High Levels of Homocysteine Increase the
Risk of Cardiovascular Disease
In 1969, Dr. Kilmer McCully
published in
the American Journal of Pathology a report that high-normal serum levels of
homocysteine constituted a risk factor for cardiovascular
disease. A study published in 1976 by Wilcken and Wilcken supported
this premise, who reported that, following an oral dose of
methionine, serum homocysteine levels tended to be higher in
patients with premature coronary disease than in healthy controls.
Nonetheless, the thesis that homocysteine is an important
determinant of vascular disease in the general population attracted
little interest until Dr. Meir Stampfer and his colleagues at
Harvard, using data from the large Physicians' Health Study,
provided striking confirmation: the risk of
myocardial infarction was threefold higher in subjects with
homocysteine levels in the top 5% of values, compared to subjects
with homocysteine in the bottom 90%.
Subsequently, a number of other
studies have concluded that high homocysteine levels represent an
important independent risk factor for coronary heart disease, heart
attack, stroke, peripheral atherosclerosis, and venous
thromboembolism (the blockage of a blood vessel by a migrating
clot). Furthermore, the risk associated with homocysteine appears to
increase throughout the normal range of concentrations; each 1
micromolar rise in the concentration of homocysteine in the blood
corresponds to an increase of about 10% in cardiovascular risk. This
homocysteine-associated risk is strongly enhanced by smoking and
hypertension. For reasons not yet clear, homocysteine levels tend to
be higher in males, the elderly, smokers, and caffeine users. In
light of evidence that homocysteine can be directly toxic to blood
vessels—in particular, much like oxidized LDL cholesterol, it
disrupts the healthful function of the cells lining the blood
vessels—it seems likely that homocysteine is not merely a
marker for some other pathogenic (disease causing) factor. It is
therefore highly desirable to develop and implement safe measures
for minimizing serum homocysteine levels.1
What is Homocysteine?
Homocysteine is an amino acid in
the blood. It is acquired from eating meat. 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. Plasma homocysteine levels are strongly
influenced by diet, as well as by genetic factors. The dietary
components with the greatest effects are folic acid and vitamins B6
and B12. Folic acid and other B vitamins help break down
homocysteine in the body. Several studies have found that higher
blood levels of B vitamins are related, at least partly, 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.2/3
According to the Mayo Clinic, excessive levels of
homocysteine in your blood may increase your risk of stroke, certain
types of heart disease, and disease of the blood vessels of the
arms, legs and feet (peripheral artery disease).4
The Homocysteine Debate
Kilmer McCully determined that inflammation, not
cholesterol, was the cause of atherosclerosis and increased
cardiovascular risk and that homocysteine was the direct cause of
this vascular inflammatory process in at least 40% of cases.
McCully, through a lifetime of medical detective
work, had single-handedly and methodically not only discredited the
role of cholesterol and the entire low fat / low cholesterol diet
debacle but introduced the inflammatory concept of atherosclerosis,
now accepted by many, and placed homocysteine firmly in the center
of it.5
But this concept has not been widely accepted by
the medical business. The AMA and the Heart Association do not
endorse having a blood test for homocysteine levels. Instead, the
established medical business acknowledges there might be a
relationship to homocysteine levels and coronary issues but the real
problem are cholesterol levels. Dr. Ladd McNamara says the reason
for this is there is are drugs that affects cholesterol levels
regardless if this is a actual health issue. But there are no drugs
that impact homocysteine levels. Folic acid, and the B vitamins do
lower homocysteine levels. So until the drug companies can come up
with a drug that lowers homocysteine levels, you have to request
your own test and probably at your own expense since insurance
companies do not recognize it as an acceptable test.
Get your blood tested for your Homocysteine
levels - your MD will not order the test you have to request it.
The clear message from recent scientific findings
is that there is no safe “normal range” for homocysteine. Commercial
laboratories state that normal homocysteine can range from 5 to 15
micro moles (units of molecular weight) per liter of blood. Research
data reveals that homocysteine levels above 6.3 can cause a steep
progressive risk of heart attack. One study found
each 3-unit increase in homocysteine caused a 35% increase in heart
attack.6
A homocysteine increment of 5 mmol/L has been
associated with a 49% increase in all-cause mortality, a 50%
increase in cardiovascular mortality, a 26% increase in cancer
mortality, and a 104% increase in non-cancer, non-cardiovascular
mortality.7
C-reactive protein
C-reactive protein (CRP) is a protein produced by
your liver as part of an immune system response to injury or
infection. CRP is also produced by the muscle cells in the coronary
arteries.
It is a marker for inflammation somewhere in the
body. However, the CRP tests do not pinpoint exactly where in the
body inflammation is occurring. Inflammation plays a major role in
atherosclerosis, in which fatty deposits clog your arteries. While
measuring CRP alone won't tell your risk of heart disease, factoring
in CRP test results with other blood tests results and risk factors
for heart disease helps create an overall picture of your heart
health.
High levels of CRP in your blood may be associated
with an increased risk of heart attack and sudden cardiac death.
High levels of CRP appear to be less useful in predicting your risk
of a stroke.4
Sources:
- Linus Pauling Institute -
The Vascular Toxicity of Homocysteine and
How to Control It
- American Heart Association -
What is Homocysteine? October 16, 2008
- WebMD -
Heart Disease: Homocysteine: A New Heart Disease Risk Factor -
December 01, 2006
- Mayoclinic.com -
Blood tests for heart disease -
- Spacedoc.net -
The
Homocysteine Debate by Duane Graveline MD MPH
Former USAF Flight Surgeon
Former NASA Astronaut Retired Family Doctor
-
Tinnitusformula.com -
Homocysteine:
Health Concerns and Hearing Loss
-
HSFighters.com -
What Is A Safe
Homocysteine Level?
Links: