Methionine

Methionine is an essential amino acid that plays an important role in many processes in the body, including protein synthesis and metabolism. As an essential amino acid, methionine cannot be synthesized in the human body and must be supplied by food. Methionine is involved in the synthesis of other important molecules such as cysteine, taurine, glutathione, and C-adenosylmethionine (CAMe), which are essential for healthy cells and tissues and for the regulation of many physiological processes.

Methionine is found in many foods, especially meat, fish, dairy products, beans, nuts and cereals. This amino acid is also available in the form of dietary supplements and is often included in sports nutrition, as it can help improve recovery after training and muscle mass growth.

Methionine has a number of health benefits, including antioxidant effects, maintaining liver health, and protecting against fat accumulation in the liver. However, excessive methionine intake can lead to certain health risks, especially if certain diseases or health conditions are present.

Indications Methionine

1. Support liver health: Methionine may be beneficial for people with liver disease such as cirrhosis or fatty liver dystrophy. It helps in detoxifying the body and supports healthy liver function.
2. Treatment of Chronic Kidney Failure: Some patients with chronic kidney failure may be deficient in amino acids, including methionine. Supplemental methionine supplementation may help improve their condition.
3. Metabolic disorders: Methionine may be recommended for patients with amino acid metabolic disorders such as homocystinuria and hypermethioninemia.
4. Supporting healthy skin, hair and nails: Methionine plays an important role in the formation of keratin, which forms the basis of healthy hair, skin and nails. Therefore, methionine may be helpful in improving the health of these tissues.
5. Treatment for chronic tibial neuropathy: Some studies suggest that methionine may help reduce symptoms of chronic tibial neuropathy, such as pain, numbness, and other neurological symptoms.
6. Antioxidant Defense: Methionine has antioxidant properties and may help protect cells from free radical damage.

Release form

1. Capsules and tablets: One of the most common forms used for ease of dosing and consumption. Used as dietary supplements and for medical purposes, such as correcting methionine deficiency in the diet or supporting liver health.
2. Powder: Methionine in powdered form is often used to add to sports mixes, shakes, and other nutritional products to enrich their amino acid composition. Powder may be preferred for individualized dosing or for people who have difficulty swallowing tablets.
3. Liquid solution: In medicine, methionine may be used in the form of injections or infusions for faster and more effective action, especially when amino acid deficiency needs to be corrected quickly or in emergency situations.
4. Veterinary Medicines: Methionine is also widely used in veterinary medicine in the form of tablets, powder or injections for the treatment and prevention of conditions associated with amino acid deficiency in animals.
5. Functional food additives: Methionine can be added to food products, such as baked goods, beverages or baby food, to enrich their amino acid composition or improve their nutritional value.

Pharmacodynamics

Methionine is an essential amino acid that plays unique roles in both protein structure and metabolism. It serves as an initiating amino acid in protein synthesis in eukaryotic cells. In globular proteins, methionine is usually located in the hydrophobic core. It can be oxidized to methionine sulfoxide, which can then be reduced back to methionine by the enzyme methionine sulfoxide reductase. The main metabolic function of methionine is its conversion to S-adenosylmethionine, which is the major methylating agent in biological systems. The metabolism of methionine can be divided into transmethylation, remethylation, and transsulfuration. S-adenosylmethionine through allosteric mechanisms controls these processes (Brosnan, J., Brosnan, M., Bertolo, R., & Brunton, J., 2007).

Methionine also plays a key role in the regulation of metabolic processes, including lipid metabolism and activation of endogenous antioxidant enzymes such as methionine sulfoxide reductase A, as well as in glutathione biosynthesis to combat oxidative stress. Methionine restriction may prevent impaired methionine metabolism/transmethylation, reducing DNA damage and carcinogenic processes, and possibly prevent arterial, neuropsychiatric, and neurodegenerative diseases (Martínez, Y., Li, X., Liu, G., Bin, P., Yan, W., Más, D., Valdivié, M., Hu, C.-A. A., Ren, W., & Yin, Y., 2017).

The pharmacodynamics and mechanism of action are related to several key aspects:

1. Protein synthesis: Methionine is one of the main amino acids used for protein synthesis in the body. It is the first amino acid in most polypeptides, as the start codon AUG indicates the beginning of protein synthesis and encodes methionine.
2. Metabolic pathways: Methionine is involved in several metabolic pathways in the body, including the methionine cycle and the methylation cycle. Importantly, methionine serves as a precursor for the synthesis of other important metabolites such as S-adenosylmethionine (SAM), which is a key donor of methyl groups for many biologically active molecules including DNA, RNA, proteins, and lipids.
3. Antioxidant properties: Methionine is a source of sulfur, which in turn is essential for the synthesis of the body's main antioxidant, glutathione. Glutathione plays an important role in protecting cells from oxidative stress and free radical damage.
4. Lipid metabolism: Methionine is involved in the regulation of lipid metabolism in the body, including participation in cholesterol metabolism.
5. Transmethylation: Methionine is used in transmethylation processes in which methyl groups are transferred to various biologically active molecules, which regulates their activity.
6. Amino acid metabolism: Methionine is also involved in amino acid metabolism and regulation of amino acid balance in the body.
7. Other functions: Methionine also plays a role in other processes such as detoxification of heavy metals, regulation of energy metabolism, etc.

Thus, methionine represents an important component necessary for the health and proper functioning of the body.

Pharmacokinetics

1. Absorption: Methionine is normally absorbed from food in the intestine. Its absorption may vary depending on the type of food containing methionine and other factors such as the presence of other amino acids in the food.
2. Distribution: After absorption, methionine is distributed throughout the body and is used in various tissues and organs to synthesize proteins and other biologically active substances.
3. Metabolism: Methionine can be metabolized in the body to form other substances, such as the most important metabolite, homocysteine. Homocysteine can be further metabolized to other compounds or excreted from the body.
4. Excretion: Methionine and its metabolites may be excreted through the kidneys as urea or other metabolites. Small amounts of methionine may also be excreted unchanged in the urine.
5. Half-life: Methionine does not have a half-life in the usual sense, as it is not a drug, but is a natural constituent of proteins and foods.
6. Mechanism of Action: Methionine plays a key role in metabolic processes such as methylation, trans-sulfuration and glutathione formation, and is a precursor for the synthesis of other important biological molecules.

Dosing and administration

As a dietary supplement

• Adults: The standard dose of methionine as a dietary supplement for adults may range from 500 mg to 2 g per day, divided into several meals. This dose may vary depending on individual goals such as supporting liver health, improving muscle recovery, or other specific needs.

For medical purposes

• Methionine deficiency: Dosage for correction of methionine deficiency is determined individually, based on the severity of the deficiency and the general health of the patient.
• Liver Health Support: In some cases, methionine may be prescribed to support liver health, especially for conditions leading to fat accumulation in the liver. Dosage may vary, but is usually in the range of 1 to 2 g per day.

Special instructions

• Pregnancyand breastfeeding: Women who are pregnant or breastfeeding should consult a physician before using methionine, as it is especially important for these groups to monitor amino acid intake.
• Children: The dosage for children should be closely monitored by a physician based on the child's age, weight and specific needs.

Important considerations

• Always start at the lower end of the recommended dosage range and gradually increase the dose as needed, monitoring your body's response.
• Following the dosage guidelines and recommendations of your healthcare professional will help avoid potential side effects and ensure the best results from methionine.
• An overdose of methionine can lead to adverse effects, including liver health and impairment of other organs and systems.

Use Methionine during pregnancy

There is limited data on the use of methionine during pregnancy, and its safety in pregnant women has not been fully studied. Therefore, it is important to discuss the use of methionine during pregnancy with your doctor before starting methionine.

Your doctor will be able to assess the potential risks and benefits of methionine in your particular case and make an informed decision about its use. It is generally recommended that during pregnancy you follow a balanced diet of varied and nutritious foods to ensure adequate intake of all essential nutrients.

Contraindications

1. Hypersensitivity: People with known hypersensitivity to methionine or other components of the supplement may experience allergic reactions, so its use is not recommended for them.
2. Pregnancy and breastfeeding: There is insufficient data on the safety of methionine use during pregnancy and breastfeeding. Therefore, during these periods, you should consult your doctor before starting to take methionine.
3. Kidneyfailure: People with severe renal impairment should limit their intake of methionine or consult a physician before use, as it may accumulate in the body and have adverse effects.
4. Hyperhomocysteinemia: In people with elevated blood homocysteine levels, methionine may exacerbate this condition, which may be contraindicated.
5. Liver pathology: In patients with hepatic disease, caution should be exercised when taking methionine, as it may affect metabolism in the liver.
6. Epilepsy: Some evidence suggests that methionine may worsen the seizure threshold in people with epilepsy. Therefore, people suffering from this condition should refrain from taking methionine or consult a doctor.

Side effects Methionine

1. Stomach Disorders: Some people may experience stomach discomfort, nausea, vomiting, or diarrhea when taking methionine.
2. Allergic Reactions: Some people may develop an allergic reaction to methionine. This may manifest as a skin rash, itching, swelling of the face, or difficulty breathing.
3. Urine or sweat odor: In rare cases, methionine may cause unusual urine or sweat odor. This is due to the metabolism of methionine in the body.
4. Urodynamic Disorders: Some studies suggest that consuming high doses of methionine may worsen symptoms of urodynamic disorders such as hypertension or blood pressure.
5. Changes in homocysteine levels: Prolonged use of methionine in high doses may increase homocysteine levels in the blood, which may increase the risk of cardiovascular disease.

Overdose

1. Liver Damage: Consuming high doses of methionine can cause liver problems because methionine is involved in the metabolism of sulfur, which can be toxic in large amounts.
2. Elevated homocysteine levels: Long-term and/or excessive use of methionine may increase blood homocysteine levels, which may be associated with cardiovascular risk.
3. Increased pressure in the eyes: Some studies suggest that high doses of methionine may increase pressure in the eyes, which can be a problem for people with glaucoma.
4. Gastrointestinal Problems: Methionine overdose can also cause gastrointestinal problems such as nausea, vomiting, diarrhea, or abdominal pain.
5. Other undesirable effects: Other undesirable effects such as allergic reactions, dizziness, headache, insomnia and others are possible.

Interactions with other drugs

1. Amino acid preparations: When administered concomitantly with other amino acids, methionine may compete for absorption in the intestine. This may reduce the effective absorption of methionine, especially if the intake of other amino acids exceeds that of methionine.
2. Drugs that affect amino acid metabolism: Some medicines can affect the metabolism of amino acids, including methionine. For example, some drugs to treat disorders of amino acid metabolism, such as drugs to treat homocystinuria, may alter the metabolism of methionine in the body.
3. Drugs affecting the liver: Methionine is involved in liver metabolism and detoxification. The use of drugs that affect liver function, such as hepatoprotectants or hepatotoxic drugs, may alter methionine levels in the body.
4. Drugs affecting the cardiovascular system: There is evidence that methionine may affect homocysteine metabolism, which in turn may be associated with the risk of cardiovascular disease. Certain medications, such as B vitamins, may affect homocysteine metabolism and therefore methionine levels.