Tuna

There is not one individual fish called “tuna” – there are more than a dozen species of tuna worldwide. Many tuna companies, in fact, now track and label their canned tuna products to identify the specific type of tuna, the ocean where it was caught, and more.

Heart Associations recommend eating omega-3-rich fish, such as tuna, twice a week for good health. It's wise, however, to vary what you choose. Because tuna is a source of mercury, you should avoid eating it daily, especially higher-mercury varieties like albacore tuna.

Tuna, for its part, is a source of high-quality protein with almost no fat. It contains all essential amino acids required by the body for growth and maintenance of lean muscle tissue. Canned tuna can be a good source of heart-healthy omega-3 fatty acids, with 150 milligrams or more per four-ounce serving.