“Eat slowly and chew properly!” Every child is probably familiar with their mother’s admonishing saying, but why exactly is “chewing well” so important for the body? The answer is simple: proper digestion begins in the mouth, when amylases become active.
What are amylases?
The word “amylase” comes from the Greek word amylon, meaning “starch flour.” It belongs to the hydrolases, these are enzymes that dissolve biochemical compounds by reacting with water. Amylase is an enzyme that has important functions in the metabolism of every organism – an indispensable invention of nature. Like all enzymes, amylase is a protein produced by the body’s own glands. Its discovery dates back to 1833, when the French chemist Anselme Payen discovered it in a malt solution. At that time, amylase was still called diastase; it was the first enzyme discovered.
Function, action, and tasks
In its original, undigested form, the food supplied is not usable by the body. During the digestion process, it is broken down into its smallest components, which are subsequently absorbed into the blood and thus carried into the metabolism. Digestion already begins in the mouth. Through a mechanical process called “chewing,” the food is broken down with the help of the teeth. This stimulates the flow of saliva and makes the food more slippery so that it can be carried further through the esophagus into the stomach without any problems. In the mouth, the food comes into contact with an important enzyme from the saliva called “amylase”. This is responsible for breaking down complex multiple sugars (polysaccharides) and starch. Only in this way are the nutrients broken down into smaller individual parts (in this case first maltrose, then glucose and then complex oligosaccharides) and made usable by the body. This makes the carbohydrates easier to digest. Only a fraction of the starchy nutrient is released into the blood in this way. This energy-saving method of the organism is important so that digestion functions regularly and appropriately and our food is thus converted into energy. There are four different types of amylase:
- The isoamylases: this is found only in bacteria and plants. It splits glycogen (storage form of carbohydrates) and amylopectin (natural starch).
- The γ-amylase: it splices glucose, but is found only in fungi.
- The α-amylase: hereby the amylose (starch flour) and the amylopectin is hydrolyzed. It can act as the only enzyme inside a starch molecule. For this reason, it is an endoenzyme.
- The β-amylase: this enzyme is an exoenzyme, but has the same property as α-amylase. However, it cleaves only one maltose molecule at a time in sequence from the chain end. So the more chain ends created by the α-amylase, the better the β-amylase can act.
As a small molecule, α-amylase is excreted by the kidneys through the urine.Thus, its measurement in blood serum and urine is possible.
Formation, occurrence, properties and optimal values.
The α-amylase consists of five so-called “isoforms.” Two of them are formed in the acinar cells of the pancreas (lat. pancreas) and are called pancreatic amylase. From here they are released directly into the intestine. The other three isoforms are produced in the exocrine glands of the oral cavity. There are three major salivary glands there:
- The parotid gland (parotid gland).
- The sublingual gland (sublingual gland)
- And the submandibular gland (submaxillary salivary gland).
When chewing food, they become active and secrete saliva laced with the enzyme. As mentioned above, you can measure amylase levels in the blood and urine. Urinalysis requires the patient’s collected urine, which must be collected over a 24-hour period. Since not every analysis device works equally well, the information on the optimal values varies. However, as a general rule, amylase values measured in blood serum should be between 31-107 units per liter (U/I) in an adult human as best as possible, while those measured in spontaneous urine should be approximately up to 460 U/I and those in collected urine should be approximately up to 270 U/I. As a rule, amylase levels that are too low are not of disease value.
Diseases and disorders
An elevated α-amylase level may be an indication of a pathologic process, but it is not proof. First, it may be due to an acute inflammation of the parotid gland called parotitis. This is triggered by viruses and bacteria and is accompanied by severe pain, a clearly visible swelling and intermittent fever. It can be caused, among other things, by frequent vomiting (such as in bulimia). Most often, however, the childhood disease mumps is responsible for this inflammation. Also at risk are people with an insufficient fluid intake or reduced chewing activity. As a result, saliva production is throttled, and invading bacteria cannot now be flushed out properly. Similarly, there are certain groups of medications that inhibit saliva production, such as diuretics or antidepressants. Poor oral hygiene, a slightly inflamed oral mucosa and malnutrition also promote bacterial formation. An increased concentration of α-amylase in the blood count can also be a sign of pancreatitis. The most common cause is biliary tract disease.
