The 9 Essential Amino Acids

Every cell in the body is composed of proteins. Amino acids are the chemical substances that make up protein. Our bodies use 22 amino acids to make the 50,000 different proteins we must have to be healthy. Of the 22 amino acids there are 9 that are essential for human nutrition. An essential amino acid is one that cannot be synthesised from other available resources, and therefore must be supplied as part of the diet.

If you are vegetarian, it is not important to mix non animal amino acid sources at one meal to obtain the 9 amino acids. The reason being, that our bodies store amino acids in our blood for several hours. If we were to miss getting some amino acids in one meal, we can pick them up at some other time during the day. Non-essential amino acids don’t need to be supplied in the diet as they can be synthesised from other dietary substances.

Nearly every food, with the exception of fruits, sugars and fats and oils, has enough protein to supply our necessary amino acids if we eat enough of it to get our day’s worth of calories. We do not need to eat meat to supply the necessary protein.

The nine essential amino acids are;

1. Tryptophan: Tryptophan is a precursor for serotonin and melatonin. It is plentiful in chocolate, oats, bananas, dried dates, milk, cottage cheese, meat, fish, turkey and peanuts.

2. Lysine: Lysine deficiency can result in a deficiency in niacin (Vitamin-B) and this can cause the disease pellagra. It is also beneficial in treating and preventing herpes. Lysine sources include green beans, lentils, soybean, spinach and amaranth.

3. Methionine: Methionine supplies sulphur and other compounds required by the body for normal metabolism and growth. It belongs to a group of compounds called lipotropics that help the liver process fats. It is found in fish, whole grains, and dairy.

4. Valine: Valine is needed for muscle metabolism, tissue repair, and for the maintenance of proper nitrogen balance in the body. Valine is found in high concentration in the muscle tissue. It is also one of the three branched chain amino acids, which means that it can be used as an energy source by muscle tissue. It may be helpful in treating liver and gallbladder disorders, and it is good for correcting the type of severe amino acid deficiencies that can be caused by drug addiction. Dietary sources of valine include dairy products, grain, meat, mushrooms, peanuts, and soy proteins.

5. Leucine: Leucine is a branched chain essential amino acid that stimulates muscle protein synthesis and may be the major fuel involved in anabolic (tissue building) reactions During times of starvation, stress, infection, or recovery from trauma, the body mobilizes leucine as a source for gluconeogenesis (the synthesis of blood sugar in the liver) to aid in the healing process. It has recently been suggested that leucine may have beneficial therapeutic effects on the prevention of protein wasting, as it occurs during starvation, semi-starvation, trauma, or recovery after surgery. Insulin deficiency is known to result in poor utilization of leucine; therefore, individuals who suffer from glucose intolerance may require higher levels of leucine intake. Leucine is found in cottage cheese, sesame seeds, peanuts, dry lentils, chicken, and fish.

6. Isoleucine: Isoleucine is a branched chain amino acid that is important for blood sugar regulation, muscle development and repair, haemoglobin development, and energy regulation. Deficiencies of isoleucine result in possible dizziness, headaches, fatigue, depression, confusion and irritability. Isoleucine is found in eggs, fish, lentils, poultry, beef, seeds, soy, wheat, almonds and dairy.

7. Threonine: Threonine is important for antibody production. It can be converted into glycine and serine. Deficiencies are rare but can result in skin disorders and weakness. Dietary sources of threonine include dairy, beef, poultry, eggs, beans, nuts, and seeds.

8. Phenylalanine: Phenylalanine serves in the body as a precursor to the catecholamine family of hormones. These hormones include adrenaline and noradrenaline, which are activating substances in the central and peripheral nervous systems. Deficiencies are rare but can include slowed growth, lethargy, liver damage, weakness, oedema, and skin lesions. Food sources or phenylalanine are dairy, almonds, avocados, lima beans, peanuts, and seeds.

9. Histidine: Histidine has recently been discovered to not be synthesized in adults, which raises the list of essential amino acids in adults to nine. Histidine is one of the basic amino acids due to its aromatic nitrogen-heterocyclic imidazole side chain. This amino acid is metabolized into the neurotransmitter histamine, and the set of genes that produce the enzymes responsible for histidine synthesis.

Food sources of each of the essential amino acids are mentioned in the previous section describing each essential amino acid. In general terms proteins are found primarily in meats, eggs, milk, rice and beans, although there are also amino acids in vegetable as well. Our bodies have to break down plant or animal protein into the component amino acids and then rebuild the protein. The plant or animal protein cannot be absorbed directly because these proteins have polypeptides with hundreds, or thousands of amino acids joined in peptide bonds that have to be broken with enzymes into the single amino acids that the body can absorb, and then reform into the proteins the body requires. It is more difficult for our bodies to break down animal protein than it is for it to break down plant protein.

Other things to consider are that heat in cooking and the conditions of processing destroy many amino acids in our food. Also, vegetarians and vegans often have low intakes of the amino acid lysine that is prevalent in eggs and poultry products. Obviously, meats are the most protein dense food, followed by legumes and then grains, oats and rye.

Happy Lifting!

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