Homocysteine is an amino acid produced in the body during the metabolism of methionine, another amino acid found in protein-rich foods. It plays a role in various bodily functions, including the production of cysteine and glutathione, which are important for cellular health. High levels of homocysteine in the blood, known as hyperhomocysteinemia, can be a risk factor for cardiovascular diseases and other health issues. Maintaining balanced levels of homocysteine is often linked to adequate intake of vitamins such as B6, B12, and folate, which help in its metabolism.