Study Finds Fish Won't Prevent Heart Failure
WEDNESDAY Sept. 30, 2009 -- While eating fish does appear to help protect against heart attacks and other cardiovascular disease, a new Dutch study finds it doesn't seem to guard against the development of heart failure.
Heart failure is a degenerative condition, but with the right treatment and lifestyle people are living longer with it. In fact, some 5.7 million Americans are living with heart failure, and 670,000 new cases are diagnosed each year, according to the American Heart Association.
"We examined whether the intake of fish and its omega-3 fatty acids could protect against the development of heart failure in people who had no history of coronary heart disease," said lead researcher J. Marianne Geleijnse, an assistant professor of epidemiology at Wageningen University. "However, we found no association except for a possible protective effect of omega-3 fatty acids against heart failure in a subgroup with diabetes."
There is strong evidence for a general cardioprotective effect of omega-3 fatty acids from fish, although the underlying mechanisms are not yet clear, Geleijnse said.
The report is published in the October issue of the European Journal of Heart Failure.
For the study, Geleijnse's team collected data on 5,299 men and women who participated in the Rotterdam Study. The researchers wanted to see if the omega-3 fatty acids in fish could protect people from developing heart failure as they appear to protect people from other types of heart trouble.
Over almost 12 years of follow-up, the researchers found that 669 people developed heart failure.
Geleijnse's group found that eating fish rich in omega-3 fatty acids was not significantly related to developing heart failure in either men or women. Both types of these acids the researchers looked at (EPA and DHA) have been linked to reduced blood pressure, heart rate, arrhythmias and triglyceride levels, all of which are associated with risk of heart attack and heart disease.
However, there did seem to be a small benefit in the reduction of heart failure among diabetics who ate the most fish, Geleijnse noted. "It is worthwhile to further examine whether dietary intake of omega-3 fatty acids could reduce the risk of heart failure in diabetics," she said.
"Fish intake may not influence risk of heart failure, but there is strong evidence that it protects against myocardial infarction, sudden cardiac death and stroke," Geleijnse stated. "Therefore, it is wise to consume fish twice per week, in particular fatty fish like salmon, herring and mackerel."
Dr. Gregg C. Fonarow, a professor of cardiology at the David Geffen School of Medicine at the University of California, Los Angeles, said that "heart failure results in substantial morbidity, mortality and health-care expenditures. Finding effective strategies to prevent heart failure is a very high priority."
Clinical trials have shown that supplementation with certain formulations of omega-3 fatty acids reduce the risk of recurrent cardiovascular disease and produce modest improvements in survival in patients with established heart failure, Fonarow said.
"A prior observational study suggested that, among older adults in the U.S., dietary consumption of fish was associated with a lower incidence of heart failure," he said. "This new observational study conducted in the Netherlands did not find that self-reported dietary consumption of fish at higher levels was associated with a lower risk of heart failure," Fonarow explained.
"Only prospective randomized placebo-controlled clinical trials will be able to definitively establish whether or not omega-3 fatty acid supplementation reduces the risk of new-onset heart failure," Fonarow said. "Such studies are now ongoing."
Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, added that "we have abundant evidence that fish consumption is good for health overall and cardiovascular health in particular. This study doesn't change that."
Even in this study, the trend for fish intake was favorable with slightly less heart failure in those consuming the most, he said. "We should expect that the incremental contribution of fish to health is modest. Fish can contribute to your health, and that of your heart, but do so most reliably in the context of healthful living," Katz said.
Posted: September 2009