1. Isoleucine: is one of nine essential amino acids in humans (present in dietary proteins), Isoleucine has diverse physiological functions, such as assisting wound healing, detoxification of nitrogenous wastes, stimulating immune function, and promoting secretion of several hormones. Necessary for hemoglobin formation and regulating blood sugar and energy levels, isoleucine is concentrated in muscle tissues in humans. Isoleucine is found especially in meats, fish, cheese, eggs, and most seeds and nuts.
2. Valine: is a branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway. This essential amino acid is classified as nonpolar. Valine, Leucine and Isoleucine are critical to human life and are particularly involved in stress, energy and muscle metabolism. BCAA supplementation as therapy, both oral and intravenous, in human health and disease holds great promise. "BCAA" denotes valine, isoleucine and leucine which are branched chain essential amino acids. Despite their structural similarities, the branched amino acids have different metabolic routes, with valine going solely to carbohydrates, leucine solely to fats and isoleucine to both. Because valine is hydrophobic, the hemoglobin does not fold correctly. Hypervalinemia is another example of an inborn error of metabolism involving Valine. High intake of valine and other BCAAs could cause these substances to be converted into other amino acids (or to fat for storage). Individuals with kidney or liver disease should not consume large amounts of valine or other BCAAs without first contacting a qualified health care practitioner. High Valine foods include cheese, soybeans, beef, lamb,chicken, pork, nuts, seeds, fish, beans,mushrooms, and whole grains.
3. Leucine: is an essential branched-chain amino acid important for hemoglobin formation. Leucine is one of nine essential amino acids in humans (provided by food), Leucine is important for protein synthesis and many metabolic functions. Leucine contributes to regulation of blood-sugar levels; growth and repair of muscle and bone tissue; growth hormone production; and wound healing. Leucine also prevents breakdown of muscle proteins after trauma or severe stress and may be beneficial for individuals with phenylketonuria. Leucine is available in many foods and deficiency is rare. High leucine foods include cheese, soybeans, beef, chicken,pork, nuts, seeds, fish, seafood, and beans. The interactions of leucine on glucose are not clear, to be honest. Leucine possesses both blood sugar reducing properties (can release insulin from the pancreas, can directly stimulate glucose uptake into a cell without insulin) but also the opposite (via stimulating S6K, it can inhibit insulin-stimulated glucose uptake). In a cell culture, leucine stimulates glucose uptake for up to 45 minutes and then hinders itself while in living systems acute doses of leucine do not appear to do anything remarkable (some limited evidence that leucine can be rehabilitative in diabetes, but this is preliminary). A series of cellular studies has now clearly shown that leucine directly activates a critical compound in muscle called the mTOR (mammalian target of rapamycin). It turns out mTOR is like a molecular switch that turns on the machinery that manufactures muscle proteins and leucine is one of the major activators of mTOR. So leucine not only provides the building blocks for protein synthesis, it also plays a critical role in up-regulating the process. Even when an overabundance of amino acids are available to provide the building materials for new muscle, adding extra leucine augments protein synthesis rates further. The bottom line is that adding additional leucine to your diet is an effective strategy to maximize muscle anabolism after resistance exercise. A growing body of evidence indicates that increasing leucine intake can have multiple benefits. It provides an important building block for muscle protein, activates key events in the complex process of protein synthesis, augments weight loss, improves body composition, and corrects metabolic disturbances such as elevated glucose and cholesterol levels.
The branched-chain amino acids -- leucine, isoleucine and valine -- are transported into your brain using the same pathway as the amino acid tryptophan. As a result, they compete for access to a limited number of transporters. When supplements cause high blood levels of branched-chain amino acids, less tryptophan gets into the brain. Because tryptophan is used to produce serotonin, you may subsequently have lower levels of mood- and sleep-regulating serotonin.
4. Phenylalanine: Phenylalanine is an essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE. Phenylalanine is an essential aromatic amino acid in humans (provided by food), Phenylalanine plays a key role in the biosynthesis of other amino acids and is important in the structure and function of many proteins and enzymes. Phenylalanine is converted to tyrosine, used in the biosynthesis of dopamine and norepinephrine neurotransmitters. The L-form of Phenylalanine is incorporated into proteins, while the D-form acts as a painkiller. Absorption of ultraviolet radiation by Phenylalanine is used to quantify protein amounts. Phenylalanine is an essential amino acid and the precursor of the amino acid tyrosine. Like tyrosine, phenylalanine is also a precursor for catecholamines including tyramine, dopamine, epinephrine, and norepinephrine. Catecholamines are neurotransmitters that act as adrenalin-like substances. Interestingly, several psychotropic drugs (mescaline, morphine, codeine, and papaverine) also have phenylalanine as a constituent. Phenylalanine is highly concentrated in the human brain and plasma. Normal metabolism of phenylalanine requires biopterin, iron, niacin, vitamin B6, copper, and vitamin C. An average adult ingests 5 g of phenylalanine per day and may optimally need up to 8 g daily. Phenylalanine is highly concentrated in a number of high protein foods, such as meat, cottage cheese, and wheat germ. An additional dietary source of phenylalanine is artificial sweeteners containing aspartame. As a general rule, aspartame should be avoided by phenylketonurics and pregnant women. When present in sufficiently high levels, phenylalanine can act as a neurotoxin and a metabotoxin. A neurotoxin is a compound that disrupts or attacks neural cells and neural tissue. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of phenylalanine are associated with at least five inborn errors of metabolism, including Hartnup disorder, hyperphenylalaninemia due to guanosine triphosphate cyclohydrolase deficiency, phenylketonuria (PKU), tyrosinemia type 2 (or Richner-Hanhart syndrome), and tyrosinemia type III (TYRO3). Phenylketonurics have elevated serum plasma levels of phenylalanine up to 400 times normal. High plasma concentrations of phenylalanine influence the blood-brain barrier transport of large neutral amino acids. The high plasma phenylalanine concentrations increase phenylalanine entry into the brain and restrict the entry of other large neutral amino acids (PMID: 19191004). Phenylalanine has been found to interfere with different cerebral enzyme systems. Untreated phenylketonuria (PKU) can lead to intellectual disability, seizures, behavioural problems, and mental disorders. It may also result in a musty smell and lighter skin. Classic PKU dramatically affects myelination and white matter tracts in untreated infants; this may be one major cause of neurological disorders associated with phenylketonuria. Mild phenylketonuria can act as an unsuspected cause of hyperactivity, learning problems, and other developmental problems in children. It has been recently suggested that PKU may resemble amyloid diseases, such as Alzheimer's disease and Parkinson's disease, due to the formation of toxic amyloid-like assemblies of phenylalanine (PMID: 22706200). Phenylalanine also has some potential benefits. Phenylalanine can act as an effective pain reliever. Its use in premenstrual syndrome and Parkinson's may enhance the effects of acupuncture and electric transcutaneous nerve stimulation (TENS). Phenylalanine and tyrosine, like L-DOPA, produce a catecholamine-like effect. Phenylalanine is better absorbed than tyrosine and may cause fewer headaches. Low phenylalanine diets have been prescribed for certain cancers with mixed results. For instance, some tumours use more phenylalanine than others (particularly melatonin-producing tumours called melanomas). Phenylalanine occurs naturally in many protein-rich foods, such as milk, eggs and meat. The artificial sweetener aspartame (Equal, NutraSweet), which is added to many medications, diet foods and diet sodas, contains phenylalanine.
5. Methionine: is an amino acid. Amino acids are the building blocks that our bodies use to make proteins. Methionine is found in meat, fish, and dairy products. It plays an important role in the many functions within the body. Methionine by commonly taken by mouth to treat liver disorders and viral infections along with many other uses. But there is limited scientific research that supports these uses. Methionine is a sulfur-containing essential L-amino acid that is important in many body functions. Methionine is one of nine essential amino acids in humans (provided by food), Methionine is required for growth and tissue repair. A sulphur-containing amino acid, methionine improves the tone and pliability of skin, hair, and strengthens nails. Involved in many detoxifying processes, sulphur provided by methionine protects cells from pollutants, slows cell aging, and is essential for absorption and bio-availability of selenium and zinc. Methionine chelates heavy metals, such as lead and mercury, aiding their excretion. It also acts as a lipotropic agent and prevents excess fat buildup in the liver. (NCI04) High levels of methionine can be found in eggs, meat, and fish; sesame seeds, Brazil nuts, and some other plant seeds; and cereal grains.
6. Threonine: Threonine is an essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins. Threonine is an essential amino acid in humans. It is abundant in human plasma, particularly in newborns. Severe deficiency of threonine causes neurological dysfunction and lameness in experimental animals. Threonine is an immunostimulant which promotes the growth of thymus gland. It also can probably promote cell immune defense function. This amino acid has been useful in the treatment of genetic spasticity disorders and multiple sclerosis at a dose of 1 gram daily. It is highly concentrated in meat products, cottage cheese and wheat germ. (http://www. dcnutrition. com/AminoAcids/) The threonine content of most of the infant formulas currently on the market is approximately 20% higher than the threonine concentration in human milk. Due to this high threonine content the plasma threonine concentrations are up to twice as high in premature infants fed these formulas than in infants fed human milk. The whey proteins which are used for infant formulas are sweet whey proteins. Sweet whey results from cheese production. Threonine catabolism in mammals appears to be due primarily (70-80%) to the activity of threonine dehydrogenase (EC 1. 1. 1. 103) that oxidizes threonine to 2-amino-3-oxobutyrate, which forms glycine and acetyl CoA, whereas threonine dehydratase (EC 4. 2. 1. 16) that catabolizes threonine into 2-oxobutyrate and ammonia, is significantly less active. Increasing the threonine plasma concentrations leads to accumulation of threonine and glycine in the brain. Such accumulation affects the neurotransmitter balance which may have consequences for the brain development during early postnatal life. Thus, excessive threonine intake during infant feeding should be avoided. High threonine foods include lean beef, soy, pork,chicken, liver, cheese, shellfish, nuts, seeds,beans, and lentils. The recommended daily intake of threonine is 15mg per kilogram of body weight or 6.8mg per pound.
7. Tryptophan : Tryptophan is an essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals. Tryptophan is an essential amino acid that is the precursor of both serotonin and melatonin. Melatonin is a hormone that is produced by the pineal gland in animals, which regulates sleep and wakefulness. Serotonin is a brain neurotransmitter, platelet clotting factor, and neurohormone found in organs throughout the body. Metabolism of tryptophan into serotonin requires nutrients such as vitamin B6, niacin, and glutathione. Niacin (also known as vitamin B3) is an important metabolite of tryptophan. It is synthesized via kynurenine and quinolinic acids, which are products of tryptophan degradation. There are a number of conditions or diseases that are characterized tryptophan deficiencies. For instance, fructose malabsorption causes improper absorption of tryptophan in the intestine, which reduces levels of tryptophan in the blood and leads to depression. High corn or other tryptophan-deficient diets can cause pellagra, which is a niacin-tryptophan deficiency disease with symptoms of dermatitis, diarrhea, and dementia. Hartnup's disease is a disorder in which tryptophan and other amino acids are not absorbed properly. Symptoms of Hartnup's disease include skin rashes, difficulty coordinating movements (cerebellar ataxia), and psychiatric symptoms such as depression or psychosis. Tryptophan supplements may be useful for treating Hartnup's. Assessment of tryptophan deficiency is done through studying excretion of tryptophan metabolites in the urine or blood. Blood may be the most sensitive test because the amino acid tryptophan is transported in a unique way. Increased urination of tryptophan breakdown products (such as kynurenine) correlates with increased tryptophan degradation, which occurs with oral contraception, depression, mental retardation, hypertension, and anxiety states. The requirement for tryptophan and protein decreases with age. The minimum daily requirement for adults is 3 mg/kg/day or about 200 mg a day. There is 400 mg of tryptophan in a cup of wheat germ. A cup of low fat cottage cheese contains 300 mg of tryptophan and chicken and turkey contain up to 600 mg of tryptophan per pound (http://www. dcnutrition. com). Tryptophan plays a role in "feast-induced" drowsiness. Ingestion of a meal rich in carbohydrates triggers the release of insulin. Insulin, in turn, stimulates the uptake of large neutral branched-chain amino acids (BCAAs) into muscle, increasing the ratio of tryptophan to BCAA in the bloodstream. Tryptophan is present in most protein-based foods or dietary proteins. It isparticularly plentiful in chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas, almonds, sunflower seeds, pumpkin seeds, buckwheat, spirulina, and peanuts.
The increased tryptophan ratio reduces competition at the large neutral amino acid transporter (which transports both BCAAs and tryptophan), resulting in greater uptake of tryptophan across the blood-brain barrier into the cerebrospinal fluid (CSF). Once in the CSF, tryptophan is converted into serotonin and the resulting serotonin is further metabolized into melatonin by the pineal gland, which promotes sleep. Under certain situations, tryptophan can be a neurotoxin and a metabotoxin. A neurotoxin is a compound that causes damage to the brain and nerve tissues. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of tryptophan can be found in glutaric aciduria type I (glutaric acidemia type I or GA1). GA1 is an inherited disorder in which the body is unable to completely break down the amino acids lysine, hydroxylysine, and tryptophan. Babies with glutaric acidemia type I are often born with unusually large heads (macrocephaly). Affected individuals may also have difficulty moving and may experience spasms, jerking, rigidity or decreased muscle tone, and muscle weakness. High levels of tryptophan have also been implicated in eosinophilia-myalgia syndrome (EMS), an incurable and sometimes fatal flu-like neurological condition linked to the ingestion of large amounts of L-tryptophan. The risk of developing EMS increases with larger doses of tryptophan and increasing age. Some research suggests that certain genetic polymorphisms may be related to the development of EMS. The presence of eosinophilia is a core feature of EMS, along with unusually severe myalgia (muscle pain). It is thought that both tryptophan and certain unidentified tryptophan contaminants may contribute to EMS (PMID: 1763543). It has also been suggested that excessive tryptophan or elevation of its metabolites could play a role in amplifying some of the pathological features of EMS (PMID: 10721094). This pathological damage is further augmented by metabolites of the kynurenine pathway (a tryptophan degradation pathway).
8. Histidine: is an essential amino acid that is required for the production of HISTAMINE. Histidine is a semi-essential amino acid (children should obtain it from food) needed in humans for growth and tissue repair; Histidine is important for maintenance of myelin sheaths that protect nerve cells and is metabolized to the neurotransmitter histamine. Histamines play many roles in immunity, gastric secretion, and sexual functions. Histidine is also required for blood cell manufacture and protects tissues against damage caused by radiation and heavy metals. (NCI04) Histidine is an alpha-amino acid with an imidazole functional group. It is one of the 22 protein genic amino acids. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans and other mammals. It was initially thought that it was only essential for infants, but longer-term studies established that it is also essential for adults. Infants four to six months old require 33 mg/kg of histidine. It is not clear how adults make small amounts of histidine, and dietary sources probably account for most of the histidine in the body. Histidine is a precursor for histamine and carnosine biosynthesis. Inborn errors of histidine metabolism, including histidinemia, maple syrup urine disease, propionic acidemia, and tyrosinemia I, exist and are marked by increased histidine levels in the blood. Elevated blood histidine is accompanied by a wide range of symptoms, from mental and physical retardation to poor intellectual functioning, emotional instability, tremor, ataxia and psychosis. Histidine and other imidazole compounds have anti-oxidant, anti-inflammatory and anti-secretory properties (PMID: 9605177). The efficacy of L-histidine in protecting inflamed tissue is attributed to the capacity of the imidazole ring to scavenge reactive oxygen species (ROS) generated by cells during acute inflammatory response (PMID: 9605177). Histidine, when administered in therapeutic quantities is able to inhibit cytokines and growth factors involved in cell and tissue damage (US patent 6150392). Histidine in medical therapies has its most promising trials in rheumatoid arthritis where up to 4. 5 g daily have been used effectively in severely affected patients. Arthritis patients have been found to have low serum histidine levels, apparently because of very rapid removal of histidine from their blood (PMID: 1079527). Other patients besides arthritis patients that have been found to be low in serum histidine are those with chronic renal failure. Urinary levels of histidine are reduced in pediatric patients with pneumonia (PMID: 2084459). Asthma patients exhibit increased serum levels of histidine over normal controls (PMID: 23517038). Serum histidine levels are lower and are negatively associated with inflammation and oxidative stress in obese women (PMID: 23361591). Histidine supplementation has been shown to reduce insulin resistance, reduce BMI and fat mass and suppress inflammation and oxidative stress in obese women with metabolic syndrome. Histidine appears to suppress pro-inflammatory cytokine expression, possibly via the NF-κB pathway, in adipocytes (PMID: 23361591). Low plasma concentrations of histidine are associated with protein-energy wasting, inflammation, oxidative stress, and greater mortality in chronic kidney disease patients (PMID: 18541578). Histidine may have many other possible functions because it is the precursor of the ubiquitous neurohormone-neurotransmitter histamine. Histidine increases histamine in the blood and probably in the brain. Low blood histamine with low serum histidine occurs in rheumatoid arthritis patients. Low blood histamine also occurs in some manic, schizophrenic, high copper and hyperactive groups of psychiatric patients. Histidine is a useful therapy in all patients with low histamine levels. High histidine foods include beef, lamb, cheese,pork, chicken, turkey, soy, fish, nuts, seeds, eggs,beans, and whole grains. The recommended daily intake of histidine is 10mg per kilogram of body weight or 4.5mg per pound
Although health practitioners use histidine less frequently than other amino acids, your body uses it to make histamine, which reduces your sensitivity to allergens. (Your body, however, can’t make all the histamine you need.) This amino acid can also enhance the uptake of some minerals like zinc and inhibit the absorption of copper.
Key uses of Histidine include:
Clinicians recommend this amino acid in the treatment of allergic disorders, high blood pressure, and anemia, because it helps in the formation of hemoglobin. Hemoglobin carries oxygen in the blood.
You can take histidine following an injury, because it helps form and repair tissue formation and repair.
Too high levels of histidine may lead to stress and mental disorders such as anxiety
People with schizophrenia have been found to have high levels of histidine
People suffering from schizophrenia or bipolar (manic) depression should not take a histidine supplement without the approval of their medical professional
9. Arginine: is an essential amino acid that is physiologically active in the L-form. Arginine is an essential amino acid in juvenile humans, Arginine is a complex amino acid, often found at active site in proteins and enzymes due to its amine-containing side chain. Arginine may prevent or treat heart and circulatory diseases, combat fatigue, and stimulate the immune system. It also boosts production of nitric oxide, relaxing blood vessels, and treating angina and other cardiovascular problems. Arginine is also an important intermediate in the urea cycle and in detoxification of nitrogenous wastes. (NCI04) Arginine is an essential amino acid that is physiologically active in the L-form. In mammals, arginine is formally classified as a semi-essential or conditionally essential amino acid, depending on the developmental stage and health status of the individual. Infants are unable to effectively synthesize arginine, making it nutritionally essential for infants. Adults, however, are able to synthesize arginine in the urea cycle. Arginine can be considered to be a basic amino acid as the part of the side chain nearest to the backbone is long, carbon-containing, and hydrophobic, whereas the end of the side chain is a complex guanidinium group. With a pKa of 12. 48, the guanidinium group is positively charged in neutral, acidic, and even most basic environments. Because of the conjugation between the double bond and the nitrogen lone pairs, the positive charge is delocalized. This group is able to form multiple H-bonds. L-Arginine is an amino acid that has numerous functions in the body. It helps dispose of ammonia, is used to make compounds such as nitric oxide, creatine, L-glutamate, and L-proline, and it can be converted into glucose and glycogen if needed. In large doses, L-arginine also stimulates the release of the hormones growth hormone and prolactin. Arginine is a known inducer of mTOR (mammalian target of rapamycin) and is responsible for inducing protein synthesis through the mTOR pathway. MTOR inhibition by rapamycin partially reduces arginine-induced protein synthesis (PMID: 20841502). Catabolic disease states such as sepsis, injury, and cancer cause an increase in arginine utilization, which can exceed normal body production, leading to arginine depletion. Arginine also activates AMP kinase (AMPK) which then stimulates skeletal muscle fatty acid oxidation and muscle glucose uptake, thereby increasing insulin secretion by pancreatic beta-cells (PMID: 21311355). Arginine is found in plant and animal proteins, such as dairy products, meat, poultry, fish, and nuts. The ratio of L-arginine to lysine is also important: soy and other plant proteins have more L-arginine than animal sources of protein.
10. Lysine is an essential amino acid. It is often added to animal feed.
Lysine is one of nine essential amino acids in humans required for growth and tissue repair, Lysine is supplied by many foods, especially red meats, fish, and dairy products. Lysine seems to be active against herpes simplex viruses and present in many forms of diet supplements. The mechanism underlying this effect is based on the viral need for amino acid arginine; lysine competes with arginine for absorption and entry into cells. Lysine inhibits HSV growth by knocking out arginine. (NCI04) L-lysine is an essential amino acid. Normal requirements for lysine have been found to be about 8 g per day or 12 mg/kg in adults. Children and infants need more, 44 mg/kg per day for an eleven to-twelve-year old, and 97 mg/kg per day for three-to six-month old. Lysine is highly concentrated in muscle compared to most other amino acids. Lysine is high in foods such as wheat germ, cottage cheese and chicken. Of meat products, wild game and pork have the highest concentration of lysine. Fruits and vegetables contain little lysine, except avocados. Normal lysine metabolism is dependent upon many nutrients including niacin, vitamin B6, riboflavin, vitamin C, glutamic acid and iron. Excess arginine antagonizes lysine. Several inborn errors of lysine metabolism are known, such as cystinuria, hyper dibasic aminoaciduria I, lysinuric protein intolerance, propionic acidemia, and tyrosinemia I. Most are marked by mental retardation with occasional diverse symptoms such as absence of secondary sex characteristics, undescended testes, abnormal facial structure, anemia, obesity, enlarged liver and spleen, and eye muscle imbalance. Lysine also may be a useful adjunct in the treatment of osteoporosis. Although high protein diets result in loss of large amounts of calcium in urine, so does lysine deficiency. Lysine may be an adjunct therapy because it reduces calcium losses in urine. Lysine deficiency also may result in immunodeficiency. Requirements for this amino acid are probably increased by stress. Lysine toxicity has not occurred with oral doses in humans. Lysine dosages are presently too small and may fail to reach the concentrations necessary to prove potential therapeutic applications. Lysine metabolites, amino caproic acid and carnitine have already shown their therapeutic potential. Thirty grams daily of amino caproic acid has been used as an initial daily dose in treating blood clotting disorders, indicating that the proper doses of lysine, its precursor, have yet to be used in medicine. Low lysine levels have been found in patients with Parkinson's, hypothyroidism, kidney disease, asthma and depression. The exact significance of these levels is unclear, yet lysine therapy can normalize the level and has been associated with improvement of some patients with these conditions. Abnormally elevated hydroxylysines have been found in virtually all chronic degenerative diseases and coumadin therapy. The levels of this stress marker may be improved by high doses of vitamin C. Lysine is particularly useful in therapy for marasmus (wasting) and herpes simplex. It stops the growth of herpes simplex in culture, and has helped to reduce the number and occurrence of cold sores in clinical studies. Dosing has not been adequately studied, but beneficial clinical effects occur in doses ranging from 100 mg to 4 g a day. Higher doses may also be useful, and toxicity has not been reported in doses as high as 8 g per day. Diets high in lysine and low in arginine can be useful in the prevention and treatment of herpes. Some researchers think herpes simplex virus is involved in many other diseases related to cranial nerves such as migraines, Bell's palsy and Meniere's disease. Herpes blister fluid will produce fatal encephalitis in the rabbit (http://www. dcnutrition. com).
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