Methionine

methionine

Methionine is an essential amino acid, which means the body must get it from food because it cannot make it. It contains sulfur and plays a special role as a building block for proteins and as a starting point for other important chemicals. One of its key jobs is to be converted into S-adenosylmethionine, a compound that helps the body transfer methyl groups for many chemical reactions. These methyl transfers are crucial for turning genes on and off, making neurotransmitters, and supporting normal cell function. Methionine also helps produce cysteine and glutathione, which are involved in antioxidant protection and detoxification. Good dietary sources include meat, fish, eggs, dairy, and some seeds and nuts, while plant-based diets may supply less and require careful planning. Too little methionine can interfere with growth and repair, while too much can raise levels of homocysteine, a compound linked to cardiovascular risk. Because it sits at an important crossroads in metabolism, methionine influences overall nutrition, liver function, and nutrient balance. A balanced diet and, when needed, advice from a health professional can help make sure methionine intake supports rather than harms long-term health.