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Flashcards in vitamins Deck (88)
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1

what does recommended daily allowance (RDA) reflect?

they do not reflect the nutritional needs of individuals but rather provide a tool to compare the contribution of specific food items to the overall diet - what each person needs is an individual things - can actually convert to mg - so really just a unit of measure - approximation of what the average person may need

2

in what kinds of patients do vitamin deficiencies normally occur?

alcohol abusers, elderly patients, patients with small bowel resections, food faddists, and malnourished people in the developing world

3

where can we get water-soluble vitamins in our diets?

all water soluble vitamins except for B12 are in vegetables

4

water-soluble vitamins (summary)

1: most are precursors of coenzymes involved in intermediary metabolism
2: all water soluble vitamins except for vitamin B12 are present in vegetables
3: deficiency of all water soluble vitamins except for vitamin b12 produces clinical symptoms within weeks due to low body stores

5

what are most water-soluble vitamins precursors to?

most are precursors of coenzymes involved in intermediary metabolism

6

how long does it take for symptoms of vitamin deficiency to occur?

deficiency of all water-soluble vitamins except for B12 produces clinical symptoms within weeks due to low body stores

7

vitamin B1 (summary)

thiamine pyrophosphate is a coenzyme for enzymes involved in carbohydrate metabolism, specifically pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase
deficienys causes korsakoff's in alcohol abusers

8

what enzymes is thiamine pyrophosphate (vitamin B1) a coenzyme for?

enzymes involve in carbohydrate metabolism
- pyruvate dehydrogenase
- alpha-ketoglutarate dehydrogenase
- transketolase

9

what is the result of vitamin B1 deficiency?

beriberi-peripheral neuropathy and dilated cardiomyopathy
deficiency results in korsakoff's syndrome in alcohol abusers
administer thiamine with glucose to alcohol abusers
would see impaired eye movements (mystagmus) and ataxia

10

what patient population would you expect to see korsakoff's syndrome in?
what should be administered with thiamine to these patients?

alcohol abusers
administer thiamine with glucose to alcohol abusers

11

what is vitamin B2 (riboflavin) a precursor for?

flavin mononucleotide (FMN) and flavin dinucleotide (FAD) coenzymes

12

what is the result of riboflavin/vitamin B2 deficiency?

fissuring at the angles of the mouth
dermatitis
purple tounge

13

what two compounds can vitamin B3/niacin be found as?

nicotinamide or nicotinic acid

14

what enzymes is vitamin B3/niacin a precursor for?

nicotinaminde adenine dinucleotide (NAD)
nicotinamide adenine dinucleotide phosphate (NADP)

15

why isn't vitamin B3/niacin technically a vitamin?

because humans can synthesize niacin from tryptophan

16

what does vitamin B3/niacin deficiency cause?

pellagra (italian for sour skin)
dermatitis, diarrhea, dementia and death

17

in what types of patients would you expect to see vitamin B3/niacin deficiency?

patients with Hartnup disease (diminshed tryptophan uptake)
patients with carcinoid syndrome (altered tryptophan metabolism)

18

what can vitamin B3/niacin be used for theraputically? in what disorder is this treatment used?

used to lower LDL and VLDL cholesterol in type IIb hyperlipoproteinemia

19

what coenzyme is vitamin B5/pantothenic acid a component of?

coenzyme A

20

what is the result of vitamin B5/pantothenic acid deficiency?

none yet discovered - it's widely available in food and so deficiency syndrome has not been characterized

21

what three molecules does vitamin B6 collectively describe?

pyridoxine, pyridoxal and pyridoxamine

22

what coenzyme is vitamin B6 a precursor for and what does it do?

precursors of pyridoxal phosphate, which catalyzes reactions involving amino acids

23

what drug does vitamin B6 bind to and what is done about this?

it binds to the antituberculosis drug isoniazid
as a result, B6 is routinely perscribed with anti-TB drugs to prevent a deficiency in B6

24

what does a deficiency in vitamin B6 cause?

seizures

25

what is vitamin B7/biotin a coenzyme for?

in carboxylation reactions
in these, it's covalently bound to specific lysine residues of biotin-containing enzymes

26

what is the result of a vitamin B7/biotin deficiency?

dermatitis
glossitis
nausea

27

how would someone acquire a biotin/vitamin B7 deficiency?

by eating greater than 20 raw eggs per day
raw eggs contain a biotin-binding protein called avidin - in the egg whites
apparently people use egg whites as supplements, so could see this in body builders, etc.

28

what molecules is vitamin B9/folate necessary for?

for one-carbon metabolism, including the synthesis of purine and thymidine (and therefore DNA)

29

what does vitamin B9/folate deficiency cause? how would these deficiencies be acquired?

in adults: megaloblastic anemia,
patients taking chemo drugs (methotrexate) - causes shortness of breath due to anemia
pregnant women because fetus is using so much folate
alcohol abusers
in fetuses: neural tube defects -mother didn't get enough folate during first trimester - part of brain or spinal cord can become externalized (spina bifida, anencephaly)

30

how is folate deficiency prevented in our diets?

it has been supplemented in "enriched" foods since 1998 - for people who are alcohol abusers