Amino Acids
Amino acids information page
I have divided this article into two (2):
Part I which constitute Amino Acids derived from diet
Part II which are manufactured by the liver
Amino acids are the building blocks of protein, and unlike the two other basic nutrients - sugar and fatty acids, amino acids contain nitrogen - about 16%. Because of the vital functions of these nutrients, great care should be taken by any person concerned about their health, to ensure that sufficient amounts are supplied by the body in either dietary form, or if needed by supplementation.
Amino acids - general information
Protein is needed by every living organism, and next to water, makes up the largest portion of our body weight since it is contained in muscles, organs, hair, etc. The protein used in making up the body is not directly derived from diet, but the dietary protein is broken down into amino acids, and the body then re-constitutes these amino acids into the specific proteins needed.
Enzymes and hormones regulating body functions are also proteins. And amino acids are used in most body processes from regulating the way the body works to how the brain functions. They activate and utilize vitamins and other nutrients.
Proteins are chains of amino acids linked together, bound together with peptide bonds and there are about 28 amino acids commonly referred to in human health.
The liver manufactures about 80% of these amino acids, but the remaining 20% of such amino acids must be supplied directly by diet, and these amino acids are referred to as the essential amino acids.
These essential amino acids are:
- histidine
- isoleucine
- leucine
- lysine
- methionine
- phenylalanine
- threonine
- tryptophan
- valine
The 80% or so others that are manufactured by the liver, and which are classed as "nonessential" amino acids which will be on "Amino Acid Part II Article).
Histidine amino acid
Histidine amino acid information page
Histidine is an essential amino acid, manufactured in sufficient quantities in adults, but children may at some time have a shortage of this important vitamin. It is one of the basic (reference to pH factor) 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.
Histidine is required for
Histidine is also a precursor of histamine, a compound released by immune system cells during an allergic reaction.
It is needed for growth and for the repair of tissue, as well as the maintenance of the myelin sheaths that act as protector for nerve cells.
It is further required for the manufacture of both red and white blood cells, and helps to protect the body from damage caused by radiation and in removing heavy metals from the body.
In the stomach, histidine is also helpful in producing gastric juices, and people with a shortage of gastric juices or suffering from indigestion, may also benefit from this nutrient.
Deficiency of histidine
None known, but it is reported that an increase in the intake of this nutrient helps with the lengthening of orgasms and also more intense sexual enjoyment.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Some people take 1,000 mg of histidine two to three times per day in capsule or tablet form but it is best to work out the dosage requirements as 8-10 mg per day per kilogram of body weight.
Toxicity and symptoms of high intake
There are no reported side effects with histidine, but too high levels of histidine may lead to stress and mental disorders such as anxiety and 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.
Best used with
Best taken with B3 (niacin)) and B6 (pyridoxin).
When more may be required
Although not conclusively proven - it is thought that histidine may be beneficial to people suffering from arthritis and nerve deafness.
Other interesting points
Histidine is also used for sexual arousal, functioning and enjoyment.
Histidinemia is an inborn error of the metabolism of histidine due to a deficiency of the enzyme histidase, where high levels of histidine are found in the blood and urine, and may manifest in speech disorders and mental retardation.
Food sources of histidine
Dairy, meat, poultry and fish are good sources of histidine as well as rice, wheat and rye.
Isoleucine amino acid
Isoleucine amino acid information page
Isoleucine is an essential amino acid and is part of the three "branched chain amino acids" (BCAA) - the other two being leucine and valine. This amino acid cannot be manufactured in the body, and needs to be supplied in the diet and was first isolated in 1904 from fibrin.
Isoleucine is required for
Isoleucine, together with the other two branched-chain-amino-acids promote muscle recovery after physical exercise and on its own it is needed for the formation of hemoglobin as well as assisting with regulation of blood sugar levels as well as energy levels. It is also involved in blood-clot formation.
Deficiency of isoleucine
Deficiency of isoleucine is only found in people deficient in dietary protein but symptoms may include headaches, dizziness, fatigue, depression, confusion as well as irritability. Symptoms of deficiency may mimic the symptoms of hypoglycemia. This nutrient has also been found to be deficient in people with mental and physical disorders, but more research is required on this.
Also see leucine and valine, and look at branched-chain amindo acids.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Most people ingest enough isoleucine from their diet, although some individuals do supplement their diet with about 650 - 700 mg of isoleucine per day (based on a 70 kg body), or worked out to 10 - 12 mg per kg of body weight per day.
If you are taking a supplement of isoleucine, keep it in balance with the other two branched-chain-amino-acids leucine and valine in the formula of 2 mg of leucine and valine for each 1 mg of isoleucine.
Toxicity and symptoms of high intake
Consuming higher amounts of isoleucine is not associated with any health risks for most people but those with kidney or liver disease should not consume high intakes of amino acids without medical advise.
People ingesting higher amounts of isoleucine report elevated urination.
When more may be required
People involved with strenuous athletic activity under extreme pressure and high altitude may benefit from supplementation of this nutrient.
Food sources of isoleucine
It is present in almonds, cashews, chicken, eggs, fish, lentils, liver, meat etc.
Leucine amino acid
Leucine amino acid information page
Leucine is an essential amino acid, which cannot be manufactured in the body and is part of the three branched-chain-amino-acids. Supplements and protein powders that contain leucine are used extensively by bodybuilders and other athletes to promote muscle recovery, although it has not produced significant changes in body composition.
Leucine is required for
Leucine helps with the regulation of blood-sugar levels, the growth and repair of muscle tissue (such as bones, skin and muscles), growth hormone production; wound healing as well as energy regulation. It can assist to prevent the breakdown of muscle proteins that sometimes occur after trauma or severe stress. It may also be beneficial for individuals with phenylketonuria - a condition in which the body cannot metabolize the amino acid phenylalanine.
Deficiency of leucine
Deficiency of this nutrient is rare, since all protein foods contains it, but vegans and vegetarians without adequate protein sources may suffer from a deficiency. Hypoglycemia symptoms may appear if the diet is deficient and may include dizziness, fatigue, headaches, irritability etc.
Also see isoleucine and valine, and look at branched-chain amino acids.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
The daily dosage of leucine is about 16 mg per kilogram of body weight per day - which would translate to about 1120 mg for a 70 kg male. See good combinations as well.
Toxicity and symptoms of high intake
Consistent evidence of toxicity has not been linked to leucine supplements.
A high intake of leucine could contribute to pellagra as well as increase the amount of ammonia present in the body.
Best used with
If you are taking a supplement of leucine, keep it in balance with the other two branched-chain-amino-acids isoleucine and valine in the formula of 2 mg of leucine and valine for each 1 mg of isoleucine.
Food sources of leucine
It is found in protein foods, as well as brown rice, beans, nuts and whole wheat.
Lysine amino acid information page
Lysine is an essential amino acid and is a basic building block of all protein. This nutrient was first isolated in 1889 from casein.
Lysine is required for
It is required for growth and bone development in children, assists in calcium absorption and maintaining the correct nitrogen balance in the body and maintaining lean body mass. Furthermore it is needed to produce antibodies, hormones, enzymes, collagen formation as well as repair of tissue.
Since it helps with the building of muscle protein, it is useful for patients recovering from injuries and recovery after operations, and there might be use in lysine to help maintain healthy blood vessels. It also seems to assist in fighting herpes and cold sores.
Deficiency of lysine
Although a deficiency of lysine is rare, since it is found in so many protein foods, the symptoms may include anemia, enzyme disorders, lack of energy, hair loss, bloodshot eyes, weight loss and retarded growth as well as reproductive problems, poor appetite and poor concentration.
People on a vegan or vegetarian diet, using grains as their only source of protein are often deficient in this nutrient.
Dosage
The dosage listed is the ecommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
The daily dosage of lysine is about 12 mg per kilogram of body weight per day - which would translate to about 840 mg for a 70 kg male.
Pregnant or breast feeding mothers, as well as patients with liver or kidney problems, must first consult a health professional before taking lysine supplements.
Toxicity and symptoms of high intake
Toxicity has not been determined but animals fed high amounts of lysine, have shown a tendency to gallstones as well as elevated cholesterol - but these tendencies have not been proven in humans.
Diarrhea and stomach cramps may be indicative in high dosage, but these are not consistent symptoms.
When more may be required
Athletes, burn patients and people suffering from herpes and cold sores may benefit from an increase of lysine.
Older people could also require more lysine, as one study found older men required more of this nutrient than younger men.
Other interesting points
Lysine must be used with care in supplement form when taking antibiotics as well.
Food sources of lysine
Good sources of lysine are found in cheese, eggs, lime beans, potatoes, milk, meat and brewer's yeast.
Methionine amino acid
Methionine amino acid information page
Methionine is a sulfur containing essential amino acid and was first isolated in 1922 from casein and belongs to a group of compounds called lipotropics - the others in this group include choline, inositol, and betaine. It is important in the process of methylation where methyl is added to compounds as well as being a precursor to the amino acids cystine and cysteine.
Methionine is required for
It assists in the breakdown of fats and thereby prevents the build-up of fat in the arteries, as well as assisting with the digestive system and removing heavy metals from the body since it can be converted to cysteine, which is a precursor to gluthione, which is of prime importance in detoxifying the liver.
The amino acid methionine is also a great antioxidant as the sulfur it supplies inactivates free radicals. It may also be used to treat depression, arthritis pain as well as chronic liver disease - although these claims are still under investigation. Some studies have also indicated that methionine might improve memory recall.
It is also one of the three amino acids needed by the body to manufacture creatine monohydrate, a compound essential for energy production and muscle building.
Deficiency of methionine
Severe deficiency may manifest in dementia, while lesser deficiencies may be known by symptoms like fatty liver, slow growth, weakness, edema and skin lesions.
Dosage
The dosage listed underneath is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
The daily dosage of leucine is about 12 mg per kilogram of body weight per day - which would translate to about 840 mg for a 70 kg male.
Toxicity and symptoms of high intake
It has been suggested that a high intake of methionine, in the presence of B vitamin deficiencies, may increase the risk for arteriosclerosis (hardening of the arteries) by increasing blood levels of cholesterol and a compound called homocysteine; and that excessive methionine intake, with an inadequate intake of folic acid, vitamin B6 and vitamin B12, may increase the rate of conversion of methionine to homocysteine - both these theories have not been proven in humans.
Best used with
If you are considering taking a methionine supplement, it is best to balance it with choline and inositol.
When more may be required
People with liver problems, pancreatitis, HIV/AIDS as well as Parkinson's disease may consider obtaining more methionine, after consultation with their health professional, and older people may also benefit from a slightly higher intake of this nutrient.
Women on birth control pills could also look at this nutrient, since it promotes the excretion of estrogen. People suffering from schizophrenia could investigate taking extra methionine since it reduces the level of histidine in the body, a level normally higher in people suffering from schizophrenia.
Food sources
Methionine is found in good quantities in meat, fish, beans, eggs, garlic, lentils, onions, yogurt and seeds.
Phenylalanine amino acid
Phenylalanine amino acid information page
Phenylalanine is an essential amino acid that is also one of the aromatic amino acids that exhibit ultraviolet radiation absorption properties and is the most commonly found aromatic amino acid.
It can be converted in the body to tyrosine, which in turn is used to synthesize two important neurotransmitters - dopamine and norepinephrine. It is available in three different forms - L-, D- and DL-. The L- form is the most common and the type in which it is incorporated into the body's proteins. The D- form acts as a painkiller and the DL- a combination of the two.
Phenylalanine is required for
It is used in elevating the mood since it is so closely involved with the nervous system, as well as help with memory and learning and has been used as an appetite suppressant.
People suffering from Parkinson's disease It is DLPA (or the D- or L-form alone) is used to treat depression and the D form may also be helpful in the treatment of Parkinson's disease and chronic pain in both osteo-arthritis and rheumatoid arthritis with mixed results Increases blood levels of norepinephrine, epinephrine and dopamine - all three required for neurotransmission.
Deficiency of phenylalanine
Dietary deficiency is rare but symptoms may include lethargy, edema, weakness, skin lesions as well as liver damage and slow growth. A deficiency in diet would only occur with an extremely low protein intake.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Pregnant women, people suffering from anxiety attacks, high blood pressure, diabetes and phenylketonuria, should NOT take it. DLPA supplements may interact with certain antidepressants or stimulants. Please consult your medical professional.
The daily dosage is unknown but supplements are taken at about 14 mg per kilogram of body weight per day - which would translate to about 980 mg for a 70 kg male, but since it has powerful mood altering effects, only use under medical supervision.
Toxicity and symptoms of high intake
Toxicity is rare in dietary intake but large amounts in supplement form may play havoc with your blood pressure and cause headaches, nausea and heartburn. Large amounts of this nutrient may also cause nerve damage.
Some people cannot metabolize phenylalanine and should not take supplementation of this amino acid.
When more may be required
This nutrient could prove of benefit to people suffering from Parkinson's disease, tiredness, depression, busy with alcohol withdrawal, rheumatoid arthritis, osteo-arthritis and vitiligo.
Food sources of phenylalanine
It is contained in most protein rich foods but good sources are found in dairy products, almonds, avocados, lima beans, peanuts and seeds
Threonine amino acid
Threonine amino acid information page
Threonine is an essential amino acid, and cannot be manufactured by the body and is found in high concentrations in the heart, skeletal muscles and central nervous system.
Threonine required for
It is required to help maintain the proper protein balance in the body, as well as assist in the formation of collagen and elastin in the skin.
It is further involved in liver functioning (including fighting fatty liver), lipotropic functions when combined with aspartic acid and methionine as well as assisting the immune system by helping the production of antibodies and promotes thymus growth and activity.
Other nutrients are also better absorbed when threonine is present, and it has also been used as part treatment of mental health.
Deficiency of threonine
It is a precursor of isoleucine and imbalance may result if the synthesis rate from asparate is incorrect.
In humans, deficiency may result in irritability and a generally difficult personality.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
People taking supplements normally take a dosage ranging between 103 milligrams and 500 milligrams daily.
Threonine found in food sources
Good levels of threonine are found in most meats, dairy and eggs, as well as in lower quantities in wheat germ, nuts, beans and some vegetables.
Tryptophan amino acid
Tryptophan amino acid information page
Tryptophan is an essential amino acid and is needed to maintain optimum health.
Tryptophan required for
This amino acid is required for the production of niacin (vitamin B3). It is used by the human body to produce serotonin, a neurotransmitter that is important for normal nerve and brain function. Serotonin is important in sleep, stabilizing emotional moods, pain control, inflammation, intestinal peristalsis, etc.
It is further important in controlling hyperactivity in children, assists in alleviating stress, helps with weight loss and reducing appetite. It has also been found that people suffering from migraine headaches have abnormal levels of tryptophan, and in this supplementation may be helpful.
A shortage of tryptophan, combined with a shortage of magnesium may be a contributing factor to heart artery spasms.
Dosage
The dosage listed is the Recommende Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
In certain studies supplementation of 300 mg - 600 mg per day was experimented with to help with sleep disturbances, migraines, weight loss, appetite control, anxiety and depression, but a supplementation of 100 mg at night-time proved beneficial to promote better sleep.
Toxicity and symptoms of high intake
Supplementation with high dosage of this amino acid could lead to gastrointestinal upsets, headaches, sleepiness and anxiety.
Best used with
Vitamin B6 (pyridoxine) is required by the body for the formation of tryptophan, but people taking anti-depressants or serotonin modifying medication should be careful in taking a supplementation.
Other interesting points
Supplemental 5-HTP is derived from the seeds of the Griffonia simplicifolia, a West African medicinal plant.
Food sources of tryptophan
Good dietary sources for this amino acid are cottage cheese, meat, soy protein and peanuts.
Valine amino acid
Valine amino acid information page
Valine is an amino acid obtained by hydrolysis of proteins and was first isolated by the German chemist Emil Fischer in 1901 from casein and is not only an essential amino acid but is also a branched-chain amino acid (the others are isoleucine and leucine) found in high concentration in the muscles.
Valine required for
It has a stimulating effect and is needed for muscle metabolism, repair and growth of tissue and maintaining the nitrogen balance in the body.
Since it is a branched-chain amino acid, it can be used as an energy source in the muscles; and in doing so preserves the use of glucose.
Many amino acids become deficient with drug addiction, and here it also plays an important role and there are indications that it may also be beneficial in treating or reversing hepatic encephalopathy, or alcohol related brain damage, as well as degenerative neurological conditions.
Deficiency of valine
Maple syrup urine disease (MSUD) is caused by the inability to metabolize leucine, isoleucine, and valine. The disease is so named because urine from affected people smells like maple syrup. A deficiency may affect the myelin covering of the nerves.
Also see Isoleucine and Leucine and also look at Branded-chain amino acids.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Toxicity and symptoms of high intake
Very high levels of valine can cause symptoms such as a crawling sensation on the skin, as well as hallucinations. Individuals with kidney or liver disease should be careful in consuming high intakes of amino acids without consulting their doctor.
Best used with
The three branched-chain amino acids should always be taken in balance.
Other interesting points
Valine is often used by bodybuilders, (in conjunction with leucine and isoleucine), to promote muscle growth, tissue repair and energizer, although little scientific evidence supports these claims. Studies have however shown that these three substances might be useful in restoring muscle mass in people with liver disease, injuries, or who have undergone surgery.
Valine found in food sources
Good sources for this nutrient include dairy, meat, grain, mushrooms, soy and peanuts.
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