Dr. MJ Bazos MD,
Homocysteine (say: "ho-mo-sist-een") is an
amino acid (a building block of protein) that is produced in the human body.
Homocysteine may irritate blood vessels, leading to blockages in the arteries
How is a high
homocysteine level harmful?
High homocysteine levels in the blood can also
cause cholesterol to change to something called oxidized low-density
lipoprotein, which is more damaging to the arteries. In addition, high
homocysteine levels can make blood clot more easily than it should, increasing
the risk of blood vessel blockages. A blockage might cause you to have a stroke
or a problem with blood flow. Up to 20% of people with heart disease have high
What causes a high
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.
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, some
medicines, or inherited deficiencies in the enzymes used to process homocysteine
in the body.
How is the
homocysteine level measured, and what do the results mean?
Homocysteine is measured using a simple blood
test. It can be measured at any time of day. It is not necessary to prepare
in any special way for the blood test (such as fasting). Most hospital labs can
measure homocysteine, or a blood sample can be sent out to a special
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 12 to 15 µmol per L and you have blockages in
any blood vessel, you need to lower your homocysteine to less than 12 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).
While no studies have proved that lowering
homocysteine levels ultimately 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, chickpeas, asparagus, spinach and most beans. Folate is
sometimes called "folic acid."
If adjusting your diet is not enough to lower
your homocysteine, you will also need to take specific vitamins. You may need to
take a fairly large amount of folate (about 1 milligram per day). Additional
vitamin B6 and vitamin B12 also help the body process
homocysteine. Vitamin B supplements generally have no side
The usual recommended vitamin and folate doses
for lowering homocysteine levels are as follows:
- A daily multivitamin containing 400 µg of
folate and less than 5 mEq of iron
- An additional 800 µg of folate per day for 8
If taking these vitamins
doesn't lower your homocysteine level, your doctor may have you try a higher
dose. Or you may need to have some tests to see if you have a health condition
that causes high homocysteine levels.
It is important to get your homocysteine level
rechecked after you have been taking the multivitamin and folate for 8 weeks. If
your homocysteine level remains high, your doctor may change your treatment. You
may need to take more folate (2 mg per day). If you have had a high homocysteine
level, you will probably need to have your level checked regularly - maybe 2 or
3 times a year.