Homocysteine is an amino acid (a building block of protein) that is produced in the human body normally.

How can homocysteine harm my body?

One theory is that homocysteine somehow interferes with the secretion of nitric oxide, which helps regulate blood pressure by relaxing and expanding blood vessels when blood flow increases. Another theory is that homocysteine is partly responsible for atherosclerosis, the dangerous build up of fatty substances in arteries.

High homocysteine levels in the blood can cause cholesterol to rise, which again is more damaging to the arteries.

High homocysteine levels can make blood clot more easily than it should, increasing the risk of blood vessel blockages.

Up to 20% of people with heart disease have high homocysteine levels. The arteries of animals injected with homocysteine showed changes that lead to the buildup of atherosclerotic plaques.

How is the level of homocysteine raised?

Homocysteine is normally changed into other amino acids for use by the body. If your  homocysteine level is too high, you may not have enough B vitamins to help this process. Or you may not have enough of the chemicals (enzymes) to process homocysteine.

Possible causes of a high homocysteine level include:

• Most people with a high homocysteine level don't get enough folic, vitamin B6 or vitamin B12 in their diet. Replacing these vitamins helps return the homocysteine levels to normal.
• Low levels of thyroid hormone.
• Kidney disease.
• Psoriasis.
• Some medicines.
• Inherited deficiencies in the enzymes used to process homocysteine in the body.

How do I know if my homocysteine level is high or not?

Homocysteine is measured using a simple blood test. It can be measured at any time of the day. It is not necessary to prepare in any special way for the blood test (such as  fasting).

Healthy homocysteine level = less than 12 µmol per L.
Level greater than 12 µmol per L = high.
If your homocysteine level is 12 to 15 µmol per L and you have blockages in any blood vessel, you need to lower your homocysteine to less than12 µmol per L.

If you have no other major risk factors for cardiovascular disease and you do not have atherosclerosis, it may be okay for you to have a modestly high level of homocysteine (12 to 15 µmol per L) in your body.

Unlike cholesterol, which is considered problematic when it rises above 200 milligrams per deciliter, researchers haven't set a "safe" level of homocysteine. Researchers at the University of Washington estimated that an increase of 5 micromoles of homocysteine per liter is equivalent to a 20-milligrams per deciliter increase in cholesterol.

They also concluded that a 5-u.mol/L increase in homocysteine levels raises coronary artery disease risk as much as a 20-mg/dL rise in cholesterol.

Is there anything I can do to lower my homocysteine level?
The good news is that homocysteine levels can often be managed with diet.

Three nutrients in particular can help lower elevated homocysteine levels:

• Folic acid : which is abundant in green leafy vegetables, oranges and fortified cereals.
• Vitamin B-6 : found in meats and fortified cereals.
• Vitamin B-12 : found in meats, potatoes, bananas and fortified cereals.

These nutrients are believed to help keep homocysteine in check by helping it convert into other substances in the blood that aren't associated with heart disease.

Eating more fruits and vegetables (especially leafy green vegetables) can help lower your homocysteine level by increasing how much folic acid you get in your diet.
 
One way to insure adequate folic acid intake is to eat 5 daily servings of fruits and vegetables. Among the best natural sources of folic acid are green leafy vegetables, beans citrus fruits, lentils, chickpeas, chicken giblets, turnip greens, avocado, asparagus, orange juice and spinach.
In January 1998, wheat flour became fortified with folic acid to add an estimated 100 micrograms per day to the average diet.

If adjusting your diet is not enough to lower your homocysteine, you will also need to take specific vitamins. You should discuss this with your own GP .You may need to take a fairly large amount of folic acid.

Additional vitamin B6 and vitamin B12 also help the body process homocysteine. Vitamin B supplements generally have no side effects.
Several studies have found that higher blood levels of B vitamins are related, at least in part, to lower concentrations of homocysteine. Other recent evidence shows that low blood levels of folic acid are linked with a higher risk of fatal coronary heart disease and stroke.

Researchers have studied varying amounts of folic acid to lower homocysteine levels, but it's still not clear what an optimal dose might be and to what extent a dietary supplement might be required to lower homocysteine levels.