Dietary guidelines recommend that we keep our total fat intake below 35 percent of calories. And more important, most of those fats should come from the polyunsaturated and monounsaturated fatty acids available in fish, as well as nuts and certain vegetable oils. In particular, the long-chain fatty acids—eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in the oil of deep-water fish (mackerel, herring, salmon, sardines, and tuna, for example)—seem to help protect your heart, improve your mind, reduce your risk of diabetes, ward off cancer, and perhaps serve as an adjuvant therapy in ulcerative colitis.
Fishing for Heart Health
Consumption of EPA and DHA has been strongly linked with reducing the risk of cardiovascular disease (CVD). Evidence from multiple large-scale epidemiologic studies and randomized controlled clinical trials suggests that EPA and DHA in the form of dietary fish or fish oil supplements lower triglycerides, reduce the risk of sudden cardiac death and heart attack, and slow the buildup of atherosclerotic plaques.
Research on the benefits of omega 3s on heart health is so convincing that the American Heart Association (AHA) advises people without known coronary heart disease (CHD) to consume at least two fatty fish meals a week. For people with CHD, the AHA recommends a serving of fatty fish daily, which translates to about one gram a day of omega 3s. Even individuals who have elevated triglycerides may need 2 to 4 grams of EPA and DHA per day in a supplement.
In 2000, the Food and Drug Administration (FDA) began allowing a qualified health claim linking dietary supplements containing EPA and DHA omega-3 fatty acids with a reduced risk of CHD. The claim states: “Consumption of omega-3 fatty acids may reduce the risk of coronary heart disease. FDA evaluated the data and determined that, although there is scientific evidence supporting the claim, the evidence is not conclusive.”
The FDA recommends that intake of EPA and DHA not exceed 3 grams per day (with no more than 2 grams coming from supplements) and in September 2004 announced that it will allow a qualified health claim for EPA and DHA omega-3 fatty acids on conventional foods.
The benefits of omega 3s may also extend to people with diabetes who are at very high risk of heart disease. In the Nurses’ Health Study, women who ate fish five or more times per week reduced the risk of developing heart disease by as much as 64 percent, compared to those who ate fish less than once a month. Heart disease risk was reduced by about 30 percent in women who ate fish one to three times a month, and 36 percent in those who ate fish two to four times a week.
Why are omega 3s so heart healthy? The answer lies partly in their anti-inflammatory activities. Harvard University researchers recently linked the consumption of omega-3 fatty acids with lower levels of markers of inflammation, including C-reactive protein (CRP).
The anti-inflammatory effects of omega-3 fatty acids may also help reduce the risk of stroke. In a recent study of more than 4,700 elderly individuals (aged 65 to 98) over 12 years of follow-up, researchers determined that consumption of baked or broiled fish one to four times a week reduced the risk of ischemic stroke by 27 percent.
Another disorder characterized by markers of inflammation that may benefit from omega 3s is Crohn’s disease (CD). In a recent randomized, placebo-controlled clinical study, dietary supplementation with fish oil plus antioxidants (vitamins A, C, and E and selenium) was linked with significantly lower production of inflammatory markers.