Heart Disease Risk Factor #4: Homocysteine

A potentially deadly amino acid.

Unhealthy Levels

When Kilmer S. McCully, M.D., first proposed a link between levels of an amino acid called homocysteine and heart disease in 1969, the medical community largely ignored him. But four decades and hundreds of studies later, that community is finally in agreement -- or as close to agreement as it ever comes -- in linking high levels of homocysteine to an increased risk of heart disease, stroke, and peripheral vascular disease (reduced blood flow to the hands and feet).

Homocysteine is formed when the body breaks down dietary protein, especially protein from animal sources. Then B vitamins, particularly folate, B₆, and B₁₂, break down homocysteine so your cells can use it for energy.

But if this breakdown phase fails to occur -- say, if you don't get enough B vitamins -- homocysteine builds up to an unhealthy level. It then damages endothelial cells, preventing the production of nitric oxide. It may also make blood cells stickier, encouraging clotting, which can eventually trigger a stroke or heart attack. In a study of 386 women at the University of Washington in Seattle, those with the most homocysteine in their blood had double the heart attack risk of those with the least. They also had the lowest levels of folate. Further, a 2002 study published in the journal Stroke found that high levels of homocysteine increased the risk of stroke fivefold.

Other research links high levels of homocysteine to the development of dementia or Alzheimer's disease. In one study people with the highest levels of homocysteine at the start of the study were nearly twice as likely to develop dementia.

Thankfully, the homocysteine problem is one of the easiest ones to solve. It's generally as simple as getting more B vitamins. When researchers gave people who underwent angioplasty (a catheter procedure to open blocked blood vessels with a balloon) a combination of the three B vitamins, they found that not only were homocysteine levels lower, but the incidence of repeat blockages dropped, cutting the number of repeat angioplasties in half. And in a Harvard study of 80,000 nurses, those with the highest intake of folate (about 696 micrograms a day) cut their risk of developing heart disease nearly in half.

The older you are, the more you smoke, and the less you move all seem to be tied to higher homocysteine levels. High cholesterol and blood pressure also tend to go hand in hand with high levels of homocysteine. And too much protein in your diet -- think Atkins and the Zone -- can also increase homocysteine levels.

Check with your doctor to find out whether a homocysteine test is appropriate for you; it may be worth taking if you have other known risk factors for heart disease.

A homocysteine level of 5-15 micromoles per liter is normal. Levels above 9 micromoles per liter raises your risk of heart disease.

Quick Tips

• Focus your diet on non-animal proteins, B-vitamin-rich grains, beans, and vegetables. These foods have been shown to reduce homocysteine levels.


• Take a daily multivitamin.


• Exercise regularly.


• Maintain a moderate alcohol intake. An Australian study of 350 obese men and women found that those who drank six 8.5-ounce glasses of red wine per week had blood homocysteine concentrations 17 percent lower than those who didn't consume any alcohol, and 13 percent lower than those who reported primarily drinking beer or spirits.

From Cut Your Cholesterol

 

• Cholesterol
• Heart Disease

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• When your white blood cells work against you.
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• Heart Disease Risk Factor #3: Germs
• The consequences of bacteria and viruses can last well past the immediate symptoms.
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• Heart Disease Risk Factor #5: Metabolic Syndrome and Diabetes
• The possible cause for at least half of all heart attacks.
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• Heart Disease Risk Factor #6: High Blood Pressure
• The symptom-less cause of damaged arteries.
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• Heart Disease Risk Factor #7: Depression
• The power of your mind over your heart.
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• Coffee and Heart Disease
• A good reason to cool your java addiction.
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