The protein food group includes not only animal sources such as beef, poultry, pork, fish, and eggs but also many plant sources such as legumes, nuts, and seeds. The protein food group is a good source of protein, iron, B vitamins (such as niacin, thiamin, riboflavin, vitamin B6, vitamin B12), zinc, and magnesium. Many types of fish are also a good source of the omega-3 fatty acids EPA and DHA. Plant sources of protein, such as legumes, are often good sources of fiber.