Seaweed grows up to 150 cm long with prominent midrib. Contains spherical air bladders usually paired on mid-rib. Forms dichotomously branched fronds with smooth margins
Iodized salt contains iodine to prevent deficiency affecting two billion people worldwide. Salt is effective for distributing iodine due to its stability and predictable consumption. Four inorganic compounds are used as iodine sources: potassium, sodium iodate, and sodium iodide
Iodine is a nearly black solid with a glittering crystalline appearance. Above 700°C, it dissociates into iodine atoms. Sublimes to deep violet vapor that irritates the respiratory system. Best weighed in stoppered bottles due to its poisonous nature
Excess iodine inhibits thyroid hormone synthesis through Wolff-Chaikoff effect. Iodopeptides form that temporarily inhibit thyroid peroxidase activity. Effect lasts few days before returning to normal synthesis. Sodium iodine symporter (NIS) downregulation allows normal hormone production
Table salt contains 97-99% sodium chloride (NaCl). Pure NaCl is white, but may have purple or blue tinge from impurities. Sea salt is dull brown or gray, while rock salt varies in color
Trace minerals are essential nutrients needed in small quantities. Most people can get enough through diet, but supplements may be needed. Large amounts of trace minerals can cause adverse effects