Protein: The Building Block of the Body
With all the rampant misinformation that has been presented--from diet books to talk shows, there is much confusion regarding "protein" in general. Protein
s are the building blocks of our body, and they are one of the major macronutrients essential to our functioning and survival (the others are: fat and carbohydrates; vitamins, minerals and water). In this short article, I hope to provide information about protein: what it is, why it is so important, what it does, and why we need it.
s are the building blocks of our body, and they are one of the major macronutrients essential to our functioning and survival (the others are: fat and carbohydrates; vitamins, minerals and water). In this short article, I hope to provide information about protein: what it is, why it is so important, what it does, and why we need it.What is its function?
The main job of protein is building, maintaining, and repairing tissue; synthesizing (creating) hormones, enzymes, neurotransmitters; carrying out most metabolic and physiological functions, and providing us with energy. Getting enough protein is vital to our bodies for repair and recovery of all functions. In fact, we are made of protein-- our hair, ligaments, nails, muscles, organs, and every part of our body are made of protein and depend on it to function. Without protein, we could not grow!
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[1] Protein amino acid chain. http://wikids.wikispaces.com/file/list?o=80
[2] The primary structure of a protein, comprised of a chain of amino acids.
Protein comes from the Greek word "protas", meaning of "prime importance". A protein is made up of complex chains of amino acids, which are the building blocks of protein. There are 20 amino acids (some believe there are 21, and there are 2-3 more not in humans), nine of which are considered "essential". What this means is the body cannot make these amino acids by itself and needs to derive them from outside sources. Non-essential amino acids are the amino acids your body can manufacture; however, when we are under severe stress or experiencing rapid growth, six of these non-essential amino acids cannot be created by our bodies. Many people confuse the term "non-essential" to mean that you do not need these for survival. All this means is that your body can create these amino acids (non-essential), and therefore it is not essential that you obtain them from other sources. The quality of a protein is determined by whether or not it is complete. The degree to which a protein can be used by the body to perform one of its functions is based on the amounts of essential amino acids it contains, and by how complete it is.
, which are the building blocks of protein. There are 20 amino acids (some believe there are 21, and there are 2-3 more not in humans), nine of which are considered "essential". What this means is the body cannot make these amino acids by itself and needs to derive them from outside sources. Non-essential amino acids are the amino acids your body can manufacture; however, when we are under severe stress or experiencing rapid growth, six of these non-essential amino acids cannot be created by our bodies. Many people confuse the term "non-essential" to mean that you do not need these for survival. All this means is that your body can create these amino acids (non-essential), and therefore it is not essential that you obtain them from other sources. The quality of a protein is determined by whether or not it is complete. The degree to which a protein can be used by the body to perform one of its functions is based on the amounts of essential amino acids it contains, and by how complete it is. 
image: bodybuildingdiet.net
A protein is called complete when it contains all nine essential amino acids. There are two types of proteins: animal protein and vegetable protein. All animal protein is considered "complete" protein because it has all nine essential amino acids. Vegetable protein, with the exception of soy foods, is considered an incomplete protein. This means that it doesn't contain all the essential amino acids, and thus isn't "complete". However, you can combine various vegetable proteins with each other or with animal proteins and create a complete protein if they contain adequate amounts of the complementary missing essential amino acids! Some examples of animal proteins include meat (all meat, whether from fish, poultry, beef, turkey, lamb etc), dairy (cheese, milk, yogurt, cottage cheese, whey protein), and eggs (in fact, egg whites are one of the only foods that are 100% pure protein, and do not contain one of the other macronutrients, such as carbohydrates or fat). Some examples of vegetable proteins include soy foods (soya, edamame, Tempeh); Quinoa (this is an ancient grain that contains a high percentage of protein), chick peas; legumes and pulses (lentils, black eye peas); nuts, seeds and some cereals. Although some of these vegetable proteins do contain all the essential amino acids, the amounts are not sufficient to properly perform their functions, and therefore must be combined with other proteins to become complete.
), and eggs (in fact, egg whites are one of the only foods that are 100% pure protein, and do not contain one of the other macronutrients, such as carbohydrates or fat). Some examples of vegetable proteins include soy foods (soya, edamame, Tempeh); Quinoa (this is an ancient grain that contains a high percentage of protein), chick peas; legumes and pulses (lentils, black eye peas); nuts, seeds and some cereals. Although some of these vegetable proteins do contain all the essential amino acids, the amounts are not sufficient to properly perform their functions, and therefore must be combined with other proteins to become complete.
*image: rothamsted.ac.uk
Why do we need protein?
Protein is the only macronutrient which provides us with Nitrogen, without which we could not exist! As mentioned previously, protein serves many important functions in the body, and is essential for every type of cell in our body. These functions can be distilled into either "catabolism" of proteins (breakdown), or "anabolism" (building up) of protein. Protein is necessary for all structure and building, and is considered the "body tissue nutrient". Anabolism occurs when amino acids are put together to build a protein, and all the amino acids needed are present. If the required amino acid is not present, then the protein cannot be formed. Catabolism takes place when we break down a protein into its constituent amino acids. Proteins are our bodies' last source of energy, and they are broken down only in the event we do not have sufficient stores of carbohydrates or fats to properly fuel us. When we break down proteins (catabolic action), we release energy.
How much do we need?
Protein needs vary vastly by age, growth rates, activity level, lifestyle, genetics, metabolism and biological factors. If we are more active, we require more protein to adequately repair the tissue we have broken down in the process. We also need more protein when we are sick, because it helps boost our immune health, while helping recover and repair our weakened bodies. People who are undergoing surgery, recovering from illness, trauma, or disease all require higher amounts of proteins as well. Although official 'government health' institututes point to a lesser amount, the general consensus is 1gram of protein to 1 lbs of body weight (more if you are active). So if you weigh 120lbs, you should ingest 120g of protein from all sources a day.
As you can see, protein truly is of "prime importance" to us, and it serves several extremely important functions. Protein enables cellular growth and repair, and is necessary for every single cell in our body.
[1] Protein amino acid chain. http://wikids.wikispaces.com/file/list?o=80
[2] The primary structure of a protein, comprised of a chain of amino acids.
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