- Every living organism, from the largest animal to the tiniest microbe, is composed of protein. And in its various forms, protein participates in the vital chemical processes that sustain life.
- Like every living organism, human body uses 20 different amino acids in different combinations to make all proteins. Our genes dictate in which order the amino acids must be chained. In addition to these 20 amino acids body makes derivatives of these amino acids to use in number of other processes, such as, producing carnitine from lysine and methionine for the fat metabolism, or tryptophan conversion to serotonin and melatonin, or phenylalanine to tyrosine and further to adrenalin.
- A well-known fact is that 65% of human body is water. If we consider in the rest of the percentage 20% is proteins, and all of the proteins are made from amino acids, it is rather significant amount. This alone makes their role in our diet absolutely indispensible.
- One gene can encode at least one protein, so to our current knowledge there are about 21.000 protein-encoding genes. But the number of different proteins in humans can be from 250.000 up to 1 million. To ensure the production of these proteins human body needs all of these 20 amino acids and especially those essential 9 amino acids, which can be only obtained from food.
- Low level of any of the essential amino acids will be the limiting step for a particular protein production.
How do cells work?
Cells are doing their functions by producing structural or functional proteins. During this process RNA uses only 20 different amino acids to build up a protein.
These proteins function mainly in two different ways:
- Structural proteins such as collagen and keratin which are main structure of muscles, skin, hair, bone, tendons etc.
- Functional proteins such as enzymes, hormones, antibodies
All living functions are controlled by proteins which are made from amino acids
Amino Acids: Building blocks of life
Essential Amino Acids
Every day you have obtain from foods. Your body cannot synthesis these.
These amino acids can be synthesed in your body even you dont obtain enaough from foods.
- Aspartic Acid
- Glutamic Acid
Their synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress
Since genes controlled all functions by producing proteins from amino acids, and amino acids are obtained from foods,; the most important nutrient must be amino acids.
Proteins are made up of 20 kinds of amino acids. Of these 20 kinds, 9 must be taken from food since they are not synthesized in the body. Therefore, they are called "essential amino acids". It is necessary to consume these "essential amino acids" from food in well-balanced, appropriate amounts.
As well as essential amino acids animals and human do have dietary requirements of non essential amino acids to fulfill their genetic potential for maximum growth, reproduction, lactation, and production performance, as well as optimal health and wellbeing . Rates of NEAA synthesis depend on the availability of EAAs and glucose, as well as species, breed, age, physiologic status, and disease state.
The proteins that form the human body are not obtained directly from the diet. Rather, the dietary protein is broken into its constituent amino acids that the body uses to build the specific proteins it needs.
Therefore, the main nutrients are amino acids, not proteins.
All Amino Acids Are Obtained From The Foods We Eat
By digesting the nutrients, the chain structure of the protein content breaks down and the amino acids are released. The amino acids in free form are readily absorbed from the intestines.