It must be remembered that all living cells contain protein. It would be suffice to say that protein is a substance necessary to life.
It is strange to note that the word “protein” is derived from a Greek word meaning thereby “first” , because proteins are considered to be the most essential part of living matter.
Further, each kind of cell has its own protein. In fact, proteins are made up of combinations of substance called “amino acids”.
The form of amino acids can be more than twenty-one different types. In addition to carbon, hydrogen and oxygen, each amino acid group contains the chemical element nitrogen. The different types of amino acids can combine in different ways to form different proteins, and there are thousands of different proteins. For example, we are well aware that meat contains protein, but had it ever known to you that it is made up of at least twelve to fifteen different proteins.
The necessity of the foods that are considered essential for our existence merely all depends on the proteins they contain. These include milk, meat, fish, eggs, peas, beans, peanuts and certain grains. They are essential for a human because they provide the amino acids which cannot automatically be formed in body itself. Humans must get amino acids from the protein in the food he eats. Actually, these “essential amino acids”, are absolutely essential without which the life of a person will always remain in question, and his survival is almost impossible. Certain amounts of different kinds of amino acid are essential so that the body tissues can use what they need.
Plant protein such as those in beans, peas and cereals lack in essential amino acids. But, their value increases all the more as fare as diet is concerned when they are combined with some of the animal proteins.
Humans cannot store amino acids in their body for using them in future. It means that the different kinds of amino acids should be eaten at the same meal so that the amino acids they provide can be very well used together to form new body tissue. Higher percentage of amounts of different kinds of protein foods should be eaten at each meal.
Now you are sure of getting the required quantity of different kinds of essential amino acids to meet the body’s protein needs for our existence.