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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
Vit E toxicity
- not toxic when orally consumed - can interfere with blood clotting - lung injury when inhaled
26
Vit K (K1 and K2) functions
- blood clotting (necessary for thrombin synthesis, so for blood coagulation, promotes synthesis of coagulation factors, Warfarin (anticoagulant) interferes with VitK synthesis) - bone health
27
Vit K sources
green veggies, plant oils, intestinal bacteria
28
Vit K deficiency
- rare in healthy people - newborn babies at risk
29
Vit K toxicity
Rare but can interfere with anticoagulant meds
30
B vitamins
- eight of them - primarily act as coenzymes in energy metabolism
31
Thiamin (B1)
- 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
Thiamin (B1) food sources
Pork, legumes, nuts/seeds, fish/seafood, enriched grain products - cooking reduces content
33
Thiamin deficiency
**Beriberi** : overall profound muscle weakness and nerve destruction - milder symptoms: headache, irritable, depression, loss of appetite
34
Thiamin (B1) deficiency
None (water soluble)
35
Riboflavin (B2) functions
- coenzyme in energy metabolism - supports antioxidants
36
Riboflavin (B2) sources
Milk and dairy, enriched grains, eggs * milk in opaque containers bc riboflavin broken down by light
37
Riboflavin (D2) deficiency
**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
Niacin (B3) functions
- coenzyme in energy metabolism - supports fatty acid synthesis
39
Niacin (B3) sources
- can be made from aa tryptophan - whole and enriched grains - meat, poultry, fish, nuts
40
Niacin (B3) deficiency
**Pellagra**: dermatitis, diarrhea, dementia, death - can worsen if also B1/B6/iron deficient
41
Medicinal use of niacin (B3)
- high doses used to treat high blood cholesterol - side effects: skin flushing, liver damage
42
Pyridoxine (B6) functions
- PLP: coenzyme in protein and aa metabolism, gluconeogenesis (aa —> glucose) - produce non essential aas, NTsm hemoglobin - helps to lower blood levels of homocysteine
43
B6 sources
Meat, fish, poultry, potatoes, bananas, sunflower seeds
44
B6 deficiency
- microcytic hypochromic anemia - heart disease (high homocysteine) - damages NS —> depression, headaches, confusion, convulsion
45
B6 toxicity
- can cause subtle neurological damage - upset stomach, headache, sleepiness, tingling/burning sensation
46
Folate (B9) functions
- 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
Folate (B9) sources
Fortified cereals, enriched grains, green leafy vegetables, orange juice, sunflower seeds, legumes
48
Folate (B9) deficiency
- anemia and diarrhea - megaloblastic anemia - birth defects: spinabifida - heart disease
49
Folate (B9) toxicity
- can mask B12 deficiency with folate supplements - hypersensitive people may suffer hives or resp problems
50
Cobalamin (B12) functions
- “cobalt containing compounds” - needed for normal folate function (DNA and red blood cell synthesis, metabolism of homocysteine) - maintains myelin sheath around nerves
51
Cobalamin (B12) functions
- only in animals foods (meats, liver, milk, eggs) - some fortified foods
52
Cobalamin (B12) absorption
Animal based diets —> (proteases) B12 —> Haptocorrin carrier (oesophagus) —> (proteases) —> intrinsic factor (small intestine) —> gut epithelial cells aka enterocyte —> blood stream —> liver
53
B12 deficiency
- can lead to pernicious anemia —> nerve damage - red blood cells can look enlarged (megaloblastic anemia)
54
B12 toxicity
No UL set
55
Pantothenic Acid (B5)
- component of coenzyme A
56
Pantothenic acid (B5) sources
- widespread in foods - reduced by freezing, canning, refining
57
Pantothenic acid (B5) deficiency and toxicity
Rare
58
Biotin (B7) functions
- coenzyme - AA metabolism (into glucose) - fatty acid synthesis - release of energy from fatty acids - DNA synthesis - rare deficiency/toxicity
59
Biotin (B7) sources
Cauliflower, liver, peanuts, cheese - protein avidin (raw egg whites) binds biotin and prevents absorption
60
Vit C functions
- antioxidant - collagen synthesis - enhances iron absorption from plant foods - makes other essential compounds (eg thyroid hormones, parts of DNA)
61
Vit C sources
Fruits: citrus, strawberries, kiwi Vegetables: broccoli, tomatoes, potatoes, cabbage, leafy greens, peppers
62
Vit C plateau
- 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
Vit C deficiency
Scurvy (pale skin, loss of teeth, sunken eyes)
64
Vit C toxicity
May cause GI distress in high doses
65
Bogus vitamins examples
Hesperidin, pangamic acid, rutin - marketed but unnecessary

PHAR300 (22 decks)

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