What Is Homocysteine?

HCA image for aging hearts Homocysteine is an amino acid formed in the body from another amino acid called methionine. Certain B vitamins are needed to breakdown these amino acids. The vitamins include vitamin B6, vitamin B12, and folate. A deficiency of any one of these vitamins, most particularly folate, can lead to an elevation in blood levels of homocysteine.

Does Homocysteine Increase the Risk of Heart Attack?

Levels of homocysteine increase with age, and elevation is more common in men and postmenopausal women. Although some studies have found and association with high homocysteine levels and heart disease, whether or not homocysteine is a risk factor for heart disease remains controversial.

Very high levels of homocysteine were first found to be a problem in the 1960s, when people with an inheritable defect of an enzyme responsible for the metabolism of homocysteine were suffering from heart attacks and strokes before the age of 30. In the 1970s, researchers began to study the effects of lifestyle factors, such as dietary folate and smoking, in people who developed elevated homocysteine levels. During the last two decades, a connection between mild to moderate elevations of homocysteine and heart disease has shown up in some, but not all studies. And organizations like the American Heart Association (AHA) do not currently identify high homocysteine levels as a major risk factor for cardiovascular disease.

If you have not yet been tested, do not be surprised if your doctor is somewhat reluctant to measure your homocysteine level. If other risk factors for heart disease are already present, knowing that your homocysteine level is elevated may not change your treatment. However, according to the AHA, getting screened for homocysteine levels may be useful if you have a personal or family history of cardiovascular disease and do not have the common risk factors, like smoking, high blood pressure, high cholesterol.

What If You Have Elevated Homocysteine Levels?

Homocysteine levels are reduced when intake of folate, vitamin B6, and vitamin B12 is increased. However, studies have not shown that taking these vitamins can prevent or treat cardiovascular disease.

The AHA suggests that people at high risk should make sure they are getting enough folate, vitamin B6, and B12 in their diet. Your doctor can give you specific recommendations about the appropriate dosages for you. Here are the general recommendations for daily intake of folate, vitamin B6, and B12:

  • Folate
    • Males and females aged 14 and older—400 micrograms (mcg)
  • Vitamin B6
    • Males aged 19-50 years—1.3 milligrams (mg)
    • Males aged 51 years and older—1.7 mg
    • Females aged 19-50 years—1.3 mg
    • Females aged 51 years and older—1.5 mg
  • Vitamin B12
    • Males and females aged 14 years and older—2.4 micrograms

Here are a few examples of foods that are high in these vitamins:

  • Folate—citrus fruits, fortified breakfast cereal, vegetables
  • Vitamin B6—fortified breakfast cereal, bananas, baked potatoes with skin
  • Vitamin B12—fortidied breakfast cereal, fish, meat, poultry, and dairy products

If you are concerned about your risk factors for heart disease or if you would like to take supplements, talk to your doctor. The two of you can decide what the best approach would be based on your health and diet.