Homocysteine and Heart Disease

~ January 1999 No.64 ~

Heart disease continues to be the leading killer in the western world. Many factors that can increase the risk of heart disease have been identified. If you do nothing else - quit smoking or better still, don’t start. Diet has always been considered to be an important risk factor. Many foods in our diet have been shown to decrease the risk of coronary artery disease. Others may increase the risk. There has been a feeling for some time that there may be "something else" that could be contributing to heart disease. Homocysteine may be that "something else".

Homocysteine is an amino acid. All protein is made up of building blocks called amino acids. Each amino acid has an NH2 or amine group in its molecule, but, aside from that, the structures of amino acids vary. Homocysteine is one of the few amino acids that contains sulphur. Homocysteine is important because it is a necessary component in the metabolism of methionine - another sulphur containing amino acid.

So what does homocysteine have to do with heart disease? That’s not all that easy to explain. It has been almost chance observations that have pointed to homocysteine as a culprit. Just like the incidence of heart disease, blood homocysteine levels tend to rise with age; they increase due to renal impairment, increase in women after menopause, and are higher in men compared to women of the same age. Studies have shown that blood levels of homocysteine are elevated in coronary artery disease patients compared to a control population when the patients are younger than 50 years old. Sufferers of coronary artery disease often have blood homocysteine levels of greater than 15 ┬Ámol/L which is considered by many to be high.

How important can blood homocysteine be? At least one researcher has warned that elevated blood levels of homocysteine can be as dangerous as smoking and having high blood lipid levels.

The good news is that blood homocysteine levels can be reduced by increasing the amounts of folic acid and vitamin B12 in the diet. These two vitamins help in the metabolism of homocysteine

Chemical Structure of Homocysteine


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Last modified

July 19 2015