The iodine content of most food sources is low and can be affected by soil iodine concentrations, irrigation water concentration, and that of fertilizers. Most foods provide 3-75 µg iodine per serving. Seafood has higher concentrations of iodine since marine animals can concentrate iodine from seawater . Seaweed contains 16-2984 µg per serving. The other iodine-rich foodstuffs are cod (99 µg per serving), dairy products (56 µg), grain products (45 µg), and eggs (24 µg) .