What is Homocysteine?

Homocysteine is produced by the demethylation of dietary methionine which comes from protein containing foods. Homocysteine is then  recycled back into methionine through a pathway that involves Vitamin B12 in the form of methylcobalamin and folate as a natural folate rather than synthetic folic acid.

Homocysteine is simply an intermediate in a very important biochemical pathway. Plasma homocysteine can also travel another route which involves passing of sulfur groups.  This is vitamin B6 dependent and results in the production of cysteine which can convert into the most important antioxidant in the body, glutathione.

What does an elevated homocysteine level mean in simple language?

Excess homocysteine in the circulation can damage the lining of arterial walls making them narrow and inelastic. Research suggests that a raised homocysteine level is an independent risk factor for :

• hardening of the arteries,
• coronary heart disease,
• stroke,
• peripheral vascular disease and other conditions associated with abnormal blood clotting.

Elevated homocysteine is also linked with a number of other serious medical conditions including :

• osteoporosis,
• depression,
• Alzheimer's disease,
• multiple sclerosis,
• rheumatoid arthritis,
• spontaneous abortion,
• placental abruption,
• neural tube defects (spina bifida, cleft palate, etc)
• renal failure,
• osteoporosis,
• and type II diabetes.

When homocysteine is elevated it reduces nitric oxide (NO) production which can increase risk of hypertension and erectile dysfunction.

What causes Homocysteine to become elevated?

Any road block in this pathway can cause homocysteine to elevate. When we intricately study the biochemistry of the homocysteine pathway we can see that it involves a series of conversions that require enzymes. Several nutrients, especially B vitamins, are needed for these conversions to occur.   Stress can deplete B vitamins, as can many medications.

What are ideal homocysteine levels for individuals?

Initially, levels between 8 and 15 micromol/L were considered ideal. Latest research suggests maintaining even tighter control as homocysteine levels above 6.9 micromol/L may be harmful for long-term health. A rise in serum homocysteine of 5 micromol/ L may increase cardiovascular risk by 20% to 30%. Homocysteine levels tend to rise with age.

Folic acid in a specific form, not the synthetic version in many vitamin  formulas and B12 also in an absorbable form absorption decline as we age,  so as we get older we may require higher doses of these nutrients to lower  homocysteine levels effectively. Also, medications commonly taken by these individuals deplete folic acid such as Ibuprofen and other NSAIDS.

How and how often should we test homocysteine levels?
Individuals with a personal or family history of coronary heart disease, or other CHD risk factors, or who have the MTHFR gene variation should test every 6 months.

Homocysteine Level Risk Level  

• 4.0 - 6.9 micromol/L   Optimum (low risk)
• 7 - 9.9 micromol/L Mild risk
• 10. - 12.9 micromol/L  Moderate Risk
• 13 - 20 micromol/L  High risk
• Over 20 micromol/L  Very high risk

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