Seaweed is macroscopic and multicellular marine algae. Types of algae, like red algae, green algae, and brown algae are also referred to as seaweed. However, kelp and its various types are the most iodine-rich seaweed types. Seaweed is an invariable part of the diet of people belonging to coastal regions like China, Japan, Taiwan, Thailand, Korea, Philippines, Cambodia, Indonesia, Vietnam, Peru, Belize, Chile, Scandinavia, etc.