Breakfast cereals are made out of grains like wheat, rice, corn, oats, and bran. They can be served either hot or cold. They contain important nutrients like folate, niacin, thiamine, iron, and protein. Companies that sell breakfast cereals include Kelloggs, Post, and General Mills. Popular varieties of cereals include raisin bran, oatmeal, shredded wheat, puffed rice, and cinnamon toast squares. Kids' cereals like Frosted Flakes and Lucky Charms are also popular.