Gene + Wrong Foods = Heart Disease
Meat Fats Worsen but Fish Oils Blunt Heart Disease Gene
Dec. 31, 2003 -- Six in 100 Americans carry gene variants that greatly increase their risk of heart disease. But eating the right foods -- and avoiding the wrong ones -- virtually eliminates this risk.
The heart-disease gene types -- variant forms of a normal gene -- are more common among blacks, Asians, Pacific Islanders, and other racial or ethnic groups than among Hispanics and non-Hispanic whites. But some people of all races seem to carry the gene variants.
How bad are the gene variants? They pose a greater risk of heart disease -- based on thickening of arteries -- than smoking, and nearly as great a risk as diabetes. A diet high in arachidonic acid -- mostly found in meat fats -- increases the bad effects of the inherited gene forms. But a diet high in fish oils -- such as those found in salmon, tuna, and mackerel -- blunts these effects.
"These findings suggest that the [heart-protective] effects of [oils] derived from fish might be more prominent in (or perhaps limited to) persons with [the gene variants]," write Raffaele De Caterina, MD, PhD, and Antonella Zampolli, PhD, of Italy's National Research Council. Their commentary -- and the study itself -- appears in the Jan. 1, 2004, issue of The New England Journal of Medicine.
The Origins of Heart Disease
The findings come from a groundbreaking study that pulls back the covers shrouding the mysterious origins of heart disease. James H. Dwyer, PhD, and colleagues at the University of Southern California and UCLA knew that mice lacking the 5-lipoxygenase gene were nearly immune to atherosclerosis, or hardening of the arteries.
To find out whether this gene was important in human disease, they analyzed a racially diverse group of 470 healthy, middle-aged men and women. They found that 6% of these people had a variant form of the gene. Apparently, these gene variants increased a person's 5-lipoxygenase activity.
That's bad, as it turns out. Theoretically, increased 5-lipoxygenase activity would cause cells of the immune system to accumulate inside artery walls. As they accumulated, they cause inflammation and promote the accumulation of cholesterol molecules in the artery wall. Over time, the buildup of artery-clogging plaque leads to heart disease.
And that's what seems to happen. People with the gene variants had much thicker artery walls than those with normal forms of the 5-lipoxygenase gene. Thicker artery walls is a marker for cardiovascular disease.