Homocysteine has been the subject of many newspaper and magazine articles recently for its possible effect on cardiovascular disease. Homocysteine is an amino acid produced as a normal byproduct of the breakdown of methionine, which is an essential amino acid acquired mostly from eating meat. High homocysteine levels have been linked to a variety of vascular and heart diseases, including heart attack, stroke, blood clots and other cardiovascular problems. Though homocysteine has been independently associated with an increased risk for cardiovascular disease in some studies, a causal link has not been definitively established.

Because of these findings, there is debate over an appropriate role for the screening and treatment of elevated homocysteine levels. On the one hand, elevated homocysteine levels are clearly associated with adverse cardiovascular effects. On the other hand, few studies have shown that treating elevated homocysteine levels can actually lower the number of people who get heart disease.

Elevated homocysteine levels can be treated with three B-vitamins: vitamin B-6, vitamin B-12 and folic acid (the synthetic and more easily absorbed version of folate). Of these, folate and vitamin B-12 are the most effective in lowering homocysteine levels, and vitamin B-6 has less effect. The decision to treat elevated homocysteine levels usually depends on the patient’s overall risk level for developing heart disease. People who are at higher risk are more likely to be treated, although all individuals should make sure they get enough of the important B vitamins in their diet.

Similarly, the decision to screen for elevated homocysteine levels depends on the presence of other risk factors, such as a family history of heart disease. Currently, the American Heart Association (AHA) does not recommend widespread screening for elevated homocysteine, as is recommended for blood pressure and cholesterol. Instead, the AHA recommends that people who are already at risk may consider having their homocysteine levels checked.