Micronutrients and Minerals I / II Flashcards

1
Q

What is the daily recommended intake of K+

A

3500 mg/day

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2
Q

What are some problems associated with excess K+

Deficiency in K+ ?

A

1- cardiac arrest; K:Na ratio associated with HTN

2- heart arrythmias, muscle weakness and alkalosis (incr pH)

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3
Q

list several important functions of Ca2+

A

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

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4
Q

Compare promoters (6 major) and inhibitors (6) of Ca2+ uptake/absorption

A

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

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5
Q

Describe pathology associated with Ca2+ deficiency in adults and children

A

Rickets (kid); Osteomalacia (adult)

Vit D prevents rickets (poor intestinal absorption/ poor kidney reabsorption of Ca2+ and PO4) ; osteoporosis;

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6
Q

where is phosphorous (P) found in the body; what is it regulated by

A

found: 85% bones and teeth… 15% elsewhere (nucleic acids)

REGULATED BY VITAMIN D

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7
Q

what are the functions of phosphorous

A

structure of nucleic acids, phospholipids, activation of enzymes by phosphorylation and ENERGY! ATP ; acid- base balance

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8
Q

what are the dietary sources of phosphorous

A

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

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9
Q

what are the functions of magnesium

A

bone stregth/ ATP hydrolysis, enzyme cofactors, binds nucleic acids, muscle relaxation after cx

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10
Q

what is the RDA and food sources for Mg2+

A

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

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11
Q

describe pathology of Mg++ deficiency and toxicity

A

DEFICIENCY: rare except severe alcoholic (delirium tremens) - has many effects HTN, vascular dz, preeclampsia, osteoporosis
TOXICITY/EXCESS: anaesthetic effects, diarrhea

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12
Q

describe the key roles of sulfur and dietary sources

A

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

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13
Q

true or false

Iron is soluble in the presence of oxygen

A

FALSE!

Iron is highly toxic and INSOLUBLE in the presence of oxygen

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14
Q

describe how dietary iron is taken up/transported in the blood

A

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

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15
Q

what is the role of zinc

A

key role in many enzymes - catalysis and structure particularly proteins interacting with DNA (zinc fingers) and thus gene regulation
NOT REDOX REACTIVE!!!

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16
Q

absorbtion of zinc is increased by binding to ___ and _____ nucleotides and decreased by _____

A

increased by: His and Cys

decreaed by: phyate

17
Q

______ 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

A

metallothioneins

18
Q

where is zinc stored and what is the turnover rate

A

stored in muscle and bone

turnover SLOW 300 days

19
Q

describe the symptoms of zinc deficiency

A

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

20
Q

describe the symptoms of zinc excess

A

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

21
Q

what is the RDA for adults for copper and why is it critical

A

RDA adult ~0.9 mg/day

critical for cytochrome oxidase- like Fe, Cu is REDOX active and has 2 oxidation states- insoluble

22
Q

_____ is a prion protein associated with mad cow (bovine spongiform encephalopathy

A

COPPER PROTEIN!

23
Q

Describe Cu in relation to Zn and Fe

A

Excess Zn impairs Cu uptake

Cu promotes/involved in Fe uptake hence Cu deficiency can lead to anemia/leukopenia/neutropenia/ osteoporosis

24
Q

what are symptoms of excess Cu

A

weakness, tremors, anorexia, organ damage, nausea, diarrhea

25
Q

_____ is a rare heretidary dz where the liver does not excrete excess Cu into bile salts as normal and it is released into the blood- onset age 5 y/o causes brain damage involuntary movements and psychosis, liver damage- hepatitis/cirrhosis- gold/green rings in corneas.
_________ is the life long tx or _______ to be curative

A

Wilson’s Dz

Cu-binding drugs or curative tx is liver transplant

26
Q

where is iodine taken up and what is it essential for

A

taken up in gut and concentrates in Thyroid

essential for thyroid hormone production - affecting growth and metabolism

27
Q

how much iodine do we require

A

150 micrograms/day

28
Q

what are the results of iodine deficiency or excess

A

DEFICIENCY: spontaneous abortion, birth defects, irreversible impairment of brain and physical development, GOITER
EXCESS (up to 2 mg/day w/ no effect) chronic excess can disrupt thyroid function

29
Q

what is the function for selenium

A

enzyme cofactor for antioxidant defense, thyroid hormone and insulin function, regulation for cell growth and fertility

30
Q

how much selenium do we need daily?

Deficiency? Excess?

A

adults require 55 ug/day
DEFICIENCY: cardiac failure, liver dz, cancer, atherosclerosis, hair loss, skin changes
EXCESS: peripheral neuropathy, nausea, diarrhea, dermatitis, hair loss, nail deformities

31
Q

whats the formula to estimate total body water

A

TBW (L) = body wt (lbs) / 4