Essential amino acids refer to amino acids that cannot be synthesized by the human body (or other vertebrates) or whose synthesis rate cannot meet the needs of the human body, but must be provided by food. For adults, there are eight essential amino acids, namely lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, and valine. In addition, histidine is necessary for infants.
Essential amino acids are important raw materials for protein synthesis in the body, and provide the material basis for promoting growth, normal metabolism, and maintaining life. Essential amino acids are very important in human life activities. If the human body lacks any one of the essential amino acids, it will lead to abnormal physiological functions, affect the normal progress of life metabolism, and finally lead to the occurrence of various diseases.
Essential amino acids in the human body
As the main raw material for protein synthesis, lysine is involved in the synthesis of important proteins in the human body. In addition, lysine participates in the regulation of metabolic balance, which can improve the secretion of gastric juice, increase appetite, and promote human growth and development. At the same time, lysine can also enhance human immune function, improve calcium absorption, and accelerate bone growth. L-lysine has physiological activity, D-lysine has no physiological activity. The lack of lysine will cause the lack of protein, affect the growth and development of the human body, and even lead to the occurrence of diseases. The main food sources of lysine: milk, eggs, meat, beans and other protein-rich foods.
Tryptophan can participate in the renewal of plasma proteins, promote the synthesis of serotonin and melatonin, and promote sleep. Clinically, tryptophan can be used to treat bronchial asthma. Tryptophan can also be anti-allergic, and has a good effect on seasonal rhinitis, acute and chronic allergic conjunctivitis, allergic eczema and intestinal allergic reactions caused by food. Tryptophan can be converted into many physiologically important active substances in the body, such as 5-hydroxytryptophan and the precursor of niacin. 5-Hydroxytryptophan is an important neurotransmitter in the human body. The main food sources of tryptophan: milk, meat, brown rice, etc.
Phenylalanine is involved in the body's glucose metabolism and fat metabolism, which can reduce hunger, eliminate depression, improve memory and improve thinking agility. The main food sources of phenylalanine are peanuts, almonds, bread, etc.
Methionine is the only sulfur-containing amino acid among the essential amino acids. Methionine is involved in the composition of hemoglobin, tissue and serum, and has the function of promoting metabolism. Methionine can protect liver and heart muscle, adjust blood pressure, prevent fatty liver, cardiovascular disease and kidney disease. The methyl group carried by methionine can detoxify toxic substances or drugs by methylation. The main food sources of methionine: yogurt, meat, beans, onions, garlic, etc.
Threonine can maintain protein balance and assist in protein absorption and utilization. At the same time, threonine can relieve fatigue and strengthen the immune system. The main food sources of threonine: animal liver, meat, etc.
Isoleucine is an amino acid necessary for the formation of hemoglobin, which can regulate the level of sugar and energy metabolism. In addition, isoleucine can help improve physical performance and repair muscle tissue. Leucine, isoleucine and valine, these three amino acids have the same branched side chain in structure, so they are called branched chain amino acids. Main food sources of isoleucine: milk, eggs, meat, wheat, corn, soybeans, various kernels, etc.
Leucine acts to balance isoleucine, which regulates blood sugar levels, promotes muscle recovery, reduces sensitivity to pain, and promotes sleep. The main food sources of leucine: milk, eggs, meat, wheat, corn, soybeans, various kernels, etc.
Valine acts on the corpus luteum, mammary gland and ovary to repair tissue, speed up wound healing, treat liver failure, increase blood sugar levels and increase growth hormone. The main food sources of valine: milk, sesame, soybean, almond, etc.
Histidine is an essential amino acid during the growth and development of infants and young children, which can promote normal body development, body growth and tissue repair. The main food sources of histidine: bananas, grapes, meat, poultry, milk and dairy products.