Homocysteine

Homocysteine (say: ho-mo-sist-een) is an amino acid (a building block of protein) that is produced in the human body.

High homocysteine levels in the blood can cause cholesterol to change to something called oxidized low-density lipoprotein, which damges the arteries. In addition, high homocysteine levels may make blood clot more easily than it should. This can increase the risk of blood vessel blockages. A blockage might cause you to have a stroke. It might also make a problem with blood flow, such as atherosclerosis, worse.

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 take place. Or you may not have enough of the chemicals (enzymes) your body uses to process homocysteine.

Most people with a high homocysteine level don't get enough folate (also called folic acid), vitamin B6 or vitamin B12 in their diet. Replacing these vitamins helps return the homocysteine level to normal. Other possible causes of a high homocysteine level include low levels of thyroid hormone, kidney disease, psoriasis, or some medicines.

Homocysteine is measured using a simple blood test. It can be measured at any time of day. You don't have to prepare in any special way for the blood test.

A healthy homocysteine level is less than 12 µmol per L. A level greater than 12 µmol per L is considered high. If your homocysteine level is greater than 12 µmol per L and you have blockages in any blood vessel, you need to lower your homocysteine. 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 homocysteine level (12 to 15 µmol per L).

While no studies have shown that lowering homocysteine levels helps reduce strokes, heart attacks and other cardiovascular events, it is a good idea to lower a high homocysteine level because it is a risk for heart disease.

How can I lower a high homocysteine level?
Eating more fruits and vegetables (especially leafy green vegetables) can help lower your homocysteine level by increasing how much folate you get in your diet. Good sources of folate include many breakfast cereals, lentils, asparagus, spinach and most beans.

If adjusting your diet is not enough to lower your homocysteine, your doctor may suggest that you take a folate supplement. You may also need to take a vitamin B-6 and vitamin B-12 supplement.

If you don't have enough vitamin B-6 in your diet, foods like fortified breakfast cereals, potatoes, bananas, garbanzo beans (also called chickpease) and chicken are good sources. Dairy products, organ meats (such as liver), beef and some types of fish are good sources of vitamin B-12 .

If you start taking folate or vitamin B supplements, you should have your homocysteine level rechecked after 8 weeks. If your homocysteine level remains high, your doctor may have you try a higher dose. You may need to have some tests to see if you have a health condition that causes high homocysteine levels. If you have had a high homocysteine level, you will probably need to have your level checked regularly (2 or 3 times a year).