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!!!