Homocysteine is an amino acid that is produced by the body, usually as a byproduct of consuming meat. It is chemically transformed into methionine and cysteine (similar amino acids) with the help of folic acid, vitamin B12, and vitamin B6.
The normal level of homocysteine is between 5 to 15 micromoles (measurement unit of small amount of a molecule) per liter.
Elevated levels are classified:
- 15-30 micromoles/ liter as moderate
- 30-100 micromoles/liter as intermediate
- More than 100 micromoles/liter as severe hyperhomocysteinemia
Elevated homocysteine level can be associated with atherosclerosis and an increased risk of heart attacks, strokes, blood clot formation, and possibly Alzheimer's disease. Homocysteine levels can be also elevated because of severe genetic causes and other milder cases.
For example, in the genetic condition called homocystinuria, there is a deficiency or lack of an important mediator molecule (enzymes) in the complicated homocysteine breakdown pathway.
Mild hyperhomocysteinemia can be found in alcoholics and some people because of poor vitamin taking and in patients with chronic kidney disease.
In theory, hyperhomocysteinemia cause atherosclerosis (narrowing and hardening of the arteries) through a variety of ways and increases the tendency to excessive blood clotting which can cause a heart attack because of lack of blood supply to the heart muscles and strokes due the lack of blood supply to the brain.
Also, elevated homocysteine levels can be associated with the formation of blood clots in veins (deep vein thrombosis and pulmonary embolism), similar as in atherosclerosis.
For now, there is direct proof that taking folic acid and B vitamins can prevent heart attacks and strokes but in on large study involving women, those who had the highest consumption of folic acid had fewer heart attacks than those who consumed the least amount of folic acid.
For now, there are no official recommendations which patients should undergo testing for Homocysteine blood levels and many experts do not recommend a test and treating elevated homocysteine level with vitamins until more scientific data become available.
Also, there is no consensus on the optimal dose of folic acid and another B vitamin for the treatment. Usual daily recommended doses by the Food and Drug Administration (FDA) are: for foliate supplementation 1 milligram daily, vitamin B6 milligram per day, and vitamin B12 one-half milligram per day.
Doctors usually the test in patients with early onset of blood clot formation, heart attacks, strokes, or other symptoms related to atherosclerosis, especially if these patients do not have typical risk factors, such as smoking cigarettes, diabetes, high blood pressure, or high LDL cholesterol levels.
A person can prevent heart attacks and strokes by losing excess weight, exercising regularly, controlling diabetes and high blood pressure, lowering the bad LDL cholesterol, and stopping cigarette, eating more fresh fruits and vegetables, eat less saturated fat and cholesterol, and take one multivitamin daily because it supplies 400 mcg (microgram or one-one thousandth of a gram)/day of folic acid in addition to vitamins B6, B12, and other important vitamins.