Methionine is a nutritionally essential amino acid. It may be substituted with its corresponding keto acids, which on amination gives increase to methionine. The body cannot synthesize the corresponding keto acids. In microorganisms the methionine can be synthesized by methylating the homocystenine.
Weissbach and his links have exposed that for the methylation procedure, though active methionine is required yet methyl-B12 coenzyme acts as a methyl donor in change of homocysteine to methionine .
Methionine is sulphur containing necessary amino acid and was first isolated in 1922 from casein and associated to a group of compounds known as lipotropics the others in this group include inositol, choline and betaine. All these are glycogenic.
Sources of methionine
Methionine is found in excellent quantities in meat, fish, beans, yogurt, eggs, garlic, lentils, onions and seeds.
Benefits of methionine
It is used for treating endometriosis, a circumstance in which patches of endometrial tissue from the uterine lining develop outside the uterus.
It also helps 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 transformed to cysteine, which is a precursor to gluthione, which is of prime significance in detoxifying the liver.
The amino acid methionine is also a huge antioxidant as the sulfur it supplies inactivates free radicals.
It may also be used to treat arthritis pain, depression as well as chronic liver disease although these claims are still under investigation. A number of studies have also pointed that methionine might improve memory recall.
It is also one of the 3 amino acids wanted by the body to manufacture creatine monohydrate, a compound necessary for energy creation and muscle building.
It also helps to keep up healthy skin tone, well conditioned hair and strong nails.
It also helps to raise the flow of bile and cell damaging toxins away from the liver.
It helps to relieve the pain, bleeding, cramps and other complications of endometriosis.
Deficiency symptoms of methionine
Severe deficiency may outcome in dementia, while lesser deficiencies may be known by symptoms like fatty liver, slow development, weakness and edema and skin lesions.
Symptoms of high intake
It has been recommended that a high intake of methionine, in the presence of B vitamin deficiencies, may raise the risk for arteriosclerosis by increasing blood levels of cholesterol and a compound known as homocysteine
Too much methionine intake, with an inadequate intake of folic acid, vitamin B6 and vitamin B12, may raise the rate of conversion of methionine to homocysteine both these theories have not been proven in humans.
When more is needed
People with liver troubles, pancreatitis, HIV/Aids as well as Parkinson's disease may need high amounts of methionine in their diet but they should discuss with their physician before taking higher doses.
Older people may also advantage from a slightly higher intake of this nutrient.
Women on birth control pills could also advantage from this nutrient, since it promote the excretion of estrogen.
People suffering from schizophrenia could need more methionine since it decreases the level of histidine in the body, a level usually higher in people suffering from schizophrenia.
The every day dosage of methionine is about 12 mg per kilogram of body weight per day which would translate to about 840 mg for a 70 kg male.