Homocysteine is a sulfur-containing amino acid that is an indicator of cardiovascular health.

    During the past few years, elevated blood levels of homocysteine have been linked to increased risk of premature coronary artery disease, stroke, and thromboembolism (venous blood clots), even among people who have normal cholesterol levels. Abnormal homocysteine levels appear to contribute to atherosclerosis in at least three ways: (1) through a direct toxic effect that damages the cells lining the inside of the arteries, (2) through interference with clotting factors, and (3) through oxidation of low-density lipoproteins (LDL).

    Elevated blood levels of homocysteine are also a biological marker associated with increased risk for many diseases (Alzheimer’s, depression, heart disease, NIDDM, multiple sclerosis, Parkinson’s, rheumatoid arthritis, stroke, and schizophrenia). A recent study in the NEJM concluded: “An increased plasma total homocysteine level confers an independent risk of vascular disease similar to that of smoking and hyper-lipidemia.” High levels of homocysteine are suspected to play a role in the development of atherosclerosis by damaging the arteries, adversely affecting the amino acids of the cell, reducing the integrity of the blood vessel walls, and suppressing the anti-clotting activity of the blood.

    Lowering the serum concentration of homocysteine has been proven to reduce the risk of adverse cardiovascular events among people with homocystinuria (a genetic disease caused by the absence of enzymes that metabolize homocysteine). Studies have not yet determined whether lowering homocysteine levels reduces the incidence of heart attacks or strokes among people with mildly elevated homocysteine levels [7,8], but many experts believe that scientific studies will prove that it does. This belief has been strongly supported by a four-year study in which 101 men with vascular disease were given supplementary doses of folic acid, vitamin B6, and vitamin B12 (which show up in significant deficiencies in this condition.) The study referred to the link between the amino acid homocysteine and cardiovascular disease and the fact that supplementing with these three vitamins has been proven to sever the link.

    Cardiovascular disease is the #1 cause of death in the U.S. (300 per 100,000 population).  At least 1,500,000 heart attacks occur every year, resulting in 489,000 deaths. Current treatment is relegated to balloon angioplasty or coronary artery bypass grafting, and lipid-reducing drugs.


    Homocysteine should be found in low levels among healthy individuals. When homocysteine levels increase, the body is unable to produce critical nutrients and compounds, which leads to chronic disease. The risk of vascular disease of the heart, brain, or peripheral vessels has been found to be directly related to homocysteine levels. These are inversely related to the levels of Vitamins B6, B12, and folic acid in red blood cells. All these vitamins are safe even in large doses.

    Risk factors include:

    • Smoking and hypertension (increase risk markedly)
    • Physical and/or psychological stress
    • Age
    • Genetic background (defective gene for homocysteine, ApoE4 genotype)
    • Gender (men have more heart disease than women, but women catch up after menopause–average 10.5 µmol/L)
    • Menopause
    • Insulin resistance and hyperinsulinemia
    • Nutrient deficiencies (especially B-complex vitamins)
    • Chronic alcohol and caffeine intake

    The disease states associated with high homocysteine levels include Alzheimer’s disease, Parkinson’s, stroke, schizophrenia disorder, coronary heart disease, Down’s syndrome, spina bifida, and cancer. There also appears to be a close connection between high homocysteine levels and cancer. Kilmer S. McCully, MD., the Harvard-trained physician behind the homocysteine theory, has published studies showing that cancer cells have very abnormal homocysteine metabolism, but more research is needed before this link can be substantiated.

    In recent years the American Heart Association (AHA) urged doctors to begin screening high-risk patients with a family or personal history of cardiovascular disease for elevated homocysteine levels.

    Screening for elevated homocysteine levels is advisable for individuals who manifest coronary artery disease or who have a family history of premature atherosclerotic disease. You must ask your health care provider to arrange a blood draw, and a laboratory can determine your homocysteine level. Normal homocysteine levels range between 8 µmol/L and 10 µmol/L. Levels above 9 or 10 µmol/L warrant treatment. The positive affects of supplementing with folic acid, vitamin B6 and vitamin B12 is usually apparent within a month.


    Improving our diet is the most important factor in reducing homocysteine levels. Eliminate refined and highly processed foods, packaged, and preserved foods. Be careful of calorie-dense, nutrient-poor foods like white flour and sugar. Eat more fresh fruits and vegetables, whole grains and legumes, and moderate fresh fish, meat, and dairy.

    Supplement Protocol

      Deficiencies of B vitamins have been linked to heart disease. The best way to lower abnormally high homocysteine levels is to take a high potency B-complex supplement. This can help to convert homocysteine to the amino acids methionine and cysteine, which are harmless to our cardiovascular systems. B vitamins are important for the production of red blood cells. Dosage: 50-100 mg daily.
      Vitamin B6 is involved in a myriad of biological processes, including the trans-sulfuration pathway of homocysteine. It is extremely important in the formation of red blood cells. Deficiencies have been linked to high levels of homocysteine and a higher risk of heart disease. Dosage: 25-200 mg daily.
      Folate is important in the metabolic process of the re-methylation of homocysteine to methionine. Methionine is the only source of homocysteine in the body. Deficiencies definitely lead to higher homocysteine levels and an increased risk of heart disease. Dosage: 400-1,200 mcg per day.
      The biological function of vitamin B12 in humans is evident, especially noted is its role in the prevention of stroke and heart disease. Since genetic and diet determine homocysteine levels, adequate amounts of vitamin B12 appear to reduce the amount of homocysteine in the blood. Injections are preferred (a prescription is needed), but vitamin B12 can be taken orally. Dosage: 500-2,000 mcg daily.
      Niacinamide helps to lower LDL cholesterol, improve circulation, and prevent premature cell death. Dosage: 500 mg daily, or as directed by practitioner.
      SAMe is a component of many proteins and cannot be manufactured from other dietary amino acids. It serves as a source of available sulfur for the synthesis of cysteine and taurine, and is important in cellular metabolism. Dosage: 200 mg twice a day.
    7. COENZYME Q10
      Coenzyme Q10 is a fat-soluble quinone occurring in the mitochondria, carrying millions of molecules of bioenergy to heart muscle cells. This antioxidant will increase the integrity of the heart cells, increase oxygenation, and lower homocysteine levels. Dosage: 50-100 mg 3 times a day.
      Antioxidants are extremely important as free-radical scavengers that boost the immune system and help to reduce high blood pressure. Free radicals accelerate the development of atherosclerosis, heart attacks, and strokes (called biological oxidation). Include adequate daily intake of VITAMIN E, VITAMIN C, ALPHA-LIPOIC ACID, BETA CAROTENE, and SELENIUM. They are the strongest group of natural antioxidants, and they help to protect the cardiovascular system from oxidative damage. Dosage: As directed on multi-antioxidant supplement.
    9. BIOTIN
      Biotin is a B-complex vitamin used for counteracting increased homocysteine levels and optimizing cell metabolism. Dosage: 1,000-5,000 mcg daily.
    10. CHOLINE
      Choline is an amino acid that reduces fat and triglyceride levels in the blood. Sources of choline include onions and garlic. Dosage: As directed on label.
      Omega 3 and 6 fatty acids help to prevent hardening of the arteries. Fish oil (DHA) is especially heart healthy by decreasing inflammation, one of the leading causes of high homocysteine levels and heart disease. Dosage: 1,000-4,000 mg daily.
      L-carnitine is a trimethylated amino acid, similar to choline, that reduces fat and triglyceride levels in the blood, increases oxygen uptake, and increases stress tolerance. Dosage: 500 mg twice a day.
    13. BETAINE
      Betaine is a plant-based source of hydrochloric acid. The metabolic pathway of betaine is interrelated with the regeneration of methionine, the only source of homocysteine in the body. Betaine supplementation has been shown to lower homocysteine levels, resulting in modest increases in plasma serine and cysteine levels. Dosage: As directed; take with other digestive enzymes.


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    Barrett, S. Homocysteine: A Cardiovascular Risk Factor Worth Considering. www.quackwatch.org, February 12, 2005.

    Bland, JS. Improving Health Outcomes Through Nutritional Support for Metabolic Biotransformation. Lecture, June, 2003.

    Gazella, KA. Homocysteine: Discovering the Truth about the Heart. Impact Communications for Nature’s Impact Magazine. 1998.

    Miller, AL, Kelly, GS. Homocysteine Metabolism: Nutritional Modulation and Impact on Health and Disease. Alternative Medicine Review, July 1997. 2(4): 234-255.

    McCully, KS. Homocysteine and Prevention of Vascular Disease. Int’l Journal of Integrative Medicine.  Jan/Feb 2001. 3(1): 23-27.

    Rath, M. Why Animals Don’t Get Heart Attacks…But People Do! MR Publishing Inc., Fremont, CA.  2003.

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