Minor Minerals Flashcards

Question

In iron-deficiency anemia, the red blood cells are usually classified as: ``` Answers: 1. Similar to B12 deficiency anemia 2. Microcytic and hypochromic 3. Microcytic and hyperchromic ``` 4. Normocytic and hypochromic 5. Megaloblastic and hypochromic

Answer 1

Microcytic and hypochromic

Answer 2

Correct3. | Low circulating T4; increased secretion of TSH; hyperplasia and hypertrophy of thyroid tissue

Answer 3

Correct Cofactor in alcohol metabolism

Answer 4

Superoxide dismutase, cerruloplasmin

Answer 5

Iron - hemoglobin, respiration, immune, cognitive development, energy metabolism -fatigue anemia Zinc - immune function, growth and development, stabilize cell membranes and body proteins - dermatitis diarrhea, decreased apatite and taste, infection poor growth and development Copper - aids iron mtabolism, antioxidant enzymes, involved conective tissue metabolism - anemia , low white blood cell count , poor growth Manganese - cofactor several enzymes, involved carb metabolism and antioxidant protector - poor growth, skeletal abnormalities Iodine - thyroid hormone component, basal metabolims growth and development- goiter, cretinism Selenium- part antioxidant system as glutathione peridoxase activates thyroid hormones - Keshan disease reduced thyroid hormone Chromium- enhance insulin action - glucose intolerance Fluride- increase resistance tooth enamel - dental risk Molybdenum- cofactor several enzyme- unknown

Answer 6

Iron - hemoglobin, respiration, immune, cognitive development, energy metabolism -fatigue anemia RISK - children, pregnant Meat, seafood, eggs, fortified

Answer 7

the rest are rare iodine - if not fortified selenium if not in soil

Answer 8

Heme iron (ferrous iron): Fe2 +, found in hemoglobin and myoglobin of animal fleshNon-heme iron (ferric iron): Fe3 +, iron found in plant foods, grains, supplements (supplements can also come in the ferrous form), some minor amounts in meat Iron cookware can also contribute to iron intake (important source for populations in developing countries, or when dietary iron sources are scarce) In humans: Fe2+ for absorption, Fe3+ for transport

Answer 9

Bioavailability Plants sources (in Fe3+ ) contain factors interfering with iron absorption, even in iron enriched products: Phytic acid, oxalic acid, polyphenols, excess fibre Meat, fish, HCl and ascorbic acid enhance non-heme iron absorption when consumed together => conversion to Fe2 + for adequate absorption

Answer 10

Toxicity • Anorexia, nausea, vomiting, intestinal cramps, diarrhea • Reduced Cu bioavailability (metallothionein); competition with Fe absorption • Impaired immune function

Answer 11

ZINC REQUIREMENTS Deficiency • Anorexia (= loss of appetite) • Dermatitis, impaired vitamins A, D and thyroid hormone function, alopecia, poor wound healing • Delayed growth, poor development in children • Decreased taste • Decreased immune function Note: alcohol excess intake increases Zn requirement for its metabolism (alcohol dehydrogenase) + increases excretion via urine

Answer 12

1) Zn is a cofactor to over 300 enzymes - From every enzyme class (oxidoreductases, hydrolases, lyases, isomerases, transferases, and ligases) - Zn Binds amino acid residues and stabilizes the enzyme’s tertiary structure, and/or - Zn Participates in the reaction at the catalytic site - Zn-dependent enzymes are involved in: o Protein, carbohydrate, lipid, nucleic acid and alcohol metabolism o Growth and development o Immune response o Antioxidant defence o Neurological function o Reproductive function 2- Zinc is a cofactor to transcription factors • Over 2,000 transcription factors require zinc • The binding of zinc to transcription factors results in a conformational change that resembles a “finger” • Zinc fingers interact with metal response elements (MREs) located in the promoter region of genes to enhance or repress transcription • The nuclear receptors that bind estrogens, thyroid hormones, vitamin A and vitamin D are examples of zinc finger proteins • => Decreased thyroid hormone and BMR observed in zinc-restricted diets nc

Answer 13

Alcohol dehydrogenase: alcohol • Converts alcohol to acetaldehyde; also converts retinol to retinal • Contains 4 zinc atoms per enzyme – 2 involved in catalytic activity, 2 stabilise protein structure Carboxypeptidases A and B: protein digestion • Secreted by pancreas and involved in protein digestion • Enzymatic activity decreases with zinc deficiency => poor protein digestion Polyglutamate conjugase: folate digestion • Catalyses the removal of glutamic acids from folate => poor zinc status can diminish folate absorption Superoxide-dismutase: antioxidant • Catalyses the removal of superoxide radicals: 2O2• + 2 H+ → H2O2 + O2 • SOD1 and SOD3 are zinc and copper dependent: Zn plays a structural role, Cu is catalytic Matrix metalloproteinases: wound healing • Degrade components of the extracellular matrix to allow for remodelling of extracellular matrix proteins and tissue repair • Zinc located at the catalytic site where the substrate binds

Answer 14

Deficiency Iodine deficiency disorders (IDD) = goiter and neurological cretinism Goiter: when T4 level drops, increased TSH secreted, thyroid enlarges to trap more iodine; Low T3 =>slowed metabolism Neurological cretinism: irreversible mental retardation, loss of hearing & speech abilities, short stature, neurological disorder, muscle spasticity in the future child. Occurs when the mother is deficient in iodine during pregnancy, breastfeeding, or when deficiency is maintained during early childhoodHypothyroidism in adults: Effects of hypothyroidism are more subtle in the brains of adults than children: low educability, apathy, and reduced work productivity. Other symptoms: fatigue, weight gain, cold intolerance, constipation. WHO’s mission was to eradicating iodine deficiency in the decade to 2020 (fortified salt, iodine oil, & fortified milk interventions)

Answer 15

Toxicity • Nausea, vomiting, stomach irritation, impaired absorption of other minerals • Hemochromatosis: genetic disorder where the “mucosal block” (ferritin storage) does not function adequately • Ferroportin is not regulated: despite high iron level, more is exported to the blood and taken to tissues • Iron deposits and overload in liver, heart • If not managed, leads to liver cirrhosis, heart failure, elevated oxidative stress markers • Management includes: regular blood "letting", dietary advice to reduce high iron containing foods, chelation therapy

Answer 16

Deficiency • Iron-deficiency anemia = microcytic hypochromic anemia (decreased hemoglobin); decreased hematocrit (% blood volume containing RBCs), decreased serum ferritin*, transferrin receptors number on cells increases • Symptoms: shortness of breath, fatigue with usual tasks, compromised immunity, depression, spoon -shaped nails • Most common minor mineral deficiency worldwide • At risk: premature infants, children, child-bearing age women, vegetarians & vegans, regular blood donors, gastric ulceration • If during growth and development: impaired cognitive development that may be irreversible • Symptoms may be few initially when diet is changed (e.g. limiting iron sources) => iron stores are being used up

Answer 17

1- Oxygen delivery Hemoglobin: Found in red blood cells, transports O2 and CO2, 4 x Fe-containing heme groups which bind 1 oxygen each Myoglobin: found in skeletal and cardiac muscle, stores O2 , 1 x Fe-containing heme group binds 1 oxygen 2- Oxidation – reduction reactions => Can be harmful in high concentration, as iron forms free radical compounds Fe2+ + H2O2 Fe3+ + OH- + •OH (hydroxyl radical) 3- Immune function required for lymphocytes and natural killer cells production 4- Iron-containing metalloenzymes What are some examples you have come across? 5- Energy metabolism Involved in the first steps of the CAC and as cofactors of cytochromes in the electron transport chain 6- Alcohol and drug metabolism Hepatic cytochrome p450 detoxification system enzymes and catalase require iron as co-factors 7- Neurotransmitter synthesis Cofactor in enzymes involved in synthesis of dopamine, epinephrine, norepinephrine, serotonin

Answer 18

Small Intestine Fe2+ DMT-1 and HCP-1 (1st enter the) Brush Boarder Ferrireductase converts fe3+ to Fe2+ (reductase REdUE 3 to 2) Mucosal block = Ferritin: prevents excess absorption binds and stores iron in enterocytes (and other tissues) Ferroportin= transport iron out (trnasPORTIN) Hepcidin regulates (regulates everything only one not F) Convert fe2+ to fe3+ (oxidise) Hephaestin in enterocytes and ceruloplasmin in the blood Transported as Fe3+ bound to Transferrin (TRANSFER after transPORT) uptake endocytosis lysosomes release iron and transferren is recycled

Answer 19

Absorption • As Fe2+ in small intestine, mediated by carrier proteins (DMT-1 and HCP-1) • Efficiency depends on body’s iron status (average 18%; range 14 - 40%) • HCl in stomach and vitamin C enhance absorption by conversion of Fe3+ to Fe2+ form Ferrireductase: enzyme in the brush-border also converts Fe3+ to Fe2+ Excessive intake of calcium, zinc, phosphorus, manganese may chelate iron and interfere with its absorption ``` Storage/carrier proteins in the enterocyte • Ferritin: binds and stores iron in enterocytes (and other tissues) • Iron does not enter bloodstream if body’s iron stores are high • Ferritin prevents excess absorption => “mucosal block” Ferroportin: transports iron out of enterocytes when supplies are low for release into the blood • Hepcidin: regulates how much iron is released into the circulation Ferroxidase enzymes: Hephaestin in enterocytes and ceruloplasmin in the blood (both copper-dependent metalloenzymes) convert Fe2+ to Fe3+ • Transported as Fe3+ bound to transferrin • In tissues cells: uptake by endocytosis; lysosomes release the iron, and transferrin is recycled ```

Minor Minerals Flashcards

(43 cards)