Trace Minerals HN 2024 PDF

Minor Minerals Wayamba University of Sri Lanka Dr. Thilanka Ranathunga  Iron (Fe) in human nutrition Total of about 4 g Two forms of in the body 1. Functional form 2. Non functional form  Iron in food In foods Fe is available in two forms - Haem (Fe 2+) : ferrous –...

Minor Minerals Wayamba University of Sri Lanka Dr. Thilanka Ranathunga  Iron (Fe) in human nutrition Total of about 4 g Two forms of in the body 1. Functional form 2. Non functional form  Iron in food In foods Fe is available in two forms - Haem (Fe 2+) : ferrous – in animals - Nonheme (Fe 3+) : ferric – in plant - Haem iron : porphyrin ring ( a protein)  Absorption Heme Fe absorption (Fe 2+) Pophyrin ring  Heme Fe absorption (Fe 2+) cont Before absorption, Fe must be hydrolyzed from globin portion of hemoglobin or myoglobin Protease in stomach and SI helps in this process Released heme is soluble in SI lumen due to alkaline pH & degradation products of globin Absorption by duodenum Fe bound to porphyrin ring is readily absorbed as metalloporphyrin into the mucosal cell of the SI  Fe2+ absorption cont… Within mucosal cells; Porphyrin ring Potoporphyrin ring Haem oxigenase Released Fe 2+; - used by the mucosal cells - transport through the intestinal cell and then transport to other tissues. In mucosal cell absorption – receptor mediated Non heme Fe absorption (Fe3+) Bound form of Fe in foods enzymatically liberate in SI Once released from food components, nonhaem iron is present as ferric (Fe3+) iron in the stomach Gastric secretion, HCL, pepsin release non haem iron (Fe3+) to lumen Soluble when pH is acidic Some Fe3+ convert to Fe2+ due to acidic pH Vitamin C facilitate this conversion  Factors affecting absorption Enhances Acids, sugars Heme iron Vitamin C Cysteine Alcohol Low Fe stores and high requirement Inhibitors Tannin, oxalic acids, phytates Phosphorus EDTA (Ethylenediaminetetra acetic acid) Ca, Ca3(PO)4, Zn, MN, Ni, Cd  Functions of iron Formulation of hemoglobin (Hb), myoglobin (transport O2 and store O2) - Due to easy oxidation and reduction properties - It can form stable complex with O 2 - Fe bind to phopyrin ring (Haem Fe) Component in myoglobin - It grab O2 that released by Hb - Contain Haem iron with phopyrin ring Regulation of body temperature – by producing E with the help of O2  Functions of iron cont… Muscle functions – by providing energy Maintain immunity - proliferation and maturation of lymphocytes Modulate thyroid functions – component in thyroid peroxidase Brain development and function  Functions of Fe cont… Haem Fe involve in detoxification process and cell respiration Assists transport electrons from H to oxygen Complex of Fe with sulfur, facilitate Fe2+ > Fe3+ Components in enzymes : oxidases, peroxidases Synthesis of DNA : Fe is a co-factor Synthesis of neurotransmitters Tyrosine hydroxylase (Fe is a cofactor) Tyrosine > dopamine > norepinephrine  Assessment of Fe status Serum Hb concentration : not a good indicator - Diurnal variation - At inflammation Fe moves to storage from blood For men - 13.2 to 16.6 g/dL. For women - 11.6 to 15 g/dL. Ferritin concentration - Fe storage - Below 12 – 15 µg/L : Fe stores are going to bbe empty Transferrin/transferrin saturation WHO, 2011  RDA values Males Mg/day 6–9 16 10 - 11 23 12 - 15 30 16 - 18 39 Females 6–9 16 10 - 11 22 12 - 15 36 16 - 18 39 Men – adult 22 Female – adult 33 Pregnant/lactating 33 RDA, SL, 2007  Deficiency Iron deficiency anemia (Body doesn't have enough iron to produce hemoglobin. Hemoglobin is the part of red blood cells that gives blood its red color and enables the red blood cells to carry oxygenated blood throughout your body). (Definition for anemia : is a condition in which the body does not have enough healthy red blood cells)  Reasons for anemia Insufficient supply : malnutrition, vegetarianism Malabsorption : - Gastritis, surgeries, gluten intolerance, crohn’s diseases (mucosa damaged) - Calcium, phosphate, tannin, polyphenols - Medicines : tetracyclines - Excess use of laxatives Increased requirements Blood loss  Symptoms of Fe deficiency Fatigue Irritability Depression Headache Impaired work capacity Susceptibility to infections Hair loss Brittle nails Pallor  Symptoms of Fe deficency anemia Erythropoiesis is affected : low RBC Poor cognitive and motor development Low IQ ability Pale skin Slowed growth and development Poor appetite Abnormally rapid breathing Behavioral problems Frequent infections Sleepy  Risk groups Growing children Pregnant mothers Elderly people Vegetarians People with malaria, hook worm diseases Poorly breast fed babies Women with excess menstrual loss  Food sources Animal origin foods : Meat (red meat), fish, liver Beans Nuts Dried fruits Green leaves : Muringa leaves, Gotukola, Kale, Spinach Soya beans Increased Fe absorption - Fruit after main meals - Mixed with animal origin foods  Excess iron intake Toxic effects begin to occur at doses above 20 mg/kg of elemental iron. Ingestions of more than 60 mg/kg : severe toxicity Black, and bloody stools Diarrhea Liver damage (may occur several days after the ingestion) Metallic taste in mouth Nausea Vomiting blood  Video link https://www.youtube.com/watch?v=KHMHHFhIH Dw  Iodine Concentrated in thyroid gland 15 – 20 mg of Iodide is available in human body 80% of it is in thyroid glands and rest is in blood  Digestion and absorption Dietary iodine ether bound to AA or in free form In the form of iodate (IO3) or iodide (I-) During digestion iodate is reduced to iodide (I-) by glutathione I- rapidly absorbed in GI tract including stomach Small amount of iodinated AA is absorbed Free I- enter in to blood  Functions of iodine Formation of thyroid hormones – regulate growth and development Regulate metabolic rate Development of neurons in fetal life Maintain normal reproductive functions Intellectual development  Thyroid hormone synthesis Iodine trapping Uptake of iodine from capillary to follicular cells of the gland by active transport (against concentration graduate) ATP dependent Na – K pump Synthesis of thyroglobulin By RER in follicular cells Combine with CHO Move to Golgi apparatus This is a substrate of thyroid hormone synthesis Thyroid hormone synthesis cont… Oxygenation of iodide Iodine in follicular cells moved to follicular luman By iodide/chloride transporter Iodine get oxidized Iodination of thyroxin takes place within the thyrogliobuline Monoiodotyrosine > diiodotyrosine > thyroxin Catalyzed by thyroid peroxidase Thyroxin can store in thyroid glands for several months  T3 or T4 circulate as free or bind form Thyroxine an bind with globulin, albumin, prealbumin, albumin  Functions of thyroxin hormone Controlling metabolism Growth Antioxidant function  Measuring iodine status Urinary iodine level Rate of goiter prevalence Serum thyroid stimulating hormone (TSH) Serum thyroglobulin Iodine deficiency  Iodine deficiency Adults : Goiter) - coughing, Hypothyroidism, myxeodema (severe hypothyroidism - tight feeling in throat - changes to voice - difficulty swallowing (dysphagia) - difficulty in breathing  Iodine deficiency cont… Fetus : Abortions, still births, cognition abnormalities, Neonate : Cretinism – severe mental defects, stunted growth, low functions of body organs  Iodine deficiency symptoms Weight gain, fatigue and weakness Thinning hair Dry skin Feeling colder than usual Slowed heart rate Learning and memory difficulties  Food sources Sea foods Iodinated salt and salt added foods Eggs Milk Plant sources : depend on the level of iodine in soil Drinking water RDA  Excess iodine consumption Iodine toxicity is rare and difficult to identify. Caused by overconsumption of supplements containing iodine. The presenting symptoms can vary from mild to severe, including nausea, vomiting, and diarrhea, but can progress to delirium, (mental state in which you are confused, disoriented, and not able to think or remember clearly) Stupor (near-unconsciousness)  Assessment of iodine status Urinary iodine Rate of goiter prevalence TSH (Thyroid stimulating hormones) : normal values are 0.5 to 5.0 mIU/L.  Video link https://www.youtube.com/watch?v=IGovS gF_h4A  Zinc (Zn) Functions Act as metalloenzymes (enzymes that use a metal cation as a cofactor in the enzyme active site) For 100 of enzymes Precursor for insulin formation (enhance proinsulin's solubility) Maintain gut and skin health DNA / RNA synthesis Involve in energy metabolism Other functions : wound healing immune function taste receptor function fatty acid metabolism 41  Food sources for zinc Beef 5.9 Chicken (dark meat) 3.1 Chicken (light meat) 1.0 Wholemeal flour 3.0 White flour 0.9 Oysters 70 42  Zn deficiency Acute : Anorexia Cessation of growth Skin lesions Diarrhea Loss of appetite Birth defect Mental defects Hair loss Abnormal taste and smell Chronic : Stunted growth, lack of sexual development, anaemia 43  Zinc toxicity 300 mg/d – 20 times the US RDA Nausea Vomiting Cramps Diarrhea 44  Assessing Zinc status Plasma : 60–120 µg/dL. Urinary : 20 to 967 mcg/24 hours Hair zinc : 50-250 μg/g 45  Fluoride (F) It is naturally present in many foods and available as a dietary supplement. Fluoride is the ionic form of the element fluorine (F-)  Functions Mineralizes tooth enamel Reverses early decay and remineralizers your tooth enamel. Constituent in teeth enamel : fluorapatte Prevents the growth of cavity-causing bacteria At high levels it has been known to cause dental and skeletal fluorosis (Dental fluorosis is a condition that causes changes in the appearance of tooth enamel)  Deficiency signs Dental caries Poor eye sight Problems related to bones such as osteoporosis Food sources  RDA EFSA recommended an AI of 0.05 mg fluoride/kg b.w. per day from all sources for children and adults, including pregnant and lactating women  Toxicities Dental fluorosis (Excessive fluoride incorporation into dental enamel before the eruption of teeth leads to hypomineralization of the developing teeth, until age of 8 years) (Preventive effect : 1 mg/L, fluoride concentration in drinking water) Respiratory arrest Cardiac depression Vomiting Diarrhea, and salivation. In humans, lethal doses : 40–80 mg/kg b.w.  Assessing the F status Blood plasma : 8 µM (0.15 p.p.m.) Breast milk : (0.005–0.01 ppm) Saliva (0.1 – 1 ppm)  Video links https://www.youtube.com/watch?v=SRic5qTn0t Y https://www.youtube.com/watch?v=suRW4cH mMWs  Selenium Functions Selenium is a constituent of 25 selenoproteins, including thioredoxin reductases, glutathione peroxidases Thyroid hormone metabolism DNA synthesis Apoptosis, DNA respire Antioxidant Reproduction Protection from oxidative damage Protect from infections  Functions cont… Prevent lipid oxidation and platelet aggregation antioxidant and anti-inflammatory activities : prevent Alzheimer’s diseseas  RDAs Age Male Female Pregnancy Lactation Birth to 6 months 15 mcg* 15 mcg* 7–12 months 20 mcg* 20 mcg* 1–3 years 20 mcg 20 mcg 4–8 years 30 mcg 30 mcg 9–13 years 40 mcg 40 mcg 14–18 years 55 mcg 55 mcg 60 mcg 70 mcg 19–50 years 55 mcg 55 mcg 60 mcg 70 mcg 51+ years 55 mcg 55 mcg  Food sources Drinking water Grains Meat Poultry Seafood eggs  Deficiency Keshan disease (cardiac myopathy) Osteoarthritis Exacerbate iodine deficiency  Toxicity Hair loss and nail brittleness or loss Skin rash Nausea Diarrhea Fatigue Irritability Nervous system abnormalities