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Confused About Omega-3s? Just Eat Fish
The omega-3 fatty acids have been promoted as heart healthy for several years. As far back as 2004, the FDA informed the public that scientific evidence suggested that eating foods rich in omega-3s could lower the risk of heart disease. And while many studies have agreed with this conclusion, some studies have not found any benefits from omega-3s, leaving many people confused about their supposed health benefits.
To try to settle the discrepancies among studies, scientists at the Linus Pauling Institute at Oregon State University reviewed 14 separate trials of omega-3s. Their conclusion? Omega-3s are not that confusing.
According to lead author Donald Jump, “After decades of studying omega-3 fatty acids, it's clear that they have value in primary prevention of heart disease. It's less clear how much impact fish oils have in preventing further cardiovascular events in people who already have heart disease. ”
Jump thinks that one reason some studies show no heart protection from omega-3s is the number of people taking potent heart medications. The effects of these drugs may be much stronger than the benefits of omega-3s and may simply be masking or eliminating omega-3 heart benefits in many studies. This is especially likely in tests of omega-3s in people with existing heart problems, since heart patients are often taking medications such as cholesterol-lowering drugs (statins). Omega-3s are nutrients found in food, not drugs.
The reviewers also point out that omega-3s have health benefits that go beyond the heart. Different studies have linked omega-3 consumption to improved eyesight and cognitive function, as well as to decreases in inflammation and dementia risk.
The earliest studies of omega-3s were done on Greenland Inuits in the 1970s, people who ate large amounts of fish and had unusually low levels of heart disease. Most of today's heart medications did not even exist back then. But times have changed. Today, the best selling drug in the world is a statin and many study participants are statin users.
The review also found that omega-3s from plants, such as flaxseed oil or chia seeds, appear to be less heart healthy than omega-3s from fish because of differences in how the human body processes these foods. In addition, the review found that it is difficult to be certain of the omega-3 content in farm-raised fish, unlike their wild cousins.
The two main sources of omega-3s are fish and dietary supplements. Eating fish seems to be a much surer path to heart health.
A study from the American Journal of Clinical Nutrition found that men who consumed fish at least once a month had a roughly 30% lower risk of heart failure than men who ate less than one serving a month. But when levels of individual omega-3s in the blood were measured, there was no relationship found between heart failure and the level of two omega-3s found most commonly in fish oil/omega-3 supplements, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
It's possible that eating fish may be beneficial for reasons other than its omega-3 content. If fish is replacing less healthy food like cheesesteaks, that alone would make eating it heart healthy. Perhaps the benefits of eating fish come from something other than omega-3s that's in the fish. Right now, no one can say for sure. But they can recommend that people eat more fish.
The American Heart Association recommends that people eat two servings of fatty fish, such as salmon, herring, sardines or albacore tuna, per week. It also suggests that people who already have heart disease may want to discuss taking fish oil supplements with their doctor, though it still recommends eating fish as preferable to taking supplements.
An article on the review appears in the December 2012 issue of the Journal of Lipid Research.
December 21, 2012