Answer
The nutritional value of a protein depends on its amino acid composition. There are 29 amino acids in proteins, some of these the body can synthesize and some must be obtained from dietary sources because the body cannot make them. The eight amino acids are leucine, isoleucine, lysine, valine, threonine, methionine, tryptophan, and phenylalanine.
The synthesis of proteins by cells require the availability of all the amino acids for protein to be made. If even one amino acid is unavailable the synthesis cannot be successful. Dietary proteins that supply all the amino acids necessary for successful protein synthesis are called complete proteins. In contrast incomplete proteins are missing one or more of the amino acids that the body cannot make
Net utilization describes the percentage of proteins in a protein source that can be used by the body. Animal proteins and plant proteins are different in this regard. Generally, only about 40-70% of proteins from a plant source are useful to the body, but 70-90% of animal proteins are utilizable by the body. For some foods it takes three times as much plant foods to supply the available protein supplied by a given weight of animal food.
Plant foods are more poorly utilized by the body because may plant proteins are incomplete, that is they lack one or more of the essential amino acids. But more proteins from animal sources are complete proteins. Notwithstanding plant foods are useful and have many functions necessary for good health; furthermore, plant substances can be combine so that one plant food rich in one or more essential amino acid can complement missing amino acids in another plant food substance, Some examples of complementary amino acid combinatuionare grains and legumes, green leafyvegetables and grains and legumes, nuts and seeds.
Work Step by Step
There are personal and societal advantages to reducing the intake of animal protein and increasing the consumption of proteins from plant sources. Some of these include the following; plant foods provide more fiber than animal foods-- fiber is important for reducing fat absorption, and facilitation waste evacuation; plant foods also supply more vitamins, minerals, and trace elements--- like chromium and selenium; plant foods have less saturated fats than animal foods, and they have no cholesterol. However, some oils like palm oil and coconut oil must be consumed with care. in addition, and both plant and animal food substances that are not organically produced may contain traces of pesticides. Finally, it is true that the production of animal foods involves the utilization of more global resources, and produces more solid, liquid and gaseous wastes.
