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Protein is primitive substance of human nutrition. Protein comes from
the Greek "prota", meaning "of primary importance" and were first
described and named by Jöns Jakob Berzelius in 1838. Proteins are large
organic compounds made of amino acids arrange in a linear chain and
joined together between the carboxyl atom of amino acid and the amine
nitrogen. Proteins are essential parts of all living organisms and
participate in every process within cell.
Amino acids are the basic structural building units of protein. Most
amino acids occur in two possible optical isomers, called D and L. The
L-amino acids represent the vast majority of amino acids found in
proteins. D-amino acids are found in some proteins produced by exotic
sea-dwelling organisms, such as cone snails. There are twenty standard
amino acids which are encoded by the standard genetic code. Some of the
20 standard proteinogenic amino acids are called essential amino acids
because human body cannot synthesize them from the other compounds
through chemical reaction. One way to get them is obtained from food.
There are 10 essential amino acids.
- Isoleucine: food sources of isoleucine are eggs, chicken, pork,
mutton, pulses, soy beans, cottage chess, milk, piyal seeds, cashew
nuts, and cereal grains.
- Leucine: The most common amino acid found in proteins. It also plays
a part in maintaining muscles by equalizing synthesis and breakdown
proteins. Food sources of leucine are whole grains and milk product,
egg, pork, beef, chicken, pulses, soy beans, leafy vegetables
- Lysine: food sources of lysine are fish, soy beans
- Methionine: Sulfur-containing proteinogenic amino acid. Food sources
of methionine are spinach, green peas, garlic, cheeses, corn, brazil
nuts, pistachios, cashew nuts, kidney beans, chicken, beef, fish,
vegetables, nuts, legumes
- Phenylalanine: Food sources of phenylalanine are dairy food (curd,
milk, cottage cheese), avocados, pulses and legumes, nuts, piyal seeds,
leafy vegetables, whole grains, poultry, fish and sea foods.
- Threonine: Food sources of threonine are cottage cheese, poultry, fish, meat, lentils, and sesame seeds.
- Tryptophan: A precursor for serotonin, melatonin and niacin. Food
sources of tryptophan are oats, bananas, dried dates, milk, yogurt,
cottage cheese, meat, fish, poultry, sesame, chickpeas, peanuts.
- Valine: Food sources of valine are cottage cheese, fish, poultry, peanuts, sesame seeds, lentils.
- Arginine (essential only in certain cases): A semiessential or
conditionally essential amino acid , depending on the developmental
stage and health status of the individuals. Food sources of arginine
are chocolate, wheat germ and flour, buckwheat, granola, oatmeal, dairy
products, beef, pork, coconut, pecans, cashews, walnuts, almonds,
Brazil nuts, hazel nuts, peanuts, pumpkin seeds, sesame seeds,
sunflower seeds, poultry, pheasant, quail, seafood, soy beans.
- Histidine (essential only in certain cases): Food sources of
histidine are grapes, meat, poultry, milk products, root vegetables,
green vegetables.
Proteins are necessary for body builders because main point of body
building is lifting weight to rip muscles but don’t make it injure.
Proteins which body builders consume go to renovate muscles from
ripping; remaining proteins go to increase muscles size. A sufficient
protein for body builder should be 1 – 1.5 grams per 1 pound of body
weight per day. But don’t be confuse protein weight and food weight,
because in one kind of food there are many type of nutrition such as
fat, carbohydrate, fiber and minerals. A piece of beef separable lean
and fat, trimmed to 0 inch fat weight 100 grams contains with protein
30.5 grams, carbohydrate 0 gram, fat 9.4 grams and has 215 calories. A
piece of chicken meat and skin weight 100 grams contains with protein
22 grams, carbohydrate 10.3 grams, fat 21.9 grams and has 331 calories.
Protein that human consume will transform to amino acids. If human body
cannot absorb all of amino acids, amino acids cannot hold up in the
body. Amino acids will release to urine. Body builders who must consume
more protein than another people should calculate their sufficient
protein for getting high useful protein in each day. |