According to the Marine Technology Society, brown seaweeds, such as kelp, contain fucoidan and algin, which have been shown to remove lead, mercury, cadmium, barium, tin and other heavy metals from tissues.20 Seaweeds also help remove radioactive isotopes from the body. Using seaweeds both as a condiment and at least several times a week as a vegetable (so that you consume a half-cup serving) is necessary for chelating action to take place.