Homocysteine is an amino acid produced by the body in the process of metabolizing proteins, so an elevated homocysteine indicates that there is some disorder in the body in the process of metabolizing proteins, or it may be caused by a deficiency of folic acid, vitamin B6 or vitamin B12. Once homocysteine is elevated, it is more dangerous to the cardiovascular system and often leads to hypertension, coronary heart disease and atherosclerosis. If homocysteine is elevated, it is important to control protein intake in the diet and to minimize the consumption of lean meat, eggs and dairy products. Folic acid, vitamin B6 and vitamin B12 can be supplemented appropriately during treatment, and blood pressure should be controlled to keep it below 140/90 mmHg.