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Omega-3s: Not So Heart Healthy?
A new study casts doubt on the conventional wisdom of eating fish to help prevent heart disease. Those omega-3 fatty acids so prevalent in many types of fish may not lessen the risk of developing heart disease after all, at least for men.
Researchers in Denmark tracked the dietary, exercise, and lifestyle habits of 3,277 men and women who were free of heart disease at the beginning of the study. Besides looking at the effect of omega-3 fatty acids, the researchers studied the effects of two other fatty acids, linoleic acid and alpha-linoleic acid on the risk of heart disease.
Over a period of 23 years 471 of the study participants developed ischemic heart disease, the type caused by the build-up of plaques in the coronary arteries. The women who reported consuming the most omega-3 fatty acids seemed to benefit from the nutrient with a 38 percent lower risk of heart disease than women who consumed much less.
Male participants did not seem to benefit from omega-3s at all. No association was found between the risk of heart disease and the intake of either alpha-linolenic acid of linoleic acid on either gender.
There is doubt about the broad value of the results of this study given the problem of studying the eating habits of just one country as well as the study's relatively small size. Because of these limitations, the results do not really prove anything. There could be an unknown factor that goes along with a diet rich in fish that played into the results. The study also did not look at whether or not fatty acids could be beneficial in the prevention of cardiovascular events such as stroke or heart attack in those with established heart disease.
In 2004 the FDA issued a "qualified health claim" for omega-3 fatty acids in which they stated that there is "supportive but not conclusive" evidence that omega-3s can reduce the risk of heart disease. The statement issued by the FDA said "scientific evidence indicates that these fatty acids may be beneficial in reducing CHD."
The American Heart Association recommends eating two servings of fish per week and even suggests fish oil supplements for some people. Until there is much more research into this issue, people should continue to make fish a regular part of their diet. If nothing else, fish remains a good replacement for other meats that are high in saturated fat, a known risk factor for heart disease.
The study is published in the October issue of the American Journal of Clinical Nutrition.
October 4, 2011