Homocysteine is a kind of amino acid that is transported in your blood. Although a direct causal link has not yet been conclusively established, it is believed that a high level of homocysteine in the plasma of the blood indicates an increased risk of coronary heart disease, peripheral vascular disease or stroke. It has also been suggested that high homocysteine levels may promote the formation of blood clots in arteries. It is believed that the liver plays an important role in controlling the levels of homocysteine in your blood.
Levels
Factors that affect homocysteine levels in blood plasma include your diet and genetic factors, according to the American Heart Association. If your diet contains adequate levels of folic acid and the vitamins B12 and B6, these will function to break down homocysteine. As of 2010, it is uncertain whether lowering your homocysteine levels will, in itself, reduce your risk of coronary heart disease.
Testing
According to the American Heart Association, testing for homocysteine levels in blood plasma is helpful in assessing an individual's overall risk for cardiovascular disease. Homocysteine testing may be particularly helpful in assessing risk factors for a person with a family history of cardiovascular problems. Testing homocysteine levels can establish relative risk in such a person when the more commonly known risk factors for cardiovascular disease--such as smoking, high blood pressure or high cholesterol--are not present.
Theories/Speculation
The September 2000 issue of "The Biochemical Journal" reports a study on homocysteine metabolism in the livers of rats. This study found that a high level of protein in the rats' diet had a significant effect in raising their overall levels of plasma homocysteine. The results of the study suggested that the liver plays a vital role in regulating levels of plasma homocysteine. If this is the case in rats, it may also be true that homocysteine is regulated by the liver in humans. However, controlled human studies would be necessary to prove or disprove this hypothesis.
Expert Insight
In the May 2001 issue of the journal "Hepatology Research," a group of German researchers led by Dr. Bosy-Westphal report that patients with liver cirrhosis are more likely than non-cirrhotic patients to have elevated homocysteine levels in blood plasma. The study examined 43 patients with proven cirrhosis of the liver, and found that almost three-quarters of these patients had significantly elevated homocysteine levels.
Warning
Liver disease and cardiovascular diseases can be very serious, and you should not hesitate to seek individual medical advice from your own primary care physician if you have any concerns about risk factors for cardiovascular disease or liver cirrhosis. The relationship between homocysteine and the liver is still not fully understood or proven, and further studies in humans are necessary before any firm conclusions may be drawn.
