But while the American Heart Association has not yet called hyperhomocysteinemia (high homocysteine level in the blood) a major risk factor for heart disease, it still is worth taking note of the possible association.

Advertisement

What is homocysteine?
It often happens that people who are at low risk for heart disease or stroke – people who don't smoke, exercise frequently and who have normal cholesterol and blood pressure levels – suffer an unexpected attack. Researchers are now starting to recognise that there might be several, less obvious factors at play. Homocysteine could be one of them.

Methionine, one of the amino acids used to build and maintain body tissue, is broken down into homocysteine under certain conditions. Methionine is a so-called "essential" amino acid, which means that it must be obtained from protein in the diet.

Although homocysteine is a normal component of the blood plasma, elevated levels seem to create problems. It looks like sufficient levels of folic acid can possibly keep blood plasma levels of homocysteine – also classified as an amino acid - in check. Vitamin B6 and vitamin B12 may also have a role to play.

According to Dr Carl Albrecht, South African biochemist and researcher, a diet deficient in folic acid (also classified as one of the B vitamins), vitamin B6 (or pyridoxine) and vitamin B12 can lead to an increased conversion of methionine to homocysteine in the blood.

Homocysteine is measured in micromoles. In healthy people, levels generally range from five to 15 micromoles. A reading of less than 12 is considered optimal.

The homocysteine debate
The debate concerning this amino acid is reaching a peak as researchers from around the world are publishing results of preliminary studies on the link between high blood homocysteine levels and heart disease, stroke, hypertension and peripheral vascular disease (disease of the blood vessels of the legs, feet and arms).

The role of homocysteine is, however, still controversial. Homocysteine, along with other "novel" or "new" risk factors like C-reactive protein, fibrinogen and lipoprotein (a) are all currently the objects of scrutiny. While some researchers reckon that these factors play a more significant role than the "traditional" risk factors, others are still sceptic and waiting for more substantial evidence. Several clinical trials are currently underway.

The exact mechanism is still not clear. It looks like homocysteine might be involved in damage to the endothelial lining of the artery walls – a situation that can lead to cholesterol build-up in the arteries, which can provide a surface for blood clots to form. This damage is linked to the generation of free radicals - unusually reactive, strongly oxidising atoms capable of causing a wide range of biological damage in the body.

"Homocysteine may influence the effective functioning of blood vessels. The link between atherosclerosis (hardening of the arteries) and elevated homocysteine levels has also been shown, and whilst the higher levels of homocysteine may be related to a genetic inheritance, there is a link between heart disease and folic acid deficiencies – deficiencies that can also be associated with an increased risk of blood clotting," Albrecht says.

If elevated homocysteine levels are combined with other traditional risk factors, chances of having a heart attack, stroke or peripheral vascular disease increase, some experts believe.

What to do
Ask your doctor to check your homocysteine levels if you have a strong family history of heart disease, if you experience early symptoms of heart disease, or if other risk factors, like high cholesterol, diabetes, high blood pressure, obesity, stress, smoking and lack of exercise, are at play.

If the test points to high homocysteine levels, you should seriously consider making certain lifestyle changes.

While the American Heart Association doesn't recommend widespread use of folic acid and B vitamin supplements to reduce the risk of heart disease and stroke, they do advise a healthy, balanced diet that's rich in fruits and vegetables, whole grains, and fat-free or low-fat dairy products.

For folic acid, the recommended daily value is 400 micrograms (mcg). Citrus fruits, tomatoes, vegetables and grain products are good sources. Supplements should only be used when the diet doesn't provide enough.

– (Carine van Rooyen, Health24, updated July 2008)

Any questions? Ask DietDoc

 

Print this article

Rate this article Poor 1 2 3 4 5 Excellent

JOBS

Operations Manager R20,000-25,000 Per Month Cost To Company Incl Benefits Gauteng - East Rand Financial Accountant: CA(SA) R400,000-500,000 Per Annum Cost To Company Gauteng - Johannesburg Key Account Manager Gauteng Java Developer-CT Western Cape - Cape Town Java Developer-Jozi Gauteng Account Manager R460,000-540,000 Per Annum Cost To Company Plus Benefits Gauteng Account Manager R460,000-540,000 Per Annum Market Related Plus Benefits South Africa Case Manager R210,000-220,000 Per Annum Negotiable Gauteng - Pretoria Find more jobs Register your CV Post a job