There are as many as 21 fish that can be called sardines: The name applies to a number of related small, oily fish, some of which are also called pilchards, and some of which are actually herring. Because sardines are typically smaller than four inches in length, they are especially low in mercury. The young fish eat mostly plankton, which is not a strong source of mercury. As oily fish, they are rich in omega-3 fatty acids, vitamin D, and protein. Since they are typically eaten bones and all, they are also a good source of calcium. In addition, they provide selenium, phosphorus, and iron.Although in some parts of the world sardines are eaten fresh, they are the archetypical canned protein food. Ironically, many canned “sardines” are actually herring, a related fish. Herring have been studied for their high concentration of Coenzyme Q10, a nutrient involved in cell metabolism. Sardines, especially those that are really herring, share this characteristic.Nutritional Facts
Four and three-eighths ounces of skinless, boneless sardines packed in water provides 120 calories, 0 g carbohydrate, 15 g protein, 6 g fat, 0 g dietary fiber, 60 mg calcium, and 2.25 mg iron.