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PHAR300 > 22-Vitamins > Flashcards

22-Vitamins Flashcards

1
Q

What are vitamins

A
  • micronutrients required by the body to carry out a range of normal functions
  • not produced by our bodies, must be derived from food
  • organic compounds essential for normal functioning growth and maintenance of the body
  • needed in small amounts
  • not an energy source
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2
Q

Food preparation and vitamins

A
  • food preparation affects the availability of vitamins
  • vitamins found in all food groups
  • factors that determine amounts: source, sunlight, moisture, growing conditions, plant’s maturity at harvest, packaging and storage
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3
Q

Why we don’t get enough vitamins

A
  • food processing (fast food)
  • dietary or drug interactions
  • genetic (metabolism/absorption/transport)
  • changes in requirements due to physiological state
  • disease (affect metabolism etc)
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4
Q

Provitamins

A
  • inactive forms of vitamin
  • body must change them to active form
  • eg beta carotene
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5
Q

Water vs fat soluble vitamins

A

Water-soluble: B1, B2, B3, B5, B6, B7, B9, B12, C
Fat-soluble: A, D, E, K

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6
Q

Digestion of fat soluble vitamins

A
  • active transport
  • micelles (aggregate of amphipathic lipid molecules) for transport into the intestinal epithelial cells
  • chylomicrons for transport from gut epithelial cells into the lymphatics
  • more toxicity because get stored in fat deposits/lymph nodes etc, not eliminated as quickly
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7
Q

Vitamin A forms

A

Vitamin A : Retinoids
- active forms (retinoids): retinol, retinal, retinoic acid
- precursors (carotenoids)

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8
Q

Mandatory fortification of foods in Canada

A
  • vitamin D in milk
  • folate and niacin in flour
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9
Q

Vit A roles

A

vision (night and day) : precursor of rhodopsin (photo pigment in rods)
immune function: produce immune cells to fight microorganisms
cell production/differentiation: regulates enzyme/blood carrier proteins/structural protein regulation (retinoic acid works with DNA)
Skin: to replace epithelial cells
reproduction: keeps reproductive tracks healthy, maintain fertility (women) and sperm production, embryo development
bones: helps produce bone cells, required for bone remodelling and increase in osteoclasts

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10
Q

Vit A sources

A

+++: beef liver, carrots, sweet potato, chicken liver
++: spinach, mango, cantaloupe, watermelon, broccoli…
+: dried plums, corn flakes, greens beans, milk

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11
Q

Vit A deficiency

A

Xerophtalmia: eye issue
Hyperkeratosis: keratin overgrowth (skin and other epithelial cells)
immune function: vulnerable to infection
- growth retardation, bone deformations, defective teeth, kidney stones

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12
Q

Vit A toxicity

A
  • fatigue, vomiting, abdominal pain, bone/joint pain, loss of appetite, skin disorders, blurred/damaged vision, liver damage
  • Teratogen: causes clef palate and heart abnormalities in babies if consumed during pregnancy (eg acne treatments Retin A and Accutane)
  • skin discolouration
  • increase risk of hip fracture in postmenopausal women, lung cancer, cardiovascular mortality and total mortality
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13
Q

Vitamin D and functions

A
  • sun vitamin
  • activated in liver then kidney first
  • 25(OH)D
  • essential for bone health (increases absorption of calcium and phosphorus in the intestines)
  • helps regulate insulin formation and secretion
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14
Q

Vit D sources

A
  • sunlight
  • fortified foods (milk, cereal)
  • oily fish, egg yolk, liver
  • supplements
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15
Q

Sunshine and vit D

A

Sun -> 7-dehydrocholesterol (skin) absorbs UVB -> converted to previtD3 -> vit D3 (also absorb UVB) -> photo products

Metabolism of VitD3 in liver/kidneys -> 25-hydroxyvitD (major circulating form) -> 1,25-dihydroxyvitD (biologically active form, aka calciferol)

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16
Q

Vit D signalling (receptor)

A
  • active form 1,25(OH)2D3
  • signals through VDR (vit D receptor) in cytoplasm
  • goes to act in the nucleus (with genes)
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17
Q

Vit D deficiency

A
  • children: rickets (bone weakening)
  • adults: osteomalacia (soft bones) and osteoporosis (low bone mass)
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18
Q

Vit D toxicity

A

hypercalcemia —> stones, gastrointestinal symptoms, pee often, psychiatric overtones
(Overall not that toxic, still fortify foods)

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19
Q

Vit D and chemoprevention

A
  • no proven chemoprevention effects
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20
Q

Vit E and forms

A
  • family of eight similar compounds
  • only alpha-tocopherol is considered for human vit E requirement
  • stored mainly in body fat
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21
Q

Vit E functions

A

antioxidant
- protest cell membranes from free radicals (by giving an electron)
- may lower risk of some chronic diseases

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22
Q

Vit E dietary recommendations

A
  • related to the intake of polyunsaturated fatty acids
  • 15mg/day for adults (of alpha tocopherol)
  • 19mg/day for breastfeeding
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23
Q

Vit E sources

A
  • nuts, seeds, veggie oil, whole grain, fruit/veggies, animal products
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24
Q

Vit E deficiency

A
  • occurs with fat malabsorption or rare genetic disorders
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25
Q

Vit E toxicity

A
  • not toxic when orally consumed
  • can interfere with blood clotting
  • lung injury when inhaled
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26
Q

Vit K (K1 and K2) functions

A
  • blood clotting (necessary for thrombin synthesis, so for blood coagulation, promotes synthesis of coagulation factors, Warfarin (anticoagulant) interferes with VitK synthesis)
  • bone health
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27
Q

Vit K sources

A

green veggies, plant oils, intestinal bacteria

28
Q

Vit K deficiency

A
  • rare in healthy people
  • newborn babies at risk
29
Q

Vit K toxicity

A

Rare but can interfere with anticoagulant meds

30
Q

B vitamins

A
  • eight of them
  • primarily act as coenzymes in energy metabolism
31
Q

Thiamin (B1)

A
  • coenzyme in energy metabolism
  • part of the coenzyme thiamin pyrophosphate (TPP)
  • helps break down glucose into energy, make RNA/DNA, power protein, synthesize/regulate NTs
32
Q

Thiamin (B1) food sources

A

Pork, legumes, nuts/seeds, fish/seafood, enriched grain products
- cooking reduces content

33
Q

Thiamin deficiency

A

Beriberi : overall profound muscle weakness and nerve destruction
- milder symptoms: headache, irritable, depression, loss of appetite

34
Q

Thiamin (B1) deficiency

A

None (water soluble)

35
Q

Riboflavin (B2) functions

A
  • coenzyme in energy metabolism
  • supports antioxidants
36
Q

Riboflavin (B2) sources

A

Milk and dairy, enriched grains, eggs
* milk in opaque containers bc riboflavin broken down by light

37
Q

Riboflavin (D2) deficiency

A

Ariboflavinosis: skin disorders, hyperaemia (excess blood), mouth/throat edema, stomatitis, swollen/cracked lips, hair loss, reproductive problems, sore throat, itchy and red
- most common in chronic alcoholism

38
Q

Niacin (B3) functions

A
  • coenzyme in energy metabolism
  • supports fatty acid synthesis
39
Q

Niacin (B3) sources

A
  • can be made from aa tryptophan
  • whole and enriched grains
  • meat, poultry, fish, nuts
40
Q

Niacin (B3) deficiency

A

Pellagra: dermatitis, diarrhea, dementia, death
- can worsen if also B1/B6/iron deficient

41
Q

Medicinal use of niacin (B3)

A
  • high doses used to treat high blood cholesterol
  • side effects: skin flushing, liver damage
42
Q

Pyridoxine (B6) functions

A
  • PLP: coenzyme in protein and aa metabolism, gluconeogenesis (aa —> glucose)
  • produce non essential aas, NTsm hemoglobin
  • helps to lower blood levels of homocysteine
43
Q

B6 sources

A

Meat, fish, poultry, potatoes, bananas, sunflower seeds

44
Q

B6 deficiency

A
  • microcytic hypochromic anemia
  • heart disease (high homocysteine)
  • damages NS —> depression, headaches, confusion, convulsion
45
Q

B6 toxicity

A
  • can cause subtle neurological damage
  • upset stomach, headache, sleepiness, tingling/burning sensation
46
Q

Folate (B9) functions

A
  • coenzyme in DNA synthesis and cell division, and AA metabolism
  • needed for normal red blood cell maturation
  • works with B6 and B12 to help control homocysteine levels
47
Q

Folate (B9) sources

A

Fortified cereals, enriched grains, green leafy vegetables, orange juice, sunflower seeds, legumes

48
Q

Folate (B9) deficiency

A
  • anemia and diarrhea
    • megaloblastic anemia
  • birth defects: spinabifida
  • heart disease
49
Q

Folate (B9) toxicity

A
  • can mask B12 deficiency with folate supplements
  • hypersensitive people may suffer hives or resp problems
50
Q

Cobalamin (B12) functions

A
  • “cobalt containing compounds”
  • needed for normal folate function (DNA and red blood cell synthesis, metabolism of homocysteine)
  • maintains myelin sheath around nerves
51
Q

Cobalamin (B12) functions

A
  • only in animals foods (meats, liver, milk, eggs)
  • some fortified foods
52
Q

Cobalamin (B12) absorption

A

Animal based diets —> (proteases) B12 —> Haptocorrin carrier (oesophagus) —> (proteases) —> intrinsic factor (small intestine) —> gut epithelial cells aka enterocyte —> blood stream —> liver

53
Q

B12 deficiency

A
  • can lead to pernicious anemia —> nerve damage
  • red blood cells can look enlarged (megaloblastic anemia)
54
Q

B12 toxicity

A

No UL set

55
Q

Pantothenic Acid (B5)

A
  • component of coenzyme A
56
Q

Pantothenic acid (B5) sources

A
  • widespread in foods
  • reduced by freezing, canning, refining
57
Q

Pantothenic acid (B5) deficiency and toxicity

A

Rare

58
Q

Biotin (B7) functions

A
  • coenzyme
  • AA metabolism (into glucose)
  • fatty acid synthesis
  • release of energy from fatty acids
  • DNA synthesis
  • rare deficiency/toxicity
59
Q

Biotin (B7) sources

A

Cauliflower, liver, peanuts, cheese
- protein avidin (raw egg whites) binds biotin and prevents absorption

60
Q

Vit C functions

A
  • antioxidant
  • collagen synthesis
  • enhances iron absorption from plant foods
  • makes other essential compounds (eg thyroid hormones, parts of DNA)
61
Q

Vit C sources

A

Fruits: citrus, strawberries, kiwi
Vegetables: broccoli, tomatoes, potatoes, cabbage, leafy greens, peppers

62
Q

Vit C plateau

A
  • plasma vit C achieve steady state when take excess (urinating out the excess since you can’t store it)
  • vit C is water soluble (not protein bound in the blood)
63
Q

Vit C deficiency

A

Scurvy (pale skin, loss of teeth, sunken eyes)

64
Q

Vit C toxicity

A

May cause GI distress in high doses

65
Q

Bogus vitamins examples

A

Hesperidin, pangamic acid, rutin
- marketed but unnecessary

PHAR300 (22 decks)

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