The sulphurous α-amino acid L-methionine is an essential amino acid. The human body is not able to manufacture it by itself. That means that a constant blood serum level level therefore has to be maintained through nutrition and diet.
A healthy adult should consume around 19 mg of L-methionine per kilo of body weight per day, though particular conditions and circumstances can lead to a higher requirement.
Existing conditions, including allergies, liver conditions or urinary tract infections, can lead to a higher rate of use of L-methionine by the body, which is why it is necessary to consume more foods which contain this amino acid.
Nutritional supplements can also be used to ensure the increased requirement is met, otherwise the deficiency of L-methionine can cause or exacerbate depression and allergies and lead to an excess of toxins.
As the metabolisation of excess L-methionine is connected to the formation of sulphuric acid, the kidneys can use L-methionine to acidify the urine, which enables the use of this essential amino acid for the treatment of certain conditions.
For example, urine with a pH value of between 4 and 6 can optimise the effects of many antibiotics, including ampicillin, and prevent the formation of kidney stones. L-methionine can also inhibit the growth of bacteria in cases of cystitis, as most bacteria cannot survive in an acidic environment.
In addition, L-methionine can be used for artificial nutrition in intravenous drips.
Food Containing Lots of L-methionine
In total, the recommended daily requirement of L-methionine is around 2g to 3g, though this can vary due to external factors. Above all, pre-existing conditions often lead to an increase in the individual needs of the body and should therefore be treated with the relevant supplementation.
As this amino acid cannot be produced by the body itself, it is necessary to ensure an intake through nutrition and/or supplementation – almost all foods containing protein also contain L-methionine.
There is hardly any difference between plant-based and animal products regarding the amount of L-methionine contained within it and the bioavailability. As L-methionine is fairly soluble, foods containing L-methionine shouldn’t be boiled or soaked for too long, as this can result in significant amounts being washed out, leaving only a small amount for the body to absorb.
High temperatures during cooking or baking can also irreparably destroy the structure of the amino acids, and a prolonged exposure to heat leads to a complete loss of this vital substance from the food.
Brazil nuts are the best known source of L-methionine, as they contain around 1000mg per 100g. Additionally, Brazil nuts, actually the seeds from a Brazil nut tree, contain multiple unsaturated fatty acids, which also have numerous positive effects on the human body, for example, the destruction of free radicals and the regeneration of multiple types of tissue, and as a result help protect the body from harmful influences.
Other foods which can be used to meet the daily requirement of L-methionine are:
- Sesame seeds (around 586mg of L-methionine per 100g)
- Raw salmon (around 626mg per 100g)
- Beef (around 554mg per 100g)
- Chicken breast fillet (around 552mg per 100g)
- Dried soya beans (around 547mg per 100g).
Green vegetables, including broccoli, sprouts and spinach, can also contribute to an adequate supply of L-methionine. However, in order to use this substance in medical treatment, a specifically-designed nutritional supplement with a special amino acid compound is needed.
Functions of L-methionine
L-methionine is a precursor of L-Cysteine and L-Taurine and is essential for the synthesis of these substances. Additionally, L-methionine has antioxidant properties and can therefore protect the body from toxic substances and free radicals.
It reacts with the damaging substances thereby preventing other substances or cells from being destroyed.
The capacity of the body to excrete substances through urine is affected by the amount of L-methionine in the body and a deficiency can lead to problems in this area, such as fluid retention and oedemata.
At the same time, susceptibility to infections and the tendency towards arteriosclerosis and hair loss increases. It is therefore important to ensure the sufficient intake of this vital substance, and relevant supplements can be used to this end.
L-methionine influence many functions within the body as one of the building blocks for several critical proteins and hormones, for example, L-Carnitine, adrenaline, choline and melatonine. L-Carnitine is necessary for the energy metabolism of the body and enables the transport of long-chain fatty acids through the mitochondrial membrane.
The neurotransmitter adrenaline acts as a stress hormone and puts the whole body on red-alert in dangerous situations; the blood pressure is raised and energy reserves are activated, among other things. Choline also reacts to transmit stimuli, by enabling the synthesis of the neurotransmitter acetylcholine.
This is responsible for the transmission of nerve impulses to the heart and controls the transmission of stimuli between the nerves and muscles. Melatonin is necessary for the maintenance of the sleep cycle of the body, enabling healthy and restful sleep.
L-methionine is also responsible for the reduction of the level of histamine in the blood, which is why it can positively affect the symptoms of allergies. In addition, it is important for the regulation of the acid-base balance and provides sulphur atoms for various chemical processes.
In this way, it can also contribute to the detoxification of heavy metals (such as mercury from dental fillings) through the formation of complexes and of cartilage.
The Medical Uses of L-methionine
L-methionine is involved in the synthesis of a number of different substances and contributes therefore to the maintenance of health and fitness, which is why it can be seen as a vital substance. Additionally, it influences many physiological processes and can therefore be used in the prophylaxis and treatment of certain conditions.
Prevention of Urinary Tract Infections
As L-methionine leads, among other things, to the acidification of urine, it can be used effectively to prevent urinary tract infections, as E. coli, which is usually responsible for cystitis, cannot survive in an acidic environment.
A study in 2002 demonstrated that the additional consumption of supplements containing L-methionine can markedly reduce the tendency for urinary tract infections. 1.
The use of supplements containing L-methionine is particularly beneficial for young women, who suffer from cystitis much more regularly than other segments of the population. Supplementation can also effectively reduce the risk of the reoccurrence of the infection.
L-methionine Can Lighten Your Mood
The treatment of depression and Parkinson’s disease can also be complemented by the use of L-methionine, as it is involved in many of the metabolic processes in the brain. It encourages the production of the mood-lifting neurotransmitter serotonin and can improve the ability of those suffering from Parkinson’s to move and be active.
When the relevant supplementation is used, it restores a chemical balance, thus reducing symptoms including trembling, erratic mood swings and sleep disorders. After this was proven by Polish researchers last year, L-methionine has increasingly been used in the treatment of degenerative neurological conditions. 2
L-methionine is an essential amino acid and of great importance for the human body, as it is involved in the formation of many substances containing protein, as well as providing sulphur.
It is necessary for the bonding and excretion of toxic heavy metal compounds and is also capable of pushing the pH-value of urine into the acidic part of the scale, reducing the occurrence of cystitis and other urinary tract infections.
The effectiveness and efficiency of ampicillin and other antibiotics is also improved where the pH-value ranges between 4 and 6. Finally, L-methionine can reduce the severity of depression or Parkinson’s and otherwise improve the quality of life of those suffering from such conditions.
- “Günther M, Noll F, Nützel R, Gläser E, Kramer G und Stöhrer M: Harnwegsinfektprophylaxe – Urinansäuerung mittels L-Methionin bei neurogener Blasenfunktionsstörung. Der Urologe (B). 2002; 218-220 ↩
- “Krzystanek M, Pa?asz A, Krzystanek E, Krupka-Matuszczyk I, Wiaderkiewicz R, Skowronek R. (S-adenosyl L-methionine in CNS diseases). Psychiatr Pol. 2011 Nov-Dec;45(6):923-31. Review.” ↩