Homocysteine
is an amino acid produced in the human body by the chemical
conversion of methionine, a compound regularly consumed
within the diet. When methionine-rich foods such as
fish are eaten, the methionine is taken into the bloodstream
and into cells where a methyl group (one carbon and
three hydrogen atoms) is removed to produce homocysteine.
What are the risks of elevated homocysteine
levels?
Homocysteine is an amino acid in the blood. Epidemiological
studies have shown that too much homocysteine in the
blood (plasma) is related to a higher risk of coronary
heart disease, stroke and peripheral vascular disease.
Homocysteine can cause many problems in addition to
heart disease. If a woman is pregnant or may possibly
become pregnant, it is very important to keep homocysteine
levels low, as it can cause birth defects.
Elevated levels of homocysteine also have been linked
to increased risk of disease development and death from
common conditions, including dementia and Alzheimer's
disease, osteoporosis and diabetes.
Homocysteine is believed to have an effect on atherosclerosis
by damaging the inner lining of arteries and promoting
blood clots.
Plasma homocysteine levels are strongly influenced by
diet, as well as by genetic factors. Folic acid and
other B vitamins help break down homocysteine in the
body. Homocysteine levels in the blood are strongly
influenced by diet and genetic factors. Dietary folic
acid and vitamins B-6 and B-12 have the greatest effects.
Several studies found that higher blood levels of B
vitamins are related, at least in part, to lower concentrations
of homocysteine. Other evidence shows that low blood
levels of folic acid are linked with a higher risk of
fatal coronary heart disease and stroke.
How can I lower my homocysteine levels?
Foods
high in folic acid include green, leafy vegetables,
citrus fruits and tomatoes. Since 1998, wheat flour
has been fortified with folic acid to add an estimated
100 micrograms per day to the average diet. Folic acid
supplements should be used to lower homocysteine levels
when the diet doesn't provide enough.
Recent findings suggest that laboratory testing for
plasma homocysteine levels can improve the assessment
of risk. It may be particularly useful in patients with
a personal or family history of cardiovascular disease,
but in whom the well-established risk factors (smoking,
high blood cholesterol, high blood pressure) do not
exist. Folic acid and B-vitamin supplementation can
reduce the need to test homocysteine levels.
Vegetarians and vegans are at increased risk for elevated
levels of homocysteine, since it's virtually impossible
to have enough B12 in your diet without consuming an
omnivorous diet.
