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Biochem First aid > Nutriton > Flashcards

Nutriton Flashcards

(90 cards)

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0
Q

Which vitamins are fat soluble?

A

A, D, E, K

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1
Q

Which vitamins are more likely to cause toxicity and why?

A

Fat soluble because they distribute into tissue

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2
Q

Who is at risk for fat soluble vitamin deficiencies?

A

Patients with CF, celiac sprue, or who take mineral oil

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3
Q

What is vitamin A?

A

An antioxidant used for normal differentiation of epithelial cells to specialized tissue cells
Prevents squamous metaplasia

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4
Q

What is vitamin A used to treat?

A

AML M3

Measles

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5
Q

What are the signs of deficiency of vitamin A?

A

Night blindness

Dry skin

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6
Q

What are the signs of vitamin A toxicity?

A 
Arthalgia
Fatigue
Headache
Skin changes
Sore throat
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7
Q

What is required before prescribing isoretinoin for acne and why?

A

A negative pregnancy test and a reliable contraception because vitamin a is teratogenic

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8
Q

What foods contain vitamin A?

A

Liver and leafy vegetables

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9
Q

What is vitamin B1?

A

Thiamine pyrophosphate = TPP

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10
Q

What is the function of vitamin B1?

A

Participates in de carboxylation reactions
Alpha-ketoglutarate dehydrogenase
Transketolase
Pyruvate dehydrogenase
All of the above enzymes are required for ATP synthesis

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11
Q

What happens in the deficiency of vit B1?

A

There is impaired glucose breakdown –> can’t make ATP –> depletion

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12
Q

Which organs are affected first by B1 deficiency?

A

Brain and heart ( highly aerobic)

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13
Q

What makes the B1 deficiency worse?

A

Infusion of glucose

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14
Q

What is wernicke’s syndrome?

A

Ataxia + ophthalmoplegia + confusion

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15
Q

What is Korsakoff’s syndrome?

A

Wernicke’s + confabulation, personality change, memory loss

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16
Q

Where is the lesion in wernicke’s-Korsakoff’s?

A

In the medial dorsal nucleus of the thalamus and the mammillary bodies

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17
Q

What is dry beriberi?

A

Polyneuritis

Symmetrical muscle wasting

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18
Q

What is wet beriberi?

A

High output cardiac failure

Edema

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19
Q

Who is at risk for thiamine deficiency?

A

Alcoholics

People who. Are malnourished

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20
Q

What is the function of vitamin B2?

A

It is a cofactors in oxidation and reduction reactions

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21
Q

What is vitamin B2?

A

Riboflavin = FAD and FMN

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22
Q

What are the signs of vitamin B2 deficiency?

A

Cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth)
Corneal vascularization

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23
Q

What is vitamin B3?

A

Niacin = NAD

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24
What does the synthesis of vit B3 require?
Vit B6
25
What is the function of vit B3?
Used in redox reactions
26
Which amino acid is vit B3 derived from?
Tryptophan
27
What are the signs of vit B3 deficiency?
Glossitis | Pellagra
28
What is pellagra?
Vit B3 deficiency : diarrhea, dementia, dermatitis, death
29
What can cause pellagra?
carcinoid syndrome = increased tryptophan metabolism Hartnup disease = decreased tryptophan absorption INH = vit B6 deficiency
30
What are the signs of excess niacin?
Facial flushing
31
What can niacin be used to treat?
Hyperlipidemia
32
What is vit B5?
Pantothenate
33
What is the function of vit B5?
It is a cofactors for acyl transfer (essential component of CoA) Cofactors for fatty acid synthase
34
What are the signs of vit B5 deficiency?
Dermatitis Enteritis Alopecia Adrenal insufficiency
35
What is vitamin B6?
Pyridoxine
36
What is the function of vit B6?
It is a cofactors for transamination decarboxylation reactions and glycogen phosphorylase. Needed for the synthesis of cystathionine, heme, niacin, histamine, NTs (serotonin, epi, norepinephrine, GABA)
37
What are the signs of vit B6 deficiency?
Convulsions Irritability Peripheral neuropathy Sideroblastic anemia
38
What can vit B6 deficiency be induced by?
INH | Oral contraceptives
39
What is vit B7?
Biotin
40
What is the function of biotin?
Cofactor for carboxylation enzymes: Pyruvate carboxylase Acetyl-CoA carboxylase Propionyl-CoA carboxylase
41
What are the signs of biotin defiency?
Dermatitis Alopecia Enteritis
42
What is biotin deficiency caused by?
Antibiotics | Ingestion of raw eggs
43
Which vitamin deficiencies cause alopecia?
Vit A, B5, B7
44
What is vit B9?
Folic acid
45
What is the function of vit B9?
Converted to THF then coenzyme for 1 carbon transfer/methylation reactions Important for synthesis of nitrogenous bases in DNA and RNA
46
What food is vit B9 found in?
Leafy green vegetables
47
How long do folate reserves last?
Couple of months
48
What are the signs of float deficiency?
Macrocytic, megaloblastic anemia
49
What are the causes of folate deficiency?
``` Alcoholism Pregnancy (increased need) Phenytoin Sulfonamides MTX ```
50
What is the most common vitamin deficiency in the US?
Folate
51
What is B12?
Cobalamin
52
What is the function of vit B12?
Cofactors for homocysteine methyltransferase and methylmalonyl-CoA mutase
53
What are the signs of B12 deficiency?
``` Macrocytic, megaloblastic anemia Peripheral neuropathy Ataxia/falls Spasticity Dementia Hyper segmented PMNs ```
54
What are the levels of homocysteine and methylmalonic acid in B12 deficiency?
Both are high
55
What foods have B12 in them?
Animal products
56
What can cause B12 deficiency?
``` Strict vegan diet Sickle cell anemia (increased need) Malabsorption (sprue, enteritis, Diphyllobothrium latum) Pernicious anemia Gastric bypass surgery Chron's disease Resection of the terminal ileum ```
57
Where is folic acid absorbed in the gut?
Jejunum
58
Where is B12 absorbed in the gut?
Ileum
59
What is SAM?
s-adenosyl methionine = ATP + methionine
60
What is the function of SAM?
Transfers methyl units
61
What is SAM required for?
The conversion of NE to epi
62
What is the regeneration of methionine/SAM dependent on?
Folate and B12
63
What is vit C?
Antioxidant that facilitates iron absorption by keeping in iron reduced state. Necessary for hydroxylation of proline and lysine in collagen synthesis. And dopamine b-hydroxylase (converting dopamine to NE) Ascorbic acid
64
What does deficiency of vitamin C cause?
Scurvy - swollen gums, bruising, hemarthrosis, anemia, poor wound healing Weakened immune response
65
What are the signs of excess vitamin C?
N/v, diarrhea, fatigue, sleep problems | Predisposes to iron toxicity in people with hemochromatosis or transfusions
66
What is vit D2 and D3?
D2- Ergocalciferol consumed from plants | D3 - cholecalciferol - from milk and sun
67
What is the storage form of vit D?
25-OH D3
68
What is the active form of vitamin D?
1,25-(OH)2 = calcitriol
69
What is the function of vit D?
Increases intestinal absorption of calcium and phosphate | Increases bone mineralization
70
What does vit D deficiency cause?
Rickets - children, bone pain and deformity Osteomalacia - adults, bone pain and muscle weakness Hypocalcemic tetany
71
What are the signs of excess vit D?
Hypercalcemia Hypercalciuria Loss of appetite Stupor
72
In what condition is excess vit D seen?
Sarcoidosis from increased activation of vit D by the macrophages
73
What is vit E?
An antioxidant that protects RBCs from free radical damage
74
What are the signs of vit E deficiency?
Increased fragility of erythrocytes (hemolytic anemia) Muscle weakness Posterior column and spinocerebellar tract demyelination (ataxia, falls, paresthesia)
75
Who makes B12?
Microorganisms
76
Where does vit K come from?
Synthesized by intestinal flora
77
What is the function of vitamin K?
Catalyzes gamma carboxylation of glutamic acid residues on factor II, VII, IX, X, C, S
78
What enzyme is necessary for the reduction of vitamin K?
Epoxied reductase
79
What drug antagonizes vit K?
Warfarin blocks epoxied reductase
80
What are the sx of vit K deficiency?
Neonatal hemorrhage with increased PT and PTT time, but normal bleeding time
81
What are the causes of vit K deficiency?
New born Malabsorption (CF, sprue) Antibiotics
82
What is the function of Zinc?
Important for function of enzymes and zinc fingers of the transcription factor motif for altering DNA expression
83
What are the signs of zinc deficiency?
``` Delayed wound healing Hypogonadism Decreased adult hair Dysgeusia(distortion of taste) Anosmia Increased risk for alcoholic cirrhosis ```
84
What are the two enzymes involved in alcohol metabolism?
Alcohol dehydrogenase in the cytosol | Acetaldehyde dehydrogenase in the mitochondria
85
What is the limiting agent in alcohol metabolism?
NAD - needed to convert ethanol to acetaldehyde and acetaldehyde to acetate
86
What are the pharmacokinetics by which alcohol dehydrogenase works?
Operates via zero order kinetics
87
Why do you get hypoglycemia and fatty acid synthesis after alcohol ingestion?
Because NAD is converted to NADH during the metabolism of alcohol. You have so much NADH that the liver starts using it to convert pyruvate to lactate and oxaloacetate to malate. This inhibits gluconeogenesis and stimulates fatty acid synthesis
88
Why do you get acidosis after alcohol ingestion?
From overproduction of lactate | Ketone body production from depletion of oxaloacetate
89
Why do you get increased FA synthesis after alcohol ingestion?
From increased NADPH from the breakdown of excess malate

Biochem First aid (3 decks)

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