Fish has achieved health food status due to research that shows eating fish lowers the risk of heart disease. Public health agencies have recommended eating fish for several years. But new research continues to support additional links between diets that include fish and various measures of heart health.
While fish is a healthy source of lean protein, it is the omega-3 fatty acid content of fish, particularly fatty fish like salmon and tuna that is thought to help protect against heart disease. The key to lowering your risk of heart disease with fish seems to be eating enough fish each week to raise your blood levels of omega-3 fatty acids.
A recent study compared the omega-3 fatty acids in the blood of Japanese men living in Japan, Japanese men living in the U.S. and American men living in the U.S. Japanese men living in Japan had twice the blood level of omega-3 fatty acids and the lowest rate of heart disease as the other two groups. In addition, higher blood levels of omega-3 fatty acids in the Japanese men improved at least one measure of atherosclerosis. This and other studies provide ample evidence that it may be omega-3 fatty acids from fish and seafood that are keeping the rates of heart disease in Japan so low compared with other countries.
The omega-3 fatty acids are richest in fish with the most fat. The American Heart Association recommends that healthy people eat fish at least two times per week and to include fish like salmon, albacore tuna, mackerel, lake trout, herring and sardines. These fatty fish are rich in two of the long chain omega-3 fatty acids associated with lower rates of heart disease.
There are many ways that omega-3 fatty acids might help the heart. They are thought to reduce platelet aggregation and make the blood thinner, reduce triglyceride levels, and prevent arrhythmia. Supplementing the diet with fish or fish oil seems to greatly reduce the chances of having a heart attack. Supplementation is even being considered as a common intervention for people at a very high risk of having a heart attack.
But eating other types of fish can be heart healthy as well. Fish is low in saturated fat and eating fish can help keep levels of dietary saturated fat low and lower your risk of heart disease. And while fatty fish are highest in omega-3 fats, most fish have some of the heart these heart healthy fats. The levels of omega-3 fatty acids also vary with the diet fed to the fish. So, farm raised fish can have a very different fatty acid profile than wild fish of the same species. Because of this variability, a good approach is to eat a different types of fish and to consistently include fatty fish.
A new study compared fatty fish and lean fish for their affects on heart disease risk. While heart disease patients who were placed on a diet that included fatty fish several times per week had higher blood levels of omega-3 fatty acids at the end of the study, blood pressure actually decreased in the patients who ate lean fish several times per week. The effect of eating fish on blood pressure may be due to some other component of fish than omega-3 fatty acids.
What's the best way to gain the heart health benefit of omega-3 fatty acids from fish? Eating fatty fish is the best way. Many research studies support the heart health benefit of eating fish. But if you can't eat fish, don't like fish, or can't eat enough to meet recommendations, supplementing with omega-3 fatty acids or fish oil is a good alternative. Intervention studies have proven some benefit of taking these supplements to reduce the risk of heart disease. Talk with your health care provider if you are considering taking a dietary supplement.