Micronutrients and Minerals I / II Flashcards
What is the daily recommended intake of K+
3500 mg/day
What are some problems associated with excess K+
Deficiency in K+ ?
1- cardiac arrest; K:Na ratio associated with HTN
2- heart arrythmias, muscle weakness and alkalosis (incr pH)
list several important functions of Ca2+
regulation of IC enzyme activities, secretory processes ( nerve conduction/ pancreatic enzy/ milk protein release) , blood clotting, muscle cx, structure/growth of bones and teeth; binds to many proteins- affects protein function; ICF levels ~0.1 mM (10,000 x lower than ECF levels); second messenger; hormone receptor interactions; calmodulin binding; Ca-efflux
Compare promoters (6 major) and inhibitors (6) of Ca2+ uptake/absorption
PROMOTED BY: vit D, gastric acid, lactose, citrate/malate, protein and phosphorous, exercise
INHIBITED BY: oxalic acid, phytic acid, dietary fiber, phosPHATE, steatorrhea (soaps), increased rate of passage
Describe pathology associated with Ca2+ deficiency in adults and children
Rickets (kid); Osteomalacia (adult)
Vit D prevents rickets (poor intestinal absorption/ poor kidney reabsorption of Ca2+ and PO4) ; osteoporosis;
where is phosphorous (P) found in the body; what is it regulated by
found: 85% bones and teeth… 15% elsewhere (nucleic acids)
REGULATED BY VITAMIN D
what are the functions of phosphorous
structure of nucleic acids, phospholipids, activation of enzymes by phosphorylation and ENERGY! ATP ; acid- base balance
what are the dietary sources of phosphorous
animal protein- milk, eggs
processed foods
food additive for pH adjustment to sequester some things like metals
DIETARY EXCESS IS COMMON (Ca:P ratio 1:2)
-promotes Ca excretion
-15 g/kg of diet is upper limit
what are the functions of magnesium
bone stregth/ ATP hydrolysis, enzyme cofactors, binds nucleic acids, muscle relaxation after cx
what is the RDA and food sources for Mg2+
RDA 400 mg/day males RDA ~300 mg/day females
Mg2+ in vegetables, nuts, legumes
intake is well distributed in the US about 30-50% absorb
IC> EC
describe pathology of Mg++ deficiency and toxicity
DEFICIENCY: rare except severe alcoholic (delirium tremens) - has many effects HTN, vascular dz, preeclampsia, osteoporosis
TOXICITY/EXCESS: anaesthetic effects, diarrhea
describe the key roles of sulfur and dietary sources
DIET- sulfate in tissues, and sulfur containing amino acids/ Methionine and Cysteine
ROLE- ley in protein structure (Cys-S-S-Cys) disulfide bonds!!! Key ROLE in transfer groups (Acetyl CoA) things are easily attached and removed from S
true or false
Iron is soluble in the presence of oxygen
FALSE!
Iron is highly toxic and INSOLUBLE in the presence of oxygen
describe how dietary iron is taken up/transported in the blood
Fe3+ consumed and converted into Fe2+ by vitamin C mucosal cells in GI tract absorb Fe2+ and either STORE in form of Ferritin (Fe3+) or export out into the blood with TRANSFERRIN carrier protein
what is the role of zinc
key role in many enzymes - catalysis and structure particularly proteins interacting with DNA (zinc fingers) and thus gene regulation
NOT REDOX REACTIVE!!!
absorbtion of zinc is increased by binding to ___ and _____ nucleotides and decreased by _____
increased by: His and Cys
decreaed by: phyate
______ are key Cys rich proteins that bind many metals at high capacity and are in the liver, stomach, brain and tongue ; and thus these proteins regulate zinc transfer into blood
metallothioneins
where is zinc stored and what is the turnover rate
stored in muscle and bone
turnover SLOW 300 days
describe the symptoms of zinc deficiency
affects almost everything! tissue damage (oxidative stress, apoptosis) immune deficiencies, developmental changes, skin lesions, growth reduction, LATE ONSET SECONDARY SEX CHARACTERISTICS, poor appetite, genetic deficiencies, malabsorption dz- IBD
describe the symptoms of zinc excess
gastric distress, dizziness, nausea, emetic effect at low doses (50 mg) can reduce copper absorption, implicated in Alzheimers dz, can affect cholesterol and lower HDLs
what is the RDA for adults for copper and why is it critical
RDA adult ~0.9 mg/day
critical for cytochrome oxidase- like Fe, Cu is REDOX active and has 2 oxidation states- insoluble
_____ is a prion protein associated with mad cow (bovine spongiform encephalopathy
COPPER PROTEIN!
Describe Cu in relation to Zn and Fe
Excess Zn impairs Cu uptake
Cu promotes/involved in Fe uptake hence Cu deficiency can lead to anemia/leukopenia/neutropenia/ osteoporosis
what are symptoms of excess Cu
weakness, tremors, anorexia, organ damage, nausea, diarrhea
