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Free Fatty Acids May Be Linked to Sudden Cardiac Death in Healthy Men

Aug. 14, 2001 -- About a fifth of the people who die from heart disease are victims of sudden cardiac death, which strikes without warning and often claims victims in the prime of life.

While very lethal, sudden cardiac death doesn't always lead to death of the patient. When it occurs, the heart begins to beat abnormally, causing it to stop pumping blood. Left untreated the patient will die within minutes, but prompt medical attention can also save the patient.

Some conditions such as prior heart attack, diabetes, or a family history of sudden death are known risk factors. But it's still a bit of a mystery, especially when it occurs in otherwise healthy people. Now, French researchers report that fatty acids circulating in the blood may play a role in such sudden cardiac deaths.

Xavier Jouven, MD, PhD, tells WebMD that high levels of these fats, called nonestrified fatty acids or free fatty acids, may be associated with risk of sudden death in middle-aged, healthy men. Jouven, who is a heart researcher at the Hôspital Européen Georges Pompidou in Paris, says that he and his colleagues took blood samples from more than 5,200 French government workers and then followed the men for an average of 22 years.

Very high levels of free fatty acids were associated with "2.5 to three times the risk for sudden cardiac death," says Jouven. He says the men were between 42 and 53 when they were enrolled in the study and the blood tests were done a year after the men entered the study.

The study is published in this week's issue of Circulation: Journal of the American Heart Association.

When people eat fats the body stores those fats in adipose or fat tissue, which then releases the fats into the bloodstream as "free" fatty acids. Several factors, including cigarette smoking, fasting, hyperthyroidism, or heart attack, can trigger the release of free fatty acids and heart experts have long known that high levels of free fatty acids can cause irregular heart beats in people who have heart disease. But Jouven says that his work suggests that high levels of free fatty acids are also dangerous in healthy people.

Alice H. Lichtenstein, DSc, director of the cardiovascular nutrition research program at Tufts University in Boston says that Jouven's study is interesting but very preliminary, and shouldn't cause undue alarm. She points out that the findings are based only on observation, not a clinical trial. "What can be responsibly said is that [free fatty acids] have not been given a lot of attention ... the study suggests that future work should be directed at assessing their potential relationship with disease."

Alexander Leaf, MD, who wrote an editorial that accompanies the Jouven study, says that free fatty acids should not be lumped together as a single entity. The real risk, says Leaf, who is professor of clinical medicine at Harvard Medical School, comes from omega-6 fatty acids, which are found in foods fried in corn, safflower, or sunflower oils.