3.2.1.1 Protein GapFill

Proteins are organic macromolecules built from  peptidescouscousamino acidsadipose tissue, bound together into long chains.There are about 20 different amino acids which can combine to make a molecule of protein. Some of the amino acids can be built by the body from scratch – for this reason they are called 'dispensable'. If an amino acid cannot be built by the body from scratch, it is called  an insolublea misoa high biological valuean essential amino acid and has to be provided as a part of a healthy diet.

There are  ninetwoeleventwenty essential amino acids and if they are all present in a molecule of protein, such protein is called a complete protein and has a  incomplete valueinsufficient valuehigh energy valuehigh biological value. If one or more of the amino acids is missing, the protein is considered  an unstablea stablea solida low biological value protein.

Protein  complementingcorrelationcoagulationcomplementation allows us to combine two or more sources of low biological value proteins to make a   fattywholetextured vegetableadequate protein. An example of this is  cheese on toasthot dogspaghetti bolognesebeans on toast. Complete proteins occur mostly in  nutsfruits and vegetablesanimal-derived foodsplant foods, but also in  breadgherkinsquinoacouscous and  green peasolive oilsoytomatoes.

Proteins are necessary to build  lardadipose tissueall cells in the bodyunsaturated fat , enzymes and hormones. They can also be used as a  primaryinsolublesecondaryfree source of energy – this means that they are only used as a source of energy if other sources (carbohydrates and fats) are not available.
If a person eats too little protein, he or she may develop a disease called  kwashiorkorkidney stonesscurvynight blindness. Too much protein can also be harmful for the body, causing harm to the liver and the kidneys.