The AHA recommends a serving of fish two times per week.
Besides being a good source of protein and a food relatively low in the bad type of dietary fat called saturated fat, fish has omega-3 fatty acids -- which have been shown to reduce the risk of heart disease.
Fatty fish such as mackerel, lake trout, herring, sardines, albacore tuna, and salmon, are rich in two kinds of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Foods such as tofu, soybeans, canola, walnuts, flaxseed, and their oils contain alpha-linolenic acid (ALA), which convert to omega-3 in the body. Even though the benefits of ALA are controversial, the AHA still recommends foods containing it as part of a healthy diet.
In addition to their heart-health benefits, there is some evidence that omega-3 fatty acids may also soothe an overactive immune system, says Johnson. Even though this benefit is still being studied, she says there appears to be a link between getting more omega-3s in your diet and reducing allergies, asthma, eczema, and autoimmune disorders.