minerals – Chemistry – Flashcards
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| what are major minerals? |
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| major minerals - needed in amounts >100mg/day. Ca, P, Na, Cl, Mg, S |
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| what are trace minerals? |
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| trace minerals - needed in amounts <100 mg/day. Fe, Zn, Cu, Mn, Fl, Cr, I, Se, Mo |
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| are minerals changed during digestion/use? destroyed by light, heat, or alkalinity? |
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| no&no |
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| define bioavailability |
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| bioavailability refers to how much of that we ingest that ends up in the bloodstream |
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| what kinds of things can change the absorption rate of minerals? |
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| the body's need, other fiber & minerals can hamper other's absorption. some compounds such as phytic acid and oxalate bind some minerals |
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| what is the est. daily need for Na? what does the AHA recommend? what is the recommendation for CHF pts? |
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| 500 mg. AHA recommends and CHF pts should be on 2.4 g |
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| what is the typical daily Na+ intake with the american diet? what % if this is naturally occuring? |
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| 6 g 10% of which is naturally occuring |
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| what organs does excess Na in our diets affect? |
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| the kidneys are under a lot of pressure to excrete excess Na |
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| are Na deficiencies common? when might they happen? |
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| Na deficiency is not common, they would only happen due to a disease or rx |
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| why is serum Na not a good assessment of body Na levels? |
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| Na is a mostly extracellular ion |
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| what are the functions of Na? |
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| regulates fluid balance, nerve impluse transmission, muscle function, regulates blood pH, allows absorption of glucose into small intestine, (thus low salt diet for diabetics) |
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| what is hyponatremia? why does it occur? what does it cause? |
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| low blood Na levels. it usually occurs due to increase excretion of Na, (diarrhea, vomiting, intense prolonged sweating). it causes dehydration b/c water follows salt, (hypovalemia: water loss). this can cause edema from fluid movement into cells -> can lead to neurological problems in the elderly |
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| what is hyperatremia? what can it lead to? |
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| high Na blood level. this can lead to increase in blood pressure, (arterial stretching activates Ca channels causing smooth muscle to contract and shorten the arterial diameter=HTN) |
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| what might hypernatramia be due to? |
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| it can be due to CHF/kidney disease. w/CHF the contractility of the heart is decreased = ejection fraction is decreased. this can lead to kidney failure due to lower perfusion, which leads to lower capacity for excretion of wastes, (renin angiotensin system is upregulated) |
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| why would reading K levels for blood where hemolysis has occured be inaccurate? |
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| K is an intracellular electrolyte |
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| what foods have high levels of K? |
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| fruits and vegetables |
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| how does processing food affect Na, K levels? |
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| processing food tends to lower K and raise Na levels |
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| what charge ion is important in membrane potential regulation? |
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| cations, such as Na, K, Cl |
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| what does lack of K cause? what might cause this? |
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| cramps. diuretics can cause these w/out a KCl rx |
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| how does K deficiency cause increased blood pressure? |
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| lack of K causes muscle contraction which causes peripheral resistance in arteries |
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| what is an example of the nervous system being tightly regulated in terms of K? |
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| the CNS will maintain adequate K levels even if blood and muscle levels decrease |
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| how do high K levels affect Na and blood pressure? |
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| high K levels decreases Na levels and blood pressure |
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| what is hypokalemia? what can cause it? |
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| low K. vomiting, diarrhea, bulimia, (cardiac rhythms can be disrupted by changes in ion levels), alcoholism, (decreased K intake/increase excretion). laxative abuse, (they target cells in large intestine where K/Mg is reabsorbed). cardiac rhythms can be disrupted by changes in ion levels. diabetics in ketoacidosis can be infused with insulin, which increases K influx into the cells |
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| what is hyperkalemia? what might cause it? |
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| high K. rare, usually due to increased intake, important to monitor pts on diuretics. normal blood level: 3.5-5.5, heart attack: >7 |
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| is Cl a extra or intracellular electrolyte? |
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| extracellular |
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| how does Cl maintain a neutral environment in the blood? |
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| Cl shift, it moves in and out of the RBCs |
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| where are lower Cl levels found in the CV system? higher? |
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| Cl is lower in arterial blood, higher in venous |
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| what function does Cl perform in the stomach? |
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| combines with H+ to form HCl |
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| when Cl is absorbed by the large intestine, what happens? |
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| pH is raised, in conjunction with the kidneys/bicarb system |
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| what can cause hypochloremia? what does it do in the body? |
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| frequent vomiting as well as sudden fright can cause low chloride levels. hypochloremia can lead to metabolic alkalosis, (high blood pH), and resp alkalosis which can result in abnormal cardiac rhythm/decreased flow to the brain. xanax, alcohol, GABA and benzos all have depressing effects on the CNS but increasing cellular Cl influx, causing excitation of inhibitory neurons |
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| what is hydroxyapatite? |
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| a complex of Ca and P which binds to collagen protein matrix formed by osteoblasts for new bone growth. |
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| how much of body weight is made up by Ca? how much of that is in bone? |
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| 1-2% 99% |
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| when is mineralization of bone most active? |
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| during linear growth |
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| how is bone strengthened? who is this important for especially? |
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| repeated stress, (weight bearing exercise) caucasian women have lower rates of Ca absorption, so they are encouraged to do this |
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| how does Ca help with hormonal gene regulation? |
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| Ca acts as a second messenger and helps with phosphorylation of gene expression enzymes |
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| is Ca needed for muscle contraction? |
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| yes |
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| how does lack of Ca affect coagulation of blood? |
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| its presence triggers clotting |
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| what is currently being attempted regarding the DV of Ca being 1000 mg/day? |
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| most people do not receive enough, esp adolescents and senior citizens, (system of bone mineralization is slower), people on diets who cut out dairy are also at risk |
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| why are men at less of a risk for osteoporosis? |
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| they have more muscle mass creating more tension which stimulates osteoblasts |
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| what does PTH overproduction cause? |
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| demineralization of bone, possible hypercalcemia |
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| what is calcium absorption dependent on? |
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| vitamin D which increases the transcription of Ca binding protein, enhancing the absorption of Ca into the intestine/system |
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| do phytates decrease Ca absorption? |
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| yes |
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| why would pts in dialysis be at a higher risk for hypercalcemia? |
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| phosphorous is usually high in pts on dialysis, and phosphorous stimulates higher PTH levels which in turn releases more Ca from the bone, raising Ca levels |
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| how can high levels of supplemental phosphorous and magnesium decrease Ca absorption? |
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| phosphorous likes to bind to Ca, should be at a 1:2 ratio |
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| how does a decrease in estrogen levels affect Ca? |
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| low estrogen can decrease Ca absorption, (direct affect on vit D) |
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| when are Ca supplements absorbed most efficiently? |
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| between meals |
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| what % of mineral intake is usually absorbed? how can this be increased? what is this dependent upon? |
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| usually about 35-40% is absorbed. absorption is increased by stomach acid which chelates minerals to AAs, increasing their solubility. (antacids can affect this) |
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| what does excessive Ca interfere with? |
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| absorption of other minerals such as Zn, Mg, and I |
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| why is phosphorous important? |
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| component of ATP, DNA, RNA, phospholipids, phosphorylation of enzymes via kinases, contributes to bone mass |
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| where is phosphorous found? |
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| it is abundant in fruits, dairy products, (if people eat a high amount of bone marrow, they are at risk of high P which binds Ca) |
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| what enhances absorption of phosphorous along with Ca? |
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| calcitriol, (vit D) |
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| what enhances urinary excretion of P? |
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| PTH |
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| what is hypophosphatemia? what is is due to? what can happen long term? |
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| low P levels in the blood, due to decreased absorption or increased excretion, (due to increased PTH), vit D deficicency, or overuse of P-binding antacids, (common in dialysis pts). long term: osteomalacia can result |
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| what is hyperphosphotemia? |
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| high P levels, can be due to kidney disease, under active PTH, excessive vit D supplements, overuse of P-binding laxatives. high P w/low Ca increases risk for bone loss |
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| is there an accurate way to tell how much Mg is in the body? why? |
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| not at the moment, b/c half the body's stores are in bone & half in soft tissue |
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| is it likely there is a sub-clinical Mg deficiency in the US diet? |
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| yes, combined with increased excretion |
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| what is the first tx for pts with HTN? |
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| MG2+ |
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| what are some functions of Mg in the body? |
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| coenzyme to DNA, protein synth, glycolysis, and ATP production. it stabilizes ATP, enhances insulin action, potentiates the action of some peptide hormones |
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| how does Mg affect muscles? |
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| it is a muscle relaxant |
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| when pts are on loop diuretics, what are 2 important supplements? |
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| Mg, vit B for muscle soreness, psychosis |
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| is Mg a safe supplement? what does its toxicity cause? |
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| yes, toxicity will just cause diarrhea |
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| what are some foods containing Mg? |
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| hard water, plants and refined foods |
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| what is the normal absorption rater for Mg? what are 2 things which can decrease its absorption rate? |
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| normal absorption is 50%, high fiber and high Ca can affect bioavailability |
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| what accompanies hypomagnesemia? |
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| low levels of Mg in the blood usually accompanies lower levels of K and P, (b/c they are all intracellular) |
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| what can cause hypomagnesemia? |
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| kidney disease, alcoholics, (muscle cramps and bleeding problems - liver is where coagulation materials are made), diuretic use, and prolonged diarrhea |
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| can Mg help with tension headaches and restless leg syndrome? |
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| yes, (restless leg syndrome is associated with increased PTH levels) |
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| what are the 2 states of iron? |
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| ferrous 2+ and ferric 3+ |
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| what does iron function as? is it a trace mineral? |
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| iron is a trace mineral, which transports O2 on HB and myoglobin. it functions as a cofactor in enzymatic rxns, NT synthesis, and brain development |
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| what other minerals does the absorption of iron affect? |
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| Mg, Zn, and Ca |
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| what is too much Fe associated with? how does Vit C play into this? |
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| heart disease and Ca. Vit C can increase levels of iron absorption |
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| what transfers Fe? stores it? how can this information be used to determine iron levels in the body? |
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| transferrin transfers Fe, and ferritin stores it in the liver. levels of transferrin correlate with iron binding capacity, (receptor # deptends on need) |
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| when does loss of iron occur? |
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| Fe loss occurs in people with colitis or GI infections, due to intestinal cells sloughing off |
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| how does stomach acid help with iron absorption? |
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| stomach acid solubilizes Fe and converts it to the ferrous state for absorption |
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| what is the most bioavailable iron? does anything affect this? |
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| heme iron. Vit C enhances heme iron. steak blood/liver contains high levels of heme iron |
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| what can happen with dialysis pts in terms of Fe? |
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| dialysis pts can develop atherosclerosis due to increased Fe |
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| what can malabsorption of iron be due to? |
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| high phytic acid in diet, polyphenols (tannins) in tea and coffee, soy, oxalates, (spinach), fiber, Ca, Zn, (these minerals use the same transport so increases in one can negatively affect others) |
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| where does most iron for new RBCs come from? |
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| breakdown of old RBCs |
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| how is iron lost during bowel movements? |
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| some intestinal cells store Fe, and they are sloughed off during bowel movements |
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| why do women have a higher iron requirement? who else requires iron supplementation? |
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| they have a lower muscle mass and loose some Fe through menstruation. atheletes also require Fe supplementation |
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| what is the most common nutritional deficiency in the world? for whom? |
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| Fe, in children 6-24 mo |
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| what can Fe deficiency be due to? |
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| diet, esp consuming binders or compounds that decrease/block absorption of Fe. it can also be due to hemorraging/acute infection - anything that causes RBC turnover |
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| what is a sign of Fe deficiency? |
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| decreased serum ferritin |
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| how can inadequate protein intake in malnourished children affect iron storage? |
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| pts may not be able to make enough transcripts for storage |
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| what is hemochromatosis? who is at risk for this? |
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| chronic iron overload, caused by a genetic defect. african american males are at a higher risk, due to higher myoglobin |
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| what is zinc important for? |
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| cell replication, maintenance of the immune system, DNA rep, sense of smell/taste, and apoptosis |
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| does zinc deficiency have severe consequences? |
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| yes |
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| what things can negatively affect zinc absorption? |
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| high Ca, Fe, (same trasport mech), also phytic acids, fiber |
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| how is excess Zn prevented from entering the blood? |
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| metallothionine binds Zn in the intestinal cells |
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| how does Zn travel in the bloodstream? |
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| Zn is bound to albumin, helps prevent it from being filtered in the kidney, though escape of large molecules such as glucose, (such as the case is in diabetes), can increase the excretion of smaller ones such as Zn |
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| why do deficiencies occur more easily with Zn? |
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| it is not stored in high amounts |
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| what is Zn necessary for? |
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| maintenance of hormones, particularly testosterone |
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| why does laxative use decrease Zn levels so fast? |
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| digestive uses carry high amounts of Zn |
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| what can happen with Zn deficiency? |
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| Zn deficiency can lead to hypogonadism, hair loss, skin lesions, growth retardation, impaired taste |
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| what can Zn be used to treat? |
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| zinc can be used to treat wilson's disease, where hyperabsorption of Cu occurs, (Zn saturates the transport mech for Cu) |
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| what is Zn deficiency linked with? |
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| heart disease, obesity, higher estradiol levels, (what testosterone converts to w/out Zn, also speeds up replication of Ca cells |
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| can alchol consumption cause Zn deficiency? |
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| yes |
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| what can cause excessive Zn? |
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| loss of libido, muscle spasms, menstrual cycle problems, sciatica. metallic taste |
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| is Zn a trace metal? |
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| yes |
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| what is selenium, (a trace mineral), a component of that has antioxidant properties? |
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| selenium is a component of gluathione peroxidase, which fights oxidation found in things like polyunsaturated fatty acids which oxidize in heat |
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| what is iodine, (a trace mineral), a component of? what if there is a deficiency of I? |
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| thyroid hormones, T3+4, I deficiency can lead to short stature and mental retardation |
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| what is hypothyroidism? how is it related to iodine levels? |
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| the thyroid enlarges when iodine is scarce to more efficiently trap iodine |
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| what happens with I/T3-4 deficiency? |
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| premature graying, cardiomegaly, (increased heart size), heart failure, mental retardation in children, decreased sharpness of mind |
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| why are TSH levels high in a pt with hypothyroidism? |
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| the tissue is not responding, more is produced, (conversely low TSH correlates with hyperthyroidism) |
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| what is chromium, (a trace mineral), important for? |
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| glucose homeostasis. chromium is a part of a molecule called glucose tolerance factor, it potentiates the action of insulin, (glucophage acts similarly) -increases lean body mass |
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| how low should NaCl intake be lowered for a pt with a hx of HTN and CHF? |
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| <2 g/day |
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| why would Mg be recommended for a pt with a hx of HTN and CHF? |
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| Mg will decrease contractility of smooth muscle around arteries, essentially dialating them |
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| why would increased K be recommended for a pt with a hx of HTN and CHF? |
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| K regulates blood pressure |
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| why would red yeast rice be recommended for a pt with a hx of HTN and CHF? |
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| this particular yeast produces a compound that is statin, (HMG CoA reductase inhibitor) |
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| why would niacin be recommended for a pt with a hx of HTN and CHF? |
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| niacin can lower LDLs |
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| why would B complex vitamins be recommended for a pt with a hx of HTN and CHF? |
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| these will support and increase the rate of metabolism, maintain healthy skin and muscle tone, enhance immune and nervous system function, promote cell growth and division—including that of the red blood cells that help prevent anemia |
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| why green leafy vegetables not be recommended for a pt with a hx of HTN and CHF? |
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| this is high in vitamin K, if the pt has coagulation tendencies, this will make it worse |
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| why restricted fluid intake be recommended for a pt with a hx of HTN and CHF? |
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| this will reduce the amount of work the heart has to do |
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| why would omega 3 FAs/vit E recommended for a pt with a hx of HTN and CHF on metoprolol and ASA? |
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| metoprolol can upregulate cholesterol synthesis in the liver, vitE can thin the blood, blocks absorption of vit K. omega 3 FA are precursors for prostaglandins, which are anti-inflammatory |
