MCP Lecture 6

Question 1

Folate: number, function, deficiency, susceptible groups

Answer 1

B9

function: precursor of THF (coenzyme used in generating; precursors for DNA and protein synthesis)
deficiency: neural tube defect, macrocytic anemia, hyperhomocysteinemia
susceptible: pregnant women, elderly, alcoholics

Question 2

What does folate deficiency cause?

Answer 2

deficiency inhibits DNA synthesis by decreasing availability of purines and dTMP

Question 3

Cobalamin: number, function, deficiency, susceptible groups

Answer 3

B12

function: coenzyme in methionine synthesis and conversion of methmymalonyl CoA to succinyl CoA
deficiency: pernicious anemia - megaloblastic anemia with demyelination
susceptible: elderly, malabsorption diseases, vegetarians

Question 4

What makes B12 different than other water-soluble vitamins?

Answer 4

stored very effectively in the liver

Question 5

What causes deficiency in B12?

Answer 5

lack of intrinsic factor in the stomach

Question 6

How does intrinsic factor help with absorption of B12?

Answer 6

B12 is released from protein in acidic stomach, binds intrinsic factor, absorbed in distal ileum

Question 7

How does B12 deficiency affect folate?

Answer 7

folate trapped in form that cannot be used for purine and dTMP synthesis

Question 8

What causes megaloblastic anemia?

Answer 8

folate and B12 = megaloblastic anemia - deficiency in nucleotides leads to decrease in DNA and RNA synthesis - cells increase in size without dividing - large immature RBCs released and cannot carry sufficient oxygen

Question 9

What are the macrominerals?

Answer 9

potassium K+
sodium NA+
Chloride Cl-
Calcium Ca2+
Phosphorus P
Sulfur S
Magnesium Mg2+

Question 10

What are the microminerals?

Answer 10

iron
copper
zinc
chromium
iodine
manganese
selenium
molybdenum
fluoride
boron

Question 11

What are potassium, sodium, and chloride critical for?

Answer 11

as electrolytes for fluid homeostasis and in neuromuscular function

Question 12

Calcium: functions, deficiency, susceptible groups

Answer 12

functions: component of bone, signaling, coagulation, muscle contraction, neurotransmission
deficiency: muscle cramps, osteoporosis, rickets
susceptible: children, adult women, elderly

Question 13

What is required for calcium absorption and utilization?

Answer 13

vitamin D

Question 14

What is the most abundant mineral in the body?

Answer 14

calcium

Question 15

What is osteoporosis?

Answer 15

calcium deficiency causing porous bones

Question 16

Magnesium: functions, deficiency, susceptible groups

Answer 16

functions: essential for many enzymes using MgATP (transporters need Mg to recognize ATP), high levels in bone (required for bone formation)
deficiency: weakness, tremors, cardiac arrhythmia (neuromuscular)
susceptible: alcoholics, patients taking diuretics

Question 17

Phosphorus: functions, deficiency, susceptible groups

Answer 17

functions: component of bone, nucleic acids, membrane lipids, required in all energy-producing reactions
deficiency: RARE - rickets, muscle weakness and breakdown, seizure

Question 18

Iron: functions, deficiency, susceptible groups

Answer 18

functions: O2/CO2 transport in hemoglobin, oxidative phosphorylation, cofactor in several nonheme iron proteins and cytochromes
deficiency: microcytic hypochromic anemia, decreased immunity
susceptible: COMMON - children and menstruating women, pregnant, elderly

Question 19

What causes reduction of Fe3+ to Fe2+?

Answer 19

vitamin C

low pH in stomach helps release Fe3+ from ligands and makes it bioavailable

Question 20

What are the two major barriers in iron absorption?

Answer 20

1. release of Fe3+ from food (iron in spinach is tightly chelated and cannot be absorbed)
2. availability of reducing agent to convert Fe3+ to Fe2+

Question 21

What are characteristics of iron-deficient anemia?

Answer 21

microcytic anemia - small, pale RBCs

-less hg produced - RBCs undergo more cell divisions in bone marrow waiting for synthesis

Question 22

What are the symptoms of iron-deficient anemia?

Answer 22

fatigue, pallor, weakness, dizziness

Question 23

What does long term iron toxicity cause?

Answer 23

hemochromatosis - iron overload leading to iron deposits “iron tan” - eventually compromises mitochondrial function leading to lactic acidosis

Question 24

What does acute iron toxicity cause?

Answer 24

overdose in children - most common cause of death due to toxicity (consumption of adult iron supplements)

Question 25

What makes metal microminerals a toxic risk?

Answer 25

chemical properties as redox agents that can cause production of ROS

Question 26

Copper: functions, deficiency, susceptible groups

Answer 26

function: assists iron absorption, cofactor for enzymes required in collagen syntehsis, fatty acid metabolism, and elimination of ROS deficiency: rare - anemia, hypercholesterolemia, fragility of large arteries (bc collagen synthesis), bone demineralization demyelination susceptible: Menkes' syndrome or consuming excessive zinc

Question 27

What is Menkes' disease?

Answer 27

copper-deficiency disorder that comes from inherited mutations in a Cu-transporting ATPase - need to transport into golgi to supply Cu to enzymes (enzymes are secreted without Cu without transporter)

Question 28

What is Wilson's disease?

Answer 28

mutation resulting in copper overload | copper accumulates in liver with severe liver and nervous symptoms

Question 29

Zinc: functions, deficiency, susceptible groups

Answer 29

functions: cofactor for many enzymes and plays a structural role in many proteins (zinc finger) deficiency: poor wound healing, dermatitis, reduced taste acuity, poor growth and impaired sexual development in children susceptible: alcoholics, elderly, people with malabsorption

Question 30

What is the earliest symptom of zinc deficiency?

Answer 30

scaly dermatitis

Question 31

Chromium: functions, deficiency, susceptible groups

Answer 31

function: component of chromodulin - facilitates insulin binding to its receptor deficiency: impaired glucose tolerance susceptible: those with impaired glucose tolerance

Question 32

Iodine: functions, deficiency, source

Answer 32

function: incorporated into triiodothyronine (T3) and thyroxine (T4) - regulates BMR deficiency: goiter, hyperthyroidism/hypothyroidism source: saltwater fish

Question 33

Selenium: functions, deficiency, source

Answer 33

function: component of antioxidant enzymes and deiodinase enzymes deficiency: Keshan disease - cardiomyopathy and cretinism source: selenium content in soil

Question 34

Fluoride

Answer 34

incorporated into bone and teeth - strengthens

Question 35

Boron

Answer 35

involved in bone formation

Question 36

sulfur

Answer 36

component of amino acids

Question 37

Most common vitamin and nutrient deficiencies in children

Answer 37

iron and calcium

Question 38

Most common vitamin and nutrient deficiencies in teenagers

Answer 38

calcium and magnesium, vitamin A, C, B6

Question 39

Most common vitamin and nutrient deficiencies in women

Answer 39

iron, calcium, magnesium, B6, folate, D

Question 40

Most common vitamin and nutrient deficiencies in elderly

Answer 40

B6, B12, D, zinc and chromium | due to compromised absorption

Question 41

Most common vitamin and nutrient deficiencies in alcoholics

Answer 41

especially folate, B6, thiamine