Most often recognized symptoms due to enzyme deficiency is lack or low activity of the gastrointestinal enzyme lactase, which splits the non-absorbable milk sugar or lactose into the easily absorbable monosugars. In the absence of this enzyme, the milk sugar is transported unchanged to the large intestine where it is fermented by the bacteria. Excessive fermentation will manifest with gas and diarrhea - a typical complaint among people with lactose intolerance. In general, there are also more serious and less recognized population, conditions due to enzyme deficiencies.
Pancreas is a digestive organ that manufactures several enzymes which include the major three groups of enzymes, i.e. amylases, lipases and proteases. These enzymes are released everyday by healthy pancreas to the small intestine to literally make the food useful to us. In a disease condition of pancreas, due to, for example, an excessive use of alcohol the production of pancreatic enzymes is severely diminished. That results in poorly digested food which shows in an undigested form in the stool. This way the undigested fats will show in stool, which technically is known as steathorrea.
Another condition that can impair enzymes production is gastritis, or inflammation of the lining of stomach. Stomach mucosa is built of specialized cells that manufacture gastric acid, mucus and the protein digesting enzyme pepsin which helps in the breakdown of proteins. Deficiency of pepsin will eventually manifest by poor absorption of proteins. In general any inflammatory process in the gastrointestinal tract will interfere with the digestive enzyme production by disabling the specialized enzyme production cells.
In fact, it may be said that lack of digestive enzymes increases the inflammatory process in the gut, which further shuts down the enzyme production. On the other hand, restored presence of the digestive enzymes can help in healing action.
The markedly diminished activity of enzymes in the digestive tract may initially be manifested by a gastrointestinal discomfort such as gas, bloating, nausea, intestinal cramps, diarrhea and also constipation.
Undigested nutrients cannot cross the barrier between gut and blood vessels and thus are not bioavailable to the metabolic processes in specialized tissues and organs of the body.
A chronic deficiency of digestive enzymes may result in progressive depletion of nutrients and paradoxically increase in body weight due to accumulation of fat. The too often imperceptible process of nutrient deficiency eventually may lead to a full-blown pathology, including chronic degenerative and inflammatory disease and the neoplastic disease.