Vitamins Flashcards

1
Q

Retinoids

A
  • preformed Vitamin A
  • exist in 3 forms that can be interconverted
  • liver, fish oils fortified dairy products, and eggs
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2
Q

Carotenoids

A
  • provitamin A (some converted to Vitamin A)
  • dark green, yellow, orange, red veggies, and fruits
  • yellow-orange pigment in fruits and vegetables
  • alpha, beta carotene and beta cryptoxanthin
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3
Q

Functions of Vitamin A

A
  • growth and development
  • cell differentiation
  • vision
  • immune function
    -dermatology
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4
Q

Immune function Vitamin

A
  • vitamin A
  • protect entry of pathogens into epithelial barriers
  • cellular immunity (function of immune cells)
  • antibody protection
  • increased infection = early symptom of vitamin A deficiency
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5
Q

Cell differentiation vitamin

A
  • vitamin A
  • process of directing stem cells to develop into specialized cells with unique functions
  • retinoids bind to retinoid receptors RXR and RAR which bind to specific DNA sites -> direct cell differentiation
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6
Q

growth and development vitamin

A
  • vitamin A
  • involved in the development of eyes, limbs, cardiovascular system, nervous system, epithelial cells and mucous forming cells
  • lack of vitamin A = birth defects and fetal mortality
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7
Q

Dermatology vitamin

A
  • high doses
  • treatment for psiorasis or acne
  • accutane or retina A
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8
Q

Vision vitamin

A
  • vitamin A
  • retinal is needed in the retina to help convert light energy to nerve impulses in the retina, photosensitive cells contain rhodopsin
  • repeated small losses of retinal, need for replenishment
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9
Q

Non-provitamin A Carotenoid Functions

A
  • antioxidants, protect against macular degeneration, cancers, Cardiovascular disease
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10
Q

Vitamin A deficiency

A
  • rare in NA
  • major problem in developing countries
  • night blindness, irrevesrsible blindness (xerophthalmia), follicular hyperkeratosis (skin)
  • increased risk of disease and death
  • maternal mortality
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11
Q

Vitamin A toxicity

A
  • hypervitaminosis A
  • 3 types (acute, chronic, teratogenic)
  • teratogenic = spontaneous abortion and birth defects
  • liver damage
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12
Q

Vitamin D

A
  • “conditional” vitamin
  • prohormone
  • fatty fish, cod liver oil, fortified dairy products, fortified breakfast cereals
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13
Q

Vitamin D from the Sun

A
  • depends on lots of factors
  • prolonged exposure to sun will not result in toxic amounts bc excess amounts of previtamin are degraded
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14
Q

Vitamin D3 pathway

A
  1. sunlight changes 7-dehydrocholeterol in skin to cholecalciferol (Vitamin D3)
  2. travels to liver and then kidneys, where converted to bioactive form (calcitriol)
  3. synthesis regulated by parathyroid hormone and kidneys
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15
Q

Functions of vitamin D

A
  • calcitriol is the active form
  • maintain blood levels of ca and p (increase absorption of calcium, release ca and p from the bone)
  • regulate immune function
  • regulate the cell cycle
  • reduce risk of chronic diseases (diabetes, hypertension, dementia, cancer)
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16
Q

Vitamin D Deficiency Diseases

A
  • rickets (children, bones fail to calcify normally and bend)
  • osteomalacia (“soft bones”, adults)
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17
Q

Vitamin E

A
  • plant oils, wheat germ, avocado, almonds, peanuts, sunflower seeds
  • main source is alpha-Tocopherol
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18
Q

Vitamin E function

A
  • antioxidant
  • stops the lipid peroxidation of cell membrane and lipoproteins caused by free radicals
  • as vitamin E is “used up” during reaction, must be regenerated by reducing agents such as vitamin C
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19
Q

Vitamin E needs and toxicity

A
  • hemolysis prevention
  • excessive amounts can interfere with vitamin K’s role in blood clotting = hemorrhage
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20
Q

Vitamin E deficiency

A
  • hemolytic anemia
  • preterm infants, smokers, and those with fat malabsorption are the most susceptible
  • immune function impairment and neurological changes
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21
Q

Vitamin K

A
  • menaquinones (k2) = animal sources, synthesized by bacteria in colon, fish oils and meats
    phylloquinones (K1) = main dietary form, green leafy vegetables, broccoli, peas, and green beans, veggie oils, most biologically active
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22
Q

Vitamin K functions

A
  • calcium binding
  • enzymes (carboxylation)
  • synthesis of blood clotting factors (koagulation)
  • metabolism/activation of bone proteins (osteocalcin)
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23
Q

Vitamin K Deficiency

A
  • newborns have a sterile intestinal tract, single dose of vitamin K given at birth, long term antibiotic use, fat malabsorption
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24
Q

Vitamin K Toxicity

A
  • no UL
  • limited storage, more readily excreted
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25
Q

Vitamin B1

A

Thiamin

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26
Q

food sources of thiamin

A

found in small amounts in wide variety of foods

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27
Q

functions of thiamin

A
  • coenzyme form (TPP) *
  • conversion of pyruvate to acetyl CoA (TCA cycle)
  • coenzyme in reactions to form pentoses for DNA and RNA
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28
Q

thiamin deficiency and causes

A

peripheral neuropathy and weakness
alcoholism, poor diet, malnourished
beriberi

29
Q

Beriberi

A
  1. Wet = nervous system and cardiovascular system
  2. Dry and Wernicke Korsakoff syndrome = nervous and muscular system
  3. causes= alc, poor diet, malnourished
30
Q

wernicke korsakoff

A
  • mainly in heavy alcohol users
  • alcohol decreases thiamin absorption, increases thiamin excretion, causes abuser to consume poor diet
  • ataxia (low coordination), visual disturbances, confusion, apathy
  • can occur rapidly
  • emotional disturbances and impaired cognition
  • brain damage in thalamus and hypothalamus
31
Q

B2

A

riboflavin

32
Q

riboflavin functions

A
  • coenzymes (flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD))
  • energy metabolism (TCA cycle, Beta-oxidation, shuttles H atoms to the electron transport system), antioxidant function (glutathione synthesis)
  • activate other B-vitamins
33
Q

ariboflavinosis

A
  • riboflavin deficiency
  • primarily affects the mouth, skin, and red blood cells
  • inflammation of throat, mouth (stomatitis), tongue (glossitis)
  • cracking around the corners of mouth (angular cheilitis)
  • moist, red, scaly skin (seborrheic dermatitis)
34
Q

B3

A

Niacin

35
Q

niacin in foods

A
  • can be synthesized from tryptophan
36
Q

niacin forms and functions

A

nicotinic acid and nicotinamide
coenzymes = nicotinamide dinucleotide (NAD+)
nicotinamide adenine dinucleotide phosphate (NADP+)
- required for catabolism of macros + alc
- redox reactions
- more than 200 reactions

37
Q

niacin toxicity

A
  • “niacin flush”
  • potential health benefits of large amts of nicotinic acid (lower TG and increase HDL)
38
Q

niacin deficiency

A

pellagra
- dermatitis
- diarrhea
- dementia
- death

39
Q

food sources of pantothenic acid

A
  • widespread in foods
  • readily destroyed by freezing, canning, and refining
  • meat, milk, and vegetables
40
Q

B5

A

pantothenic acid

41
Q

functions of pantothenic acid

A
  • component of coenzyme A (CoA) -> formation of AcCoA
  • part of Acyl carrier protein (required to synthesize fats)
42
Q

B6 in foods

A
  • meat fish poultry, fortified cereals, bananas, potatoes
43
Q

B6 functions

A
  • metabolism: PLP coenzyme involved in amino acid metabolism = transamination, glycogenolysis
  • synthesis of compounds: heme (hemoglobin, carries oxygen), histamine, neurotransmitters (serotonin), nucleic acids, ,vitamins (niacin)
  • three forms
44
Q

Vitamin B6 deficiency

A
  • rare
  • microcytic hypochromic anemia
  • hypochromic (less hemoglobin in each RBC)
  • microcytic (smaller size of each RNC) anemia
45
Q

Vitamin B6 upper level

A
  • irreversible nerve damage
  • stored exclusively in muscle tissue
46
Q

Vitamin B7

A

biotin

47
Q

biotin functions

A
  • coenzyme in carboxylase reactions (incorporate Co2 into a substrate)
  • needed for macro metabolism
  • TCA cycle, gluceoneogenesis, FA synthesis, AA breakdown
47
Q

biotin sources

A
  • can synthesize by microbes, widespread in food
48
Q

biotin deficiency

A
  • biotinase enzyme deficiency, excessive consumption of raw eggs
49
Q

egg white injury

A
  • excessive consumption of raw egg white
  • avidin binds to and inactivates biotin
    avidin destroyed by heat
50
Q

B4

A

choline

51
Q

choline

A
  • can be obtained in the diet and synthesized in cells
52
Q

functions of choline

A
  • component of phospholipids *
  • precursor for acetylcholine
  • helps export VLDL from liver
  • helps carnitine move fatty acids into the cells*
53
Q

folate

A

folate in foods and folate supplements

54
Q

folate coenzyme

A
  • DNA synthesis (converts uracil to thymine) *
    -converts B12 to coenzyme form *
  • AA metabolism
  • regeneratees methionine from homocysteine
  • neurotransmitter synthesis
55
Q

folate needs

A

1 DFE (daily folate equivalents) = 1 mcg food folate =0.6 folic acid taken w/food

56
Q

folade deficiency (preg)

A

neural tube defects
- spina bifidia, anecephaly
- day 20~28 post conception = development of spinal cord

57
Q

folate deficiency

A
  • affects cells synthesizing DNA
  • short life span and rapid turnover bc RBCs don’t divide normally and remain large and immature
  • megaloblasts = remain in bone marrow
  • macrocytes = found in bloodstream
  • megaloblastic, (Macrocytic) anemia
58
Q

B12

A

cobalamin

59
Q

b12 sources

A
  • naturally in animal products only!
60
Q

b12 functions

A
  • forms 2 coenzymes (methylcobalamin, 5-deoxyadenosylcobalamin)
    homocysteine -> methionine
  • fatty acid metabolism
61
Q

b12 excess

A
  • stored in liver, providing 2-3 years of storage
62
Q

absorption of vitamin b-12 requires

A

R protein and intrinsic factor

63
Q

b12 deficiency

A
  • macrocytic anemia, neurological changes, elevated plasma homocysteine
64
Q

vitamin c

A

ascorbic acid, not a B vitamin but close

65
Q

food sources of vit c

A
  • vulnerable to heat and oxy
  • used as antioxidant by food manufacturers
  • citrus fruits, peppers, green veg
66
Q

vit c functions

A
  • antioxidant activity
  • collagen synthesis (matrix for bone nad tooth formation)
  • enhances none-heme iron absorption
67
Q

vit c intake

A
  • smoking increases intake
68
Q

vit c deficiency

A
  • scurvy
  • gums bleed easily around teeth
  • capillaries under skin break spontaneously
  • collagen