Vitamins Flashcards
(83 cards)
1
Q
Biotin AI
A
30 mcg
2
Q
Vitamin K AI
A
120 mcg / 90 mcg
3
Q
Vitamin B6 RDA
A
1.3-1.7 mg
4
Q
Folate RDA
A
400 mcg
5
Q
Vitamin C RDA
A
90 mg / 75 mg
6
Q
Pantothenic Acid AI
A
5 mg
7
Q
Riboflavin RDA
A
1.3 mg / 1.1 mg
8
Q
Vitamin A RDA
A
900 mcg RAE / 700 mcg RAE
9
Q
Vitamin D RDA
A
15 mcg
10
Q
Vitamin B12 RDA
A
2.4 mcg
11
Q
Thiamin RDA
A
1.2 mg / 1.1 mg
12
Q
Niacin RDA
A
16 mg / 14 mg
13
Q
Vitamin E RDA
A
15 mg
14
Q
Differences between macro and micronutrients
A
- Energy vs. no energy
- Quantity amount (grams vs micro or milligrams)
- All vitamins are essential (only essential macronutrients are glucose, linoleic/linolenic acid, and 9 AAs)
15
Q
Fat-soluble vitamin absorption/transport/storage/excretion
A
Absorbed in the small intestine into the lymphatic system, which requires bile, digestive enzymes and micelles. Transported via chylomicrons to the liver. Excess stored mainly in the liver and fat tissue (except K). Small amounts excreted in bile.
16
Q
Water-soluble vitamin absorption/transport/storage/excretion
A
Absorbed in the small intestine directly into the blood stream via the portal vein. Transported in the blood, often bound to proteins such as albumin. Very minimal storage. Excreted in the urine (except B12 and B6)
17
Q
Vitamin A functions
A
- Vision: retinal turns visual light into nerve signals, retinoid acid helps maintain normal differentiation of cells in eye (cornea, rod cells)
- Growth & development: retinoid acid required for cell formation
- Reproduction: requires retinol or retinal
- Immunity: retinoids help maintain epithelial layers, differentiation of some cells produced by immune system
18
Q
Vitamin A deficiency
A
- Xerophthalmia (irreversible blindness)
- Follicular hyperkeratosis
- Impaired immunity
- Poor growth
19
Q
Vitamin A toxicity
A
Hypervitaminosis A (acute, chronic, teratogenic); hypercarotenemia
20
Q
Rhodopsin
A
A molecule in rod cells: opsin (protein) + cis-retinal
21
Q
Visual cycle
A
When rhodopsin is exposed to bright light, cis-retinal becomes trans-retinal. Opsin is released from retinal, which sends nerve impulse that carries visual information to the brain. Retinal is reused (some lost), and rhodopsin is reformed.
22
Q
Xerophthalmia
A
Irreversible blindness caused by vitamin A deficiency. Disease progression:
- Night blindness
- Decreased mucus production
- Development of Bitot’s spots, conjunctival xerosis
- Cornea softens
- Scarring
23
Q
Follicular hyperkeratosis
A
Vitamin A deficiency. Normal epithelial cells in the underlying skin layers are replaced with keratinized cells. Hair follicles become plugged with keratin, which causes bumpy, rough, and dry skin.
24
Q
Acute vitamin A toxicity
A
Caused by ingestion of 100x RDA within a short period. Symptoms include GI upset, headache, blurred vision, muscular uncoordination
25
Chronic vitamin A toxicity
Caused by a large intake of vitamin A over a long time. Symptoms include bone/muscle pain, hip fractures, skin disorders, headache, dry skin, hair loss, increased liver size, double vision
26
Teratogenic vitamin A toxicity
Causes spontaneous abortion or birth defects
27
Vitamin D nomenclature
D3: cholecalciferol, found in animal products
D2: ergocalciferol, found in plants, fortified foods
28
How active vitamin D is formed in the body
1. Sunlight converts 7-dehydrocholesterol to previtamin D3, and forms D3 with body heat
2. Liver hydroxylates D3 to 25-OH-D3
3. Kidney hydroxylates more to 1,25-(OH)2 D3, which is the active form / hormonal form (aka Calcitriol)
29
Vitamin D functions
1. Regulates blood Ca and P levels. Calcitriol increases intestinal absorption of Ca from foods. With PTH, releases calcium from bone into blood, which increases blood Ca levels. Prevents Ca from being excreted in urine.
2. Bone growth and development
3. Cell differentiation
30
Vitamin D deficiency
Rickets (kids), osteomalacia (adults)
31
Rickets
Caused by vitamin D deficiency in kids. Symptoms include bowed legs, outward bowed chest, knobs on ribs, rapid enlargement of head, muscle spasms
32
Osteomalacia
Caused by vitamin D deficiency in adults. Symptoms include loss of Ca, soft, flexible, brittle, deformed bones. Bending of spine, bowed legs.
33
Vitamin D toxicity
Hypercalcemia: over absorption of Ca, which causes irreversible calcification of heart, lungs, and kidneys. Narrows pulmonary arteries, facial changes, mental retardation. Infants most susceptible.
34
Vitamin K nomenclature
K1: phylloquinones (plants)
K2: menaquinones (animal tissue, intestinal bacteria)
35
Vitamin K functions
Synthesis of blood clotting factors and bone proteins
36
Vitamin K deficiency
Hemorrhage, bone/hip fractures
37
Vitamin K toxicity
Not common. High doses can reduce effectiveness of anticoagulant drugs.
38
Vitamin E nomenclature
4 tocopherols and 4 tocotrienols. Most active form is alpha-tocopherol
39
Vitamin E functions
Antioxidant. Protects PUFAs within cell membrane. Prevents cell lysis/cell death. Prevents the alteration of cell's DNA and risk for cancer development. Limits LDL oxidation, a contributor to atherosclerosis.
40
Vitamin E deficiency
Hemolytic anemia, peripheral neuropathy
41
Hemolytic anemia
Hemolysis, ruptured RBCs
42
Vitamin E toxicity
Hemorrhagic effect in adults. Inhibits vitamin K metabolism and anticoagulants
43
Antioxidants
Compounds that stop the propagation of free radical chain reactions. Free radicals steal electrons from stable compounds, making them unstable. Antioxidants prevent the breakdown of substances in food or the body, particularly lipids, by donating electrons to oxidizing agents. Antioxidants in the body include vitamins C, E, and beta-carotene.
44
Major food sources for fat-soluble vitamins
```
Preformed vitamin A: fish liver oil
Beta-carotene: squash
Vitamin D: salmon (or sunlight)
Vitamin E: almonds
Vitamin K: kale (also intestinal bacteria)
```
45
Major food sources for water-soluble vitamins
```
Thiamin: pork
Riboflavin: milk
Niacin: poultry
B6: bananas
Folate: orange juice
B12: liver
Pantothenic acid: whole grains
Biotin: egg yolks
Vitamin C: orange
```
46
Thiamin coenzyme
thiamin pyrophosphate (TPP)
47
Riboflavin coenzymes
```
Flavin adrenine dinucleotide (FAD)
Flavin mononucleotidue (FMN)
```
48
Niacin coenzymes
NAD, NADH, NADP, NADPH
49
Vitamin B6 coenzyme
Pyridoxal phosphate (PLP)
50
Folate coenzyme
tetrahydrofolate (THF)
51
Vitamin B12 coenzymes
Methylcobalamin
| 5-deoxyadenosylcobalamin
52
Pantothenic acid coenzyme
part of CoA
53
Thiamin functions
Coenzyme in energy metabolism (decarboxylation reaction to convert pyruvate to acetyl-CoA)
Pentose synthesis
Nerve conduction
54
Thiamin deficiency
Beriberi, Wernicke-Korsakoff Syndrome
55
Beriberi
Caused by deficiency of thiamin. Symptoms include anorexia, weight loss, weakness, peripheral neuropathy, poor memory, confusion.
56
Wernicke-Korsakoff Syndrome
Caused by deficiency of thiamin among alcoholics. Alcohol decreases thiamin absorption, alcohol increases thiamin excretion in urine, and alcoholics may consume a poor-quality diet. Symptoms include changes in vision, ataxia (inability to coordinate muscles), and impaired mental functions
57
Thiamin toxicity
None
58
Riboflavin functions
Coenzyme in numerous oxidation-reduction reactions, including energy metabolism
59
Riboflavin deficiency
Ariboflavinosis
1. Glossitis: inflammation of tongue
2. Cheilosis: cracks at corner of mouth
60
Riboflavin toxicity
None
61
Niacin functions
Coenzyme in numerous oxidation-reduction reactions, including energy metabolism. Synthesis and breakdown of fatty acids
62
Niacin deficiency
Pellagra (symptoms include diarrhea, dermatitis, dementia, and if untreated, death). Associated with a corn-based diet, used to be a major public health problem in the US.
63
Niacin toxicity
No toxicity from food. From nicotinic acid supplementation, can get:
1. Niacin flush: flushing of the skin
2. GI upset
3. Liver damage
64
Vitamin B6 functions
```
Coenzyme in amino acid metabolism
Neurotransmitter synthesis
Heme synthesis
Homocysteine metabolism
Lipid metabolism
```
65
Vitamin B6 deficiencies
```
Microcytic hypochromic anemia
Confusion
Convulsions
Dermatitis
Depression
```
66
Microcytic hypochromic anemia
Caused by B6 deficiency. Small, pale red blood cells that lack sufficient hemoglobin and thus have reduced oxygen-carrying abilities. Also caused by iron deficiency.
67
Vitamin B6 toxicity
None from food. Excess from supplements can cause neuropathy and skin lesions
68
Vitamin B12 functions
Coenzyme in DNA synthesis, cell division, folate metabolism, nerve function, homocysteine metabolism
69
Vitamin B12 deficiencies
```
Pernicious anemia (looks like megaloblastic anemia)
Nerve degeneration
Elevated homocysteine (therefore risk of heart disease)
```
70
Pernicious anemia
Caused by B12 deficiency. Associated with nerve degeneration, which can result in eventual paralysis and death
71
Vitamin B12 toxicity
None
72
Folate functions
Coenzyme in DNA synthesis, amino acid metabolism, homocysteine metabolism
73
Folate deficiencies
```
Megaloblastic anemia
Neural tube defects
Elevated homocysteine (therefore risk of heart disease)
```
74
Megaloblastic anemia
Aka macrocytic anemia. Caused by folate deficiency. Characterized by large, immature RBCs that result from the inability of precursor cells to divide normally.
75
Folate toxicity
None
76
Digestion and absorption of vitamin B12
In animal-based foods, vitamin B12 is bound to protein. In the stomach, HCl denatures the protein and B12 is released. B12 then binds to R-protein (which is produced in the saliva). In the small intestine, proteases cleave B12 from the R-protein. B12 binds to intrinsic factor (which is produced in the stomach). The B12-IF complex is absorbed by intestinal cells into the bloodstream.
77
Vitamin C functions
```
Antioxidant
Synthesis of collagen, hormones and neurotransmitters
Enhances immune function
Detoxification of drugs/carcinogens
Reactivates vitamin E
```
78
Vitamin C deficiency
Scurvy
79
Scurvy
Develops when deficient in vitamin C for 20-40 days. Symptoms include fatigue, pinpoint hemorrhages (aka petichiae), bleeding gums, poor wound healing, joint pain, fractures
80
Vitamin C toxicity
GI distress (nausea, abdominal cramps, diarrhea), increased risk of iron overload
81
Vitamins involved in bone health
Vitamin A: retinoid acid required for cell formation, thus helps with growth and development
Vitamin D: maintains body's concentrations of calcium
Vitamin K: synthesizes bone proteins
Vitamin C: synthesizes collagen, which is a fibrous protein found in bone, among other connective tissue
82
Processed grains are enriched with...
```
Thiamin
Riboflavin
Niacin
Folate
Iron
```
83
Essential nutrient requirements
1. Has a specific biological function
2. Removing it from the diet leads to a decline in biological function
3. Adding it back returns function to normal
