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NBCD > Chapter 9: Fat-soluble Vitamins (Vitamin A) > Flashcards

Chapter 9: Fat-soluble Vitamins (Vitamin A) Flashcards

1
Q

other names

retinoic acid
retinal
retinol
dehydroretinol
anti-infective vitamin

A

vitamin a

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2
Q

vitamin a - chemistry

stable to _____ (ordinary cooking temp), _____, and _____

A

heat, acid, alkali

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3
Q

vitamin a - chemistry

destroyed by _____ and _____ (when become rancid) or light

A

oxidation and destruction

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4
Q

vitamin a - chemistry

exists in 3 forms that are found in animal tissues

A

retinol, retinal, or retinaldehyde and retinoic acid

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5
Q

vitamin a - chemistry

are formed when retinol combines with an organis acid

A

retinyl esters

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6
Q

vitamin a - chemistry

retinyl esters, retinol, and retinal are incovertible; all forms can be converted to retinol acid, a “_____”

A

terminal product

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7
Q

vitamin a - chemistry

are precursors of vitamin a and occur in 2 structural forms

A

carotenes

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8
Q

vitamin a - chemistry

carotenes occur in 2 structural forms that are present in plants (as provitamin, carotenoid precursor)

A

alpha carotene and beta carotene

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9
Q

vitamin a - chemistry

can undergo oxidative cleavage to 2 molecules of retinol

A

beta carotene

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10
Q

vitamin a - chemistry

_____ refers to a biologically active form. found in the animal foods

A

retinol esters

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11
Q

vitamin a - chemistry

_____ is the unit of measure

A

retinol equivalent (re)

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12
Q

vitamin a - chemistry

_____ and united states pharmacopeia units are used to measure vitamin a activity

A

international units (iu)

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13
Q

vitamin a - chemistry

RE = 1 ug retinol (_____ IU)

A

3.33

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14
Q

vitamin a - chemistry

1 RE = _____ beta carotene (10 IU)

A

6 ug

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15
Q

vitamin a - chemistry

1 RE = _____ other carotenoids

A

12 ug

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16
Q

vitamin a - absorption, transport, and utilization

_____ and _____ are the preformed vitamin a (easily absorbed) because it can be metabolized directly into compounds that exert biological effect of vitamin a

A

retinol and retinyl esters

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17
Q

vitamin a - absorption, transport, and utilization

are produced only by plants, and they function as accessory light-gathering pigments that enhance photosynthesis efficiency

A

carotenoids

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18
Q

vitamin a - absorption, transport, and utilization

carotenoids are the common dietary source, however, they are absorbed at much _____ rates

A

slower rates

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19
Q

vitamin a - absorption, transport, and utilization

retinol from food can be absorbed as such by the _____

A

intestinal wall cells

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20
Q

vitamin a - absorption, transport, and utilization

are hydrolyzed to free retinol and an organic acid

A

retinyl esters

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21
Q

vitamin a - absorption, transport, and utilization

absorption if facilitated by

A

bile

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22
Q

vitamin a - absorption, transport, and utilization

_____ carotene are needed to produce the vitamin a activity of 1 ug retinol

A

6 ug

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23
Q

vitamin a - absorption, transport, and utilization

is the predominant retinyl ester in food

A

retinyl palmate

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24
Q

_____% of performed dietary vitamin a is absorbed

A

75%

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25
Q

vitamin a - absorption, transport, and utilization

dietary beta carotene and other carotenoids, _____ is absorbed

26
Q

vitamin a - absorption, transport, and utilization

stored in the _____ (90%) and _____

A

liver; adipose tissue

27
Q

vitamin a - absorption, transport, and utilization

incorporated into the _____ for transport through the _____

A

chylomicrons; lymphatic system

28
Q

vitamin a - absorption, transport, and utilization

cellular RBP and cellular retinoic acid-binding protein attach to retinol and retinoic acid, respectively; transfer to cell nucleus where they can effect gene expression

A

intracellular retinol-binding proteins

29
Q

vitamin a - absorption, transport, and utilization

storage of vitamin a occurs in the liver as _____

A

retinyl ester

30
Q

vitamin a - absorption, transport, and utilization

when in need, it is released from the liver, transported to the blood by forming a complex with a transport protein called _____

31
Q

vitamin a - absorption, transport, and utilization

the conversion of retinol to retinoic acid is _____

A

irreversible

32
Q

Vitamin D - relationship with other nutrients

this vitamin is needed to cleave beta carotene to retinol

33
Q

Vitamin D - relationship with other nutrients

status of this macronutrient affects vitamin A metabolism (the transport and use of the vitamin are dependent on vitamin a-binding proteins)

34
Q

Vitamin D - relationship with other nutrients

deficiency of this micronutrient interferes with vitamin a metabolism thru:
a) reduction in the synthesis of plasma proteins particularly rbp
b) decreased transport of retinol from LIVER stores
*iron is needed to metabolize vitamin a from its liver stores

A

zinc deficiency

35
Q

vitamin a - functions

maintains the cornea and converts the light impulses in the retina

A

normal vision

36
Q

vitamin a - functions

when the light strikes the cornea and reached the retina, the retinal changes from a cis to a trans configuration; _____ is bleached; released by the retina, then goes back to its cis transformation and forms rhodopsin

37
Q

vitamin a - functions

maintenance and repair of healthy _____

A

epithelial cels

38
Q

vitamin a - functions

normal _____ and _____ development

A

skeletal and tooth

39
Q

vitamin a - functions

normal reporduction

40
Q

vitamin a - functions

normal functioning of the _____ ear

A

middle ear

41
Q

vitamin a - functions

prevention of certain types of cancer (anti-cancer effect)

42
Q

vitamin a - deficiency

nyctalopia, bitot’s spots, xerosis, and xeropthalmia

A

eye defects

43
Q

vitamin a - deficiency

impaired growth and development

44
Q

vitamin a - deficiency

depresses immune function

45
Q

vitamin a - deficiency

_____ of tissues

A

keratinization

46
Q

vitamin a - deficiency

cessation of bone growth, painful joints, cracks in teeth, and atrophy of dentin

A

hypovitaminosis a

47
Q

vitamin a - toxicity (high intake)

manifested by headache, dizziness, nausea, dry and itchy skin, hemoglobin losses, cessation of menstruation, induced bleeding

A

hypervitaminosis a

48
Q

vitamin a - toxicity (high intake)

yellow pigmentation of the skin

A

hypercarotenemia

49
Q

vitamin a - toxicity (high intake)

may cause birth defects

A

teratogenic

50
Q

vitamin a - recommended intakes per day

for infants (0-5 months, male and female)

51
Q

vitamin a - recommended intakes per day

for infants (6-11 months) and children (1-9 y/o) male and female

52
Q

vitamin a - recommended intakes per day

for adults (19->70 y/o)

A

males: 700 ugRE
females: 600 ugRE

53
Q

vitamin a - recommended intakes per day

for pregnant

A

600 + 300 ugRE

54
Q

vitamin a - recommended intakes per day

for lactating

A

600 + 400 ugRE

55
Q

in conditions with:
-alcoholism
-diseases of the pancreas
-respiratory illness
-chronic nephritis
-measles
-intestinal parasites
-acute protein deficiency
-prolonged use of neomycin
-sulfate and cortisone
-steatorrhea

A

increase vitamin a intake

56
Q

vitamin a - food sources

green leafy vegetables: kangkong (swamp cabbage), saluyot, camote (sweet potato) tops or leaves, and ampalaya (bitter gourd) leaves

yellow fruits and vegetables (squash, carrots, ripe mango, ampalaya)

A

provitamin a

57
Q

vitamin a - food sources

liver, organ meats, egg yolk, fish liver oils, butter, and fortified margarines

A

preformed vitamin a

58
Q

vitamin a status assessment

commonly used in evaluating vitamin a status

these are relatively constant unless in condition of severe deficiency or excessive intake to the point that vitamin can no longer be complexed for STORAGE IN LIVER

A

serum retinol

59
Q

serum retinol status - criteria (for all ages)

deficient

60
Q

serum retinol status - criteria (for all ages)

acceptable

A

> 30 ug/dL

61
Q

serum retinol status - criteria (for all ages)

marginal

A

10-30 ug/dL

NBCD (89 decks)

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