Cod Liver Oil
Cod liver oil is a compliment and not exactly a food. However, it is impossible to list foods that contain omega-3 and not mention it.
As the name implies, it is an oil extracted from the livers of cod fish. The oil is rich in various nutrients including omega-3 fatty acids, vitamin D and vitamin A. A single tablespoon provides 170% and 453% of the Daily Value, respectively.
This means that taking just a tablespoon of cod liver oil is sufficient provision for three essential nutrients. But it is important to not take more than a tablespoon at a time, as too much vitamin A can be harmful.
Contents of Omega-3: 2,438 mg of DHA and EPA combined per tablespoon.