Although there are thousands of enzymes in the human body, the most significant impact on human nutritional intake is digestive enzymes. The lack of sufficient active digestive enzymes not only prevents food nutrients from being fully absorbed, but also affects the efficiency of muscle synthesis in the body. Nutrients will be absorbed by intestinal cells through different enzymes in the digestive tract, and then transported to various tissues and organs of the body.
Generally speaking, the main digestive enzymes in the human body are in the following categories:
The digestive enzyme that digests and decomposes carbohydrates is amylase, which is a digestive enzyme secreted from the pancreas to help the digestion and absorption of starch foods. Amylase can be divided into alpha amylase, beta amylase, pullulanase and glucoamylase, etc., through these enzymes, starch can be completely decomposed. In addition, the human body belongs to monogastric animals, so like other monogastric animals, the decomposition of starch is mainly done by endogenous α-amylase.
The function of protein digestive enzymes is to decompose and digest the protein ingested by people. When we eat, the stomach will begin to secrete strong protein digestive enzymes, preparing for the digestion process. In the absence of such enzymes, no amount of protein intake will have any effect, so some protein nutrition supplements on the market, such as whey protein, will add some digestive enzymes in advance. Proteases can be mainly classified into metal loexocarboxyeptidases, metal loexocarboxyeptidases, serine endoproteases, and cysteine proteases, carboxyl endoproteases, metallo endoproteases, etc. Each protease will only act on a specific peptide bond due to different amino acid residues. For example, trypsin can only hydrolyze the bonds of amino acid or arginine residues. It means that the lack of any kind of protein enzyme will lead to obstacles to nutritional intake.
Lipase, also known as pancreatic lipase or lipolytic enzyme, is an enzyme that promotes the breakdown of fat. The enzymes that can break down fat in the human body are lingual lipase, gastric lipase, and pancreatic lipase. The digestion of fat is mainly decomposed by the action of pancreatic fat. Pancreatic fat is mainly secreted by the pancreas into the duodenum. During the digestion process, the fat is broken down into glycerol and fatty acid, and then absorbed into the body by diffusion.
Since we must constantly consume dairy-derived proteins, such as whey protein, casein, etc., these protein products usually contain unremoved lactose. Therefore, for those who are lactose intolerant, drinking these protein products can easily cause diarrhea or indigestion, which is why the body lacks lactase digestive enzymes. In our intestines, the digestion of lactose mainly depends on the lactase at the top of the small intestine villi to break down lactose into the most basic monosaccharides, which are then further absorbed. When lactase is insufficient, undercomposed lactose becomes food for bacteria in the intestine. When these bacteria digest lactose, they produce gases such as hydrogen, carbon dioxide, and lactic acid, water, and short-chain fatty acids. These large amounts of extra gas, water, and acid can cause vomiting, farting, bloating, abdominal pain, diarrhea, and sour watery stools.
The function of cellulase is to decompose fiber, but before discussing fiber enzyme, one must first understand the importance of dietary fiber. The daily intake of fiber can be divided into two categories: water-soluble and water-insoluble. The water-soluble dietary fiber includes hemicellulose, pectin, and algae gum, such as vegetables, fruits, cereals, and beans. Insoluble dietary fibers include cellulosic, woody, gum, viscose, etc. For example, beans, vegetables, fruits, and rhizome foods contain insoluble dietary fibers. Dietary fiber is very important for people, because we usually have to eat a lot of food, especially protein, which is easy to form the accumulation of toxins in the body and the burden of the digestive tract. Generally speaking, dietary fiber absorbs water in the digestive tract and absorbs other residues, indigestible wastes, food additives, toxins, carcinogens, harmful substances, etc. It can stimulate the peristalsis of the intestine and expel these unhelpful wastes from the body.