain the benefits of digestive enzyme supplements, it might be useful to go through the process of digestion and explain what the body’s various normal digestive enzymes do.

The digestive process starts in the mouth. Chewing food breaks down solid food into smaller pieces, important because smaller pieces are easier for the rest of the digestive system to work on. In addition, saliva contains a starch-digesting enzyme called ptyalin or salivary amylase, which starts the digestion of starch in particular. This can be interestingly demonstrated by thoroughly chewing some starchy food such as bread; after a while it starts tasting sweet, and this is because of glucose being released.

The next step is in the stomach. In the stomach, large amounts of strong acid (hydrochloric acid) are released along with pepsin. The acid has two main functions; killing pathogens and changing the shape of protein molecules in the food to make it easier for the pepsin to work on them. Pepsin’s function is to chop protein molecules into fragments for enzymes further along to work on.

This partial digestion has another effect; that of liquefying the food, which makes it easier for the rest of the digestive system to do its work.

After a while, when the food is liquid, it is expelled from the stomach into the duodenum - the first foot or so of the small intestine - where the liquid is mixed with bile and pancreatic juice. From the digestion point of view, the main function of bile is to act as a detergent, breaking up the fat in food into microscopically small globules so that fat-digesting enzymes (lipases) can work on the fat. Pancreatic juice contains a cocktail of enzymes; proteases (which digest proteins and include trypsin and chymotrypsin), amylases that digest starch, and lipases that digest fats. Pancreatic juice also contains various transport chemicals such as picolinic acid, which are there to help absorb minerals and vitamins.

In infants and small children, and in a minority of older children and adults, the pancreas also produces lactase, whose function is to break down lactose from milk.

The food, digestive secretions and bile then go further, into the ileum which comprises most of the small intestine and is lined with villi - fingerlike projections that massively increase the effective area of the intestinal wall - and most of the breakdown products of the food are absorbed there. Also in the small intestine, there is some help from our internal bacteria; in particular, in adults most of the work of digesting lactose is done by these bugs.

Finally (in humans) the gut contents pass into the large intestine. The main function of this organ is to reabsorb water and salts; humans produce around 50 litres of digestive juices per day, of which less than one litre is actually lost to the outside world.

As can probably be seen from this account, the process of digestion is a highly complex one with many possible points of failure. Any or all of the salivary glands, stomach lining, liver and pancreas might be either deficient in production of their various secretions or the ducts leading into the digestive system from these various glands may be partially or even completely blocked. There may be deficiencies in the population of the “friendly” bacteria, leading to incomplete digestion and inflammation of the lining of various parts of the digestive tract, and also possibly to the production of large amounts of toxic metabolic byproducts of pathogenic bacteria.

This can in turn lead to various health problems such as rheumatoid arthritis and acne rosacea, which at first glance don’t seem to have anything to do with the digestion.

Of course, disturbances in the digestion can lead to more obvious symptoms such as flatulence, diarrhoea or constipation (or both alternately) or heartburn.

Because various problems can arise with the digestive system, many different problems can be helped by supplementing with an external supply of digestive enzymes. Individual digestive enzymes can be used, but far more popular are supplements of hydrochloric acid (in the form of betaine HCl) and a mixture of the other digestive enzymes. The latter also sometimes contains bile extract, usually derived from cattle, but any product containing pancreatic or bile extract is unsuitable for vegetarians.

Digestive enzyme supplements entirely derived from various fungi are also often used, and these are suitable for vegetarians and vegans.

Typically, these products are used only with substantial meals. A small snack will probably not warrant such supplements.


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