Seaweed is much more nutrient dense than any land vegetables. It is an excellent source of micronutrients including folate, calcium, magnesium, zinc, iron, and selenium. More importantly, seaweed is a great source of iodine.
DHA and EPA omega-3 fatty acids
Unlike land plants, seaweed contains preformed omega-3 fatty acids DHA and EPA, so seaweed or algae oil can be a reliable source of omega-3 for vegetarians.
Aids with Digestion
Beans can cause gas and stomach upset for many people. This can be easily fixed by adding kombu, a particular kind of seaweed, to the beans when cooking.
Antioxidants
Seaweed contains many antioxidants. As part of a healthy diet, seaweed can help protect against oxidative stresses and prevent chronic diseases such as cancer and digestive problems.
Fiber and Prebiotics
All plants contain fiber, but seaweed also has other odd types of carbohydrates that we lack the digestive enzymes to digest. These include carrageenan, fucan, galactan, and many more. These carbohydrates then become foods for the bacteria.