Evidence Supports Omega-3s Role in Heart Health

CORVALLIS, Ore.New research examining conflicting findings about the benefits of omega-3s and their role in heart health concluded that both fish consumption and omega-3 fatty acid supplementation help prevent heart disease; however, the fatty acids can vary in their effectiveness depending on their sources, according to the study published in the Journal of Lipid Research.

Researchers at the Linus Pauling Institute at Oregon State University sorted through hundreds of clinical trials to determine why many of the studies arrived at differing conclusions. The review concluded both fish consumption and dietary omega-3 fatty acid supplements may still help prevent heart disease; that some fatty acids, from certain sources, are more effective than others; that these compounds may have enormous value for serious health problems other than heart disease; and that the very effectiveness of modern drug therapies for heart disease may be one explanation for the conflicting findings on the benefits of omega-3 fatty acids.

After decades of studying omega-3 fatty acids, its clear that they have value in primary prevention of heart disease," said Donald Jump, author of the analysis, a principal investigator in the Linus Pauling Institute, and professor in the OSU College of Public Health and Human Sciences. Its less clear how much impact fish oils have in preventing further cardiovascular events in people who already have heart disease. The studies done several decades ago showed value even for that patient population, but the more recent studies are less conclusive. We believe that one explanation is the effectiveness of current state-of-the-art treatments now being offered."

He said some of the earliest work that raised interest in omega-3 fatty acids was done in the 1970s with Greenland Inuits, who ate large amounts of fish and were found to have unusually low levels of cardiovascular disease. However, millions of people now at risk for cardiovascular disease take medications, such as statin drugs for high cholesterol; fibrates for high triglycerides; anti-thrombotics to thin their blood; and other drugs with anti-inflammatory or anti-arrhythmia effects. Fish oils can have positive effects on virtually all of these same cardiovascular risk factors, but so can the drugs.

Some of the early studies done on fish oil were prior to so many effective medications being widely available and heavily used," he said. And people often forget that nutrients, like fish oils, are less potent than prescription drugs, and often have their best value when used for extended periods. When so many people in these studies are taking a regimen of medications to address the same issues that fish oil might also affect, its easy to understand why any added benefit from the fish oils is more difficult to detect."

He said a wide body of other research makes it clear that omega-3 fatty acids also have health benefits that go beyond cardiovascular disease. They have been shown to improve visual acuity; improve cognitive function and reduce dementia; reduce inflammation and perhaps some types of cancer, such as colon cancer; and reduce total mortality.

The review also found an important type of omega-3 fatty acid for human health is DHA, which is the predominant omega-3 fatty acid that accumulates in tissues; plan-derived sources of these fatty acids, such as flaxseed oil or chia seeds, have less benefit than those from cold-water fish, because of differences in how the human body processes these nutrients; for individuals unwilling or unable to consume fish or fish-oil supplements, some products made from yeast or algae are high quality; and it is difficult to be certain of the amount of omega-3 fatty acids in farm-raised fish, since these fish require dietary omega-3 supplementation.

We still believe the evidence is strong that the EPA and DHA content in heart tissues and blood is important to health and to the prevention of cardiovascular disease," Jump said. To meet the current recommendations for primary prevention of cardiovascular disease, individuals are advised to consume 200-300 milligrams of combined EPA and DHA per day."