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Home » Medical » Essential Nutrients » Proteins

Proteins

Proteins are essential in everybody's diet. They are known as Building blocks of life. Proteins are complex substances found in many foods and are made up of thousands of small units called amino acids. Proteins from different foods in our diet contain different amino acids. There are 20 amino acids, divided into essential and non-essential amino acids. Essential amino acids must appear in our diet because they cannot be made by the body. The 9 essential amino acids we must eat in our diet include: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, tryptophan and Valine.

When we eat foods containing protein, the digestive system breaks it down to the constituent amino acids, which enter the body "pool" of amino acids. Each cell then assembles the proteins it needs using the building blocks available. If, however, one or more of the needed amino acids is in short supply or not available at all, others that may be on hand cannot be utilized to form a protein. This is why it is important to eat a diet that contains all of the essential amino acids plus enough additional amino acids to allow for synthesis of the "nonessential" amino acids.

Proteins contain about four kcalories per gram, but the body prefers to use carbohydrate and fat as energy sources. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs, and each protein has unique functions. It is Key to muscle building and development. Proteins are constantly being broken down in our bodies. Most of the amino acids are reused, but we must continually replace some of those that are lost. This process is known as protein turnover. Our need to keep this process going begins at conception and last throughout life. Without dietary protein, growth and all bodily functions would not take place.

Proteins perform a wide variety of activities in the cell. Proteins are major structural component of all body tissue; necessary for muscular growth and cellular repair. Proteins are also a functional component of enzymes, hormones, etc. Used for energy only when carbohydrates and fats are not available. Examples are hormones, enzymes and antibodies. These are substance found in many parts of the body that helps the body to resist disease. All of the antibodies and enzymes, and many of the hormones in the body are proteins.

Proteins provide for the transport of nutrients, oxygen and waste throughout the body. They provide the structure and contracting capability of muscles. They also provide collagen to connective tissues of the body and to the tissues of the skin, hair and nails. Proteins make up living material but also hormones or enzymes. The Proteins are classified into Essential & Non-essential Amino Acids.

Kinds of Protein
  1. Complete Protein Protein from animal sources, such as meat and milk, is called complete, because it contains all nine of the essential amino acids in the right balance.

  2. Incomplete Protein Most vegetable protein is considered incomplete because it lacks one or more of the essential amino acids. Incomplete proteins found in plant foods can be mixed together to make a complete protein. As a general rule, grains, cereals, nuts, or seeds can be eaten together with dried beans, dried peas, lentils, peanuts or peanut butter. Examples of these combinations include peanut butter on wheat bread, rice and beans, and split pea soup with corn bread. Incomplete proteins found in plant foods can also be combined with small amounts of animal foods to make a complete protein. Examples include macaroni and cheese, and tuna noodle casserole.

The good news is that you don't have to eat all the essential amino acids in every meal. As long as you have a variety of protein sources throughout the day, your body will grab what it needs from each meal.

Classifiaction of Amino Acid
Essential Amino Acids Nonessential Amino Acids

1. Histidine
2. Isoleucine
3. Leucine
4. Lysine
5. Methionine
6. Phenylalanine
7. Threonine
8. tryptophan
9. Valine

1. Alanine
2. Arginine*
3. Aspartic acid
4. Cysteine*
5. Cystine
6. Glutamic acid
7. Glutamine*
8. Glycine
9. Proline
10. Serine
11. Tyrosine
Requirements

Approximately 10-15% of total daily energy intake should be consumed as protein. Protein needs for sedentary adults average about 50 grams. Growth, pregnancy, lactation, and exercise increase protein needs as indicated in the table below.

Protein Requirements
 Infants
0-6 months g/lb 1.0
6-12 months g/lb 0.72
 Children
1-3 years g/lb 0.55
4-6 years g/lb 0.50
7-10 years g/lb 0.45
 Adolescence
11-14 years g/day 46
15-18 years (total) g/day 44-49
 Young Adults
19-24 years (total) g/day 46
Pregnancy g/day 60
Lactation g/day 65
Sedentary Adult g/lb 0.4
Recreational Activity g/lb 0.5 - 0.75
Competitive Athletics g/lb 0.6 - 0.9
Muscle Bulding g/lb 0.7 - 0.9
Maximum Usable Amount 1 gram/pound body weight

Amino Acid Information:
Check that your amino acid supplement contains all the essential amino acids in the right proportions.

  • If you are taking a single amino acid as a supplement, taking it with empty stomach may help its absorption.
  • If you are taking amino acid supplements, L-Forms are recommended as they are more acceptable to the body.
  • Keep in mind, the amino acid basics; amino acids work best when all of essential and non-essential ones are provided to the body.
  • Vitamin B6 and Vitamin C are the vitamins needed for amino acid metabolism and to help with the absorption of amino acids. Include these vitamins with your amino acid supplements
  • Gelatin is the only animal protein that is not considered a complete protein.
Health benefits of amino acids

Amino acids are needed to build the various proteins used in the growth, repair, and maintenance of body tissues. Amino acids play innumerable roles in human health and disease.

  • Alanine is necessary for the promotion of proper blood glucose levels from dietary protein. It stimulates lymphocyte production and may help people who have immune suppression. It also strengthens the immune system by producing antibodies.

  • Asparagine is needed to maintain a balance, preventing over nervousness or being overly calm.

  • Carnosine is the water-soluble counterpart to vitamin E in protecting cell membranes from oxidative damage.

  • Citrulline supports the body in optimizing blood flow through its conversion to l-arginine and then nitric oxide.

  • Creatine supplements fuels and enhances short bursts of high-energy exercise. Creatine prevents the body from relying solely on the process of glycolysis.

  • Cysteine strengthens the protective lining of the stomach and intestines, which may help prevent damage caused by aspirin and similar drugs.

  • GABA has been used in the treatment of depression, manic-depressive (bipolar) disorder, seizures, premenstrual dysphoric (feeling depressed) disorder, and anxiety.

  • Glutamine regulates immune system, nitrogen shuttling, oxidative stress, muscle preservation, intestinal health, injuries, and much more.

  • Glutathione are necessary for supporting the immune system, glutathione is required for replication of the lymphocyte immune cells.

  • Glycine is an inhibitory amino acid with important functions centrally and peripherally.

  • Histidine is known to be vital in the maintenance of the myelin sheaths surrounding nerves, particularly the auditory nerve and is used to treat some forms of hearing disability.

  • Isoleucine is necessary for the optimal growth of infants and for nitrogen balance in adults.

  • L-arginine is used by the immune system to help regulate the activity of the thymus gland, which is responsible for manufacturing T lymphocytes.

  • L-carnosine supports healthy aging and cellular rejuvenation by its effects on two mechanisms: glycosylation and free radical damage.

  • Leucine is used as a source for the synthesis of blood sugar in the liver during starvation, stress, and infection to aid in healing.

  • L-theanine reduces stress and anxiety without the tranquilizing effects found in many other calming supplements.

  • Lysine is used in managing and preventing painful and unsightly herpes sores caused by the herpes simplex virus.

  • Methionine helps remove fat from the liver.
  • Phenylalanine is used to treated depression, rheumatoid arthritis and osteoarthritis, menstrual cramps, Parkinson's disease, vitiligo, and cancer.

  • Proline is an important component in certain medical wound dressings that use collagen fragments to stimulate wound healing.

  • Serine is needed for the metabolism of fats and fatty acids, muscle growth, and a healthy immune system.

  • Taurine helps regulate the contraction and pumping action of the heart muscle and it helps regulate blood pressure and platelet aggregation.

  • Threonine may enhance immunity by assisting in the production of agents that fight viral infections.

  • tryptophan is important for the production of serotonin. Increasing tryptophan may help to normalize sleep patterns.

  • Tyrosine may act as an adaptogen, helping the body adapt to and cope with the effects of physical or psychological stress by minimizing the symptoms brought on by stress.

  • Valine is useful in treatments involving muscle, mental, and emotional upsets, and for insomnia and nervousness.