Homocysteine is a naturally occurring amino acid found in blood plasma. It is broken down in the body through two metabolic pathways. The chemical changes that must occur to break down homocysteine require the presence of folic acid (also called folate) and vitamins B6 and B12. The level of homocysteine in the blood is influenced by the presence of these substances.
Vitamin B12 is is a water-soluble vitamin needed for normal nerve cell activity, DNA replication, and production of the mood-affecting substance. Vitamin B12 acts with folic acid and vitamin B6 to control homocysteine levels. An excess of homocysteine is associated with an increased risk of heart disease, stroke, and potentially other diseases such as osteoporosis and Alzheimer’s disease. please see chart below.