Methionine (methionine) is the only sulfur-containing essential amino acid in the human body. Its core functions revolve around protein synthesis, as a methyl donor, antioxidant, liver protection, detoxification, cardiovascular and hair health, covering six aspects. It is a key hub in life metabolism.

1. Protein Synthesis (Basic Core)

As the initiating amino acid for protein synthesis, it is the "promoter" for the synthesis of all polypeptide chains, determining whether protein synthesis can be initiated.

It is a necessary raw material for all proteins such as muscles, organs, enzymes, antibodies, hemoglobin, etc. Lack of it will directly lead to growth retardation, muscle loss, weakened immunity, and impaired tissue repair.

2. Methyl Donor (Metabolic Core)

Methionine → S - adenosylmethionine (SAM), which is the most important methyl donor in the body.

It participates in DNA/RNA/protein methylation, regulating gene expression, cell differentiation and repair.

It synthesizes choline (lecithin), creatine, adrenaline, noradrenaline, supporting nerve, muscle, and cardiovascular functions.

3. Antioxidation and Free Radical Clearance

It is the core sulfur source of glutathione (GSH), which is the strongest antioxidant in the cell, eliminating free radicals and protecting cell membranes and DNA.

It can be oxidized to methionine sulfoxide and then repaired by reductase, forming an antioxidant cycle, delaying cell aging.

4. Liver Protection and Fat Metabolism

It promotes choline synthesis, accelerates the transport and breakdown of liver fat, preventing fatty liver and alcoholic liver.

It enhances the liver's detoxification ability, protecting against drug, chemical toxin, and heavy metal poisoning.

It reduces bile stasis and maintains normal liver and gallbladder functions.

5. Detoxification and Heavy Metal Excretion

It provides methyl and sulfhydryl groups, methylating / combining heavy metals such as arsenic, lead, mercury, and drugs/toxins, accelerating their excretion from the body.

It assists the liver in metabolizing alcohol and drugs, reducing liver damage.

6. Cardiovascular and Hair Health

It participates in homocysteine metabolism, reducing homocysteine in the blood, reducing the risk of atherosclerosis and thrombosis.

Sulfur is the core component of keratin, maintaining black and thick hair, tough nails, and elastic skin.

7. Other Key Functions

It synthesizes cysteine and taurine, participating in bile acid metabolism, retinal function, and nerve regulation.

It participates in the synthesis of polyamines, supporting cell proliferation, DNA replication, and tissue repair.

Deficiency Symptoms

Growth retardation, muscle atrophy, fatty liver, abnormal liver function, dry and brittle hair, fragile nails, weakened immunity, fatigue, decreased detoxification ability.

Main Food Sources

Animal protein: eggs, fish meat, poultry meat, red meat, dairy products (the highest content).

Plant protein: soybeans, nuts, whole grains (lower content, mostly the first limiting amino acid).

———————"From Doubao AI"