Minerals PDF 2025

MINERALS Minerals According to Function Nutritionally Essential Transition Metals General Features of Transition Metals Associated directly with proteins via O2, N and S atoms found at side chains of amino acids Associated with porphyrins, corrins or pterins Allows for protection against...

MINERALS Minerals According to Function Nutritionally Essential Transition Metals General Features of Transition Metals Associated directly with proteins via O2, N and S atoms found at side chains of amino acids Associated with porphyrins, corrins or pterins Allows for protection against oxidation, suppression of ROS production, & enhancement of solubility Free transition metals are vulnerable to nonspecific oxidation in cells, hence their levels are extremely low Importance of Iron-Protein Interactions Hemoglobin & myoglobin : pophyrin ring & histidyl residues of the globin polypeptide chain protects Fe+2 from oxidation to Fe+3 – containing methemoglobin Electron transport chain: iron atoms contained within heme groups of cytochromes and Fe-S clusters cycle between ferrous & ferric states Myeloperoxidase: uses heme iron to catalyze condensation of H2O2 with Cl- ions to generate HOCl (hypochlorous acid) DNA replication & repair: enzymes involved contain Fe-S clusters FOOD SOURCES OF IRON Heme Iron From meat, poultry, seafood Non-heme Iron From whole grains, nuts, seeds From animal sources (animals that consume plant food with non-heme iron) From fortified foods ORAL IRON SUPPLEMENTS Iron Preparation Iron compound Elemental Iron Absorbed Iron Unabsorbed Iron (Non-heme) (mg) per tablet (mg) per tablet Ferrous fumarate 320 105 33% 67% Ferrous gluconate 250 30 12% 88% Ferrous sulfate 525 105 20% 80% Ferrous sulfate 200 74 (anhydrous) Ferrous sulfate 200 60 (exsiccated ) ORAL IRON SUPPLEMENTS Iron Preparation Iron compound Elemental Iron Absorbed Iron Unabsorbed Iron (Heme) (mg) per tablet (mg) per tablet Heme iron 10.5 mg 10.5 mg 100% 0% polypeptide INTRAVENOUS IRON PREPARATIONS Intravenous Iron Recommended Maximum Dose Infusion Time Iron Dextran Multiple doses of 100 mg or 1 hour Single Infusion of 1000 mg Iron Sucrose Multiple doses of 200 – 300 mg 15 minutes Ferric Carboxymaltose 1000 mg Single dose 15 minutes Iron Dosing Daily intake vs. Higher ferritin with Same increase in Intermittent daily intake Hemoglobin intake ? 2x a day increases Once daily vs. Once daily better serum hepcidin → Twice a day ? reduced iron absorption Lower dose vs. Same increase in hemoglobin with Higher dose ? fewer side effects https://www.thelancet.com/journals/lanhae/article/PIIS2352- 3026(17)30182-5/abstract Iron Absorption How long does it take to correct anemia? Oral iron uses the body’s normal physiologic mechanism Oral iron takes 4-6 weeks to raise the hemoglobin , 2-3 months to build up iron stores Gastrointestinal side effects: bloating, upset stomach, pain, constipation How long does it take to correct anemia? Advisable to give preoperative IV iron 2-4 weeks before elective surgery A 2023 WHO study of 124 women with anemia showed that participants who received intravenous iron (ferumoxytol) delivered babies with higher cord blood ferritin compared to those who received 325 mg oral ferrous sulfate 2x a day Adverse effects: Fishbane reaction or CARPA (complement-activation-related pseudo allergy Hypophosphatemia (ferric carboxymaltose) https://ashpublications.org/ashclinicalnews/news/7740/Should-Iron-Deficiency- Be-Treated-With-Oral-or-IV Practical Questions Should I still take my oral iron tablets after my IV iron infusion? Is it possible to overdose on iron? https://www.osmosis.org/learn/Hemochromatosis Calcium Majority in bone, teeth and cartilage Extracellular concentration is rigidly controlled Prolonged elevation of intracellular Ca is toxic Phytic acid in cereals binds calcium in intestinal lumen Side effects: constipation, bloating Calcium supplements TYPE OF CALCIUM PREPARATION ELEMENTAL CALCIUM Calcium carbonate 40% Calcium citrate 21% Calcium gluconate 9% Calcium lactate 13% Manganese Mn-containing enzymes are mostly located within mitochondria Isocitrate dehydrogenase (TCA cycle) Glutamate synthetase & arginase (Nitrogen metabolism) Pyruvate carboxylase & PEPCK (Gluconeogenesis) Superoxide dismutase (Mn-SOD) Used in redox reactions, where it cycles between the +2 and +3 oxidation states Zinc Valence shell has full set of electrons and do not adopt alternate oxidation states → not involved in electron transport or even redox reactions unlike Fe and Mn Human body contains 3000 zinc-containing metalloproteins Majority are transcription factors and other DNA- and RNA-binding proteins (with domains called zinc fingers) Also a component of metalloenzymes (e.g., carbonic anhydrase, carboxypeptidase, cytosolic superoxide dismutase, etc.) Zinc in diet Found in highest concentration in animal –source foods Found in nuts, seeds, legumes, whole-grain cereals, fruits & vegetables Absorption inhibited by phytates and calcium Absorption enhanced by protein Impact of zinc supplementation well-studied since 2000 Prevalence not adequately studied due to lack of suitable biomarkers Zinc fingers in TFIIIA (DNA-binding motif) A single amino acid mutation in either of these 2 Zn fingers in the 1,25(OH)2 -D3 receptor protein results in resistance to the action of this hormone and the clinical syndrome of rickets. Cobalt Core component of 5’-deoxyadenosylcobalamin (Vitamin B 12) Cobalt in the center of a tetrapyrrole corrin ring where it acts as a Lewis base to facilitate the transfer of one-carbon, methyl or methylene groups Cobalamins are corrinoids (cobalt-containing compounds) Cobalamin from food binds to haptocorrin in the stomach →dissociates in the duodenum →cobalamin binds to intrinsic factor → recognized & internalized by cubilin receptors Copper Essential component of cytochrome oxidase, dopamine beta hydroxylase, tyrosinase and cytosolic superoxide dismutase Lysyl oxidase uses Cu to generate crosslinking in mature collagen and elastin Absorption can be inhibited by excess levels of Zinc, resulting in potentially lethal anemia