Overview Definition micronutrients required in the diet for necessary cellular functions Major examples iron (Fe) copper (Cu) zinc (Zn) chromium (Cr) fluoride (F) iodide (I) selenium (Se) Others V, Mo, Mn, Co, and Ni Function part of metalloenzyme login to view 5 more bullets part of metal-containing enzyme login to view 5 more bullets Oxidative stress organometallic side reactions that damage tissue login to view 5 more bullets reactions happen frequently, but the body can defend itself with anti-oxidants login to view 1 more bullet examples of oxidative stress damage login to view 3 more bullets Iron Source diet recycled from destroyed erythrocytes Forms ferrous iron (Fe2+) login to view 3 more bullets ferric iron (Fe3+) login to view 2 more bullets Absorption Fe-containing compounds are solubilized in low stomach pH Fe3+ is reduced to Fe2+ (requires vitamin C) in intestine so it can cross gut lumen ferroportin brings Fe3+ into bloodstream from enterocytes login to view 3 more bullets Storage must be immediately used or stored to prevent: login to view 4 more bullets site login to view 3 more bullets stored as ferritin (Fe3+) hemosiderin binds excess Fe3+ to prevent from entering the blood Transport carried as Fe3+ by transferrin in the blood login to view 5 more bullets ferroxidase (aka ceruloplasmin) oxidizes Fe2+ to Fe3+ for transport and storage login to view 1 more bullet Excretion no cellular mechanism for iron excretion lost from blood loss and removal of skin cells and other epithelial cells Toxicity beyond the sequestration capacity of ferritin causes oxidative stress Disorders in iron handling hereditary hemochromacytosis Copper Role human metabolism like other metals, free copper is potentially toxic by donating electrons login to view 1 more bullet copper is a cofactor for many metalloproteins login to view 3 more bullets Transport albumin and ceruloplasmin carry copper in the blood login to view 1 more bullet metallothionein is a carrier of copper, zinc, and many other metals login to view 2 more bullets Excretion excess copper removed in the bile login to view 1 more bullet Deficiency causes login to view 3 more bullets symptoms login to view 8 more bullets Disorders in copper handling Wilson's disease Menke’s disease login to view 12 more bullets Zinc Function hundreds of enzymes require zinc login to view 4 more bullets Transport metallothionein carries zinc login to view 1 more bullet Deficiency causes login to view 3 more bullets symptoms login to view 10 more bullets Chromium Deficiency causes login to view 1 more bullet symptoms login to view 3 more bullets Flouride Source mainly fluoridated water Deficiency plays a role in bone and teeth formation/strength login to view 2 more bullets Iodine Source mainly iodized salt Deficiency plays a role in synthesis of thyroid hormone login to view 2 more bullets Selenium Deficiency causes login to view 1 more bullet symptoms login to view 4 more bullets