Vitamins And Minerals Flashcards
1
Q
Water soluble (Non-B)
A
Absorbic Acid
2
Q
Water soluble (B-Complex)
A
-Energy releasing B1- thiamine B2- riboflavin B3-niacin Biotin Pantothenic acid -Hematopoietic: Folic acid, B12 -Others - B6-pyridoxine, Pyridoxal, pyridoxamine
3
Q
Fat soluble
A
Vit A - retinol
Vit D - cholecalciferol
Vit E - tocopherols
Via K - phylloquinones, menaquinones
4
Q
Retinoids
A
-family of compounds related to retinol, vision, growth, reproduction, maintenance of epithelial tissues.
5
Q
Retinol
A
Found in animal issues
6
Q
Retinal
A
-oxidation of retinol, can be interconverted
7
Q
Retinoic Acid
A
-mediates most of actions of retinoids except vision
8
Q
B-carotene
A
- forms two molecules of retinal
9
Q
Absorption and Transport
A
- retinol esters in diet, hydrolyzed in intestine—-> retinol + FFA
- Reesterified to long chain FA in mucosa and secreted with the chylomicrons
- retinol stored in liver
- transported by plasma retinol binding protein
- receptor mediated uptake in cells - RAR
- activates gene transcription
10
Q
Mechanism of action of Vit A
A
- Retinoic acid binds to receptor proteins in nucleus of target tissues
- Stimulates retinoids specific RNA synthesis
- RA-receptor protein part of the superfamily of transcription regulators that include (steroid and thyroid hormones, 1,25-dihydroxycholecalciferol)
11
Q
Functions of Vit A
A
- Vision - component of visual pigment (rhodopsin) 11-cis retinal bound to opsin
- Rhodopsin - all trans retinal + opsin + nerve impulse
- Regeneration
- Isomeric action of all trans retinal to 11-ICS retinal
- Spontaneous combination with opsin—-> rhodopsin
- Growth - deprivation results in loss of appetite, slow bone growth, CNS damage
- Reproduction - retinol and retinal support spermatogenesis and prevent fetal resorption. RA inactive in reproduction and vision but promotes growth and differentiation of epithelial tissue.
- Maintenance of epithelial cells - essential for normal differentiation of epithelial cells
12
Q
Sources of Vit A
A
- Liver, kidney, cream, butter and egg yolk -preformed Vit A
- Dark green and yellow fruit and veggies are sources of Beta-carotene
- Deficiency - night blindness, xerophthalmia (dryness of conjunctiva and cornea, cornea ulceration follows, which can lead to blindness)
13
Q
Vit A clinical indications
A
Acne and psoriasis - topical application of all trans retinoic acid (tretinoin) for mild: 13-cis retinoic acid (isotretinoin) orally for severe cases
-prevention of chronic disease- populations with high beta-carotene have decreased heart disease, lung and skin cancer, cataracts and macular degeneration
14
Q
Toxicity of retinoids
A
- Hypervitaminosis A - exceeding 7.5 mg/day, dry skin, enlarged, cirrhosis liver, rise in intracranial pressure, excess in pregnancy could cause congenital malformation in fetus
- Isotretinoin - teratogenic and absolutely contraindicated in women of childbearing potential potential unless severe acne is unresponsive. Prolonged treatment can lead to hyperlipidemia and increased LDL/HDL, increased risk for CVD
15
Q
Vit D
A
- group of sterols with hormone like functions
- Ergocalciferol and cholecalciferol - preformed D activity
- may be synthesized by light from 7-dehydrocholesterol in skin
16
Q
Function of 1,25-diOH D3
A
- maintain adequate levels of Ca by:
1. Increasing uptake of Ca by intestine
2. Decreasing Ca loss by kidney
3. Stimulating resorption of bone if necessary to maintain serum Ca
17
Q
Vit D3
A
-fatty fish, liver, egg yolk
18
Q
Vit D clinical indications
A
Deficiency - rickets in children cause by incomplete mineralization of bone
- Osteomalacia in adults caused by demineralization of pre existing bones
- RDA - 200IU/day, 800IU/day can reduce osteoporotic fractures
- Renal rickets - from chronic renal failure, inability to form active 1,25-diOH D3
- Hypoparathyroidism - causes hypocalcemia and hyperphosphatemia
19
Q
Vit D toxicity
A
Most toxic of all vitamins
-fat soluble so it can be stored in your body
Lack of Vit D causes loss of appetite, nausea, thirst, bone resorption and deposition of calcium in organs
20
Q
Vit E
A
- family of tocopherols, alpha-tocopherols is most active
Primary function - antioxidant in cell lipid components
2) Sources: vegetable oils, liver, eggs
RDA - 10mg/day for men, 8 for women
3) deficiency
-restricted to premature infants
-supplemental not recommended for any prevention of chronic disease
21
Q
Vit K
A
- blood clotting
- Prothrombin factors 2,7,9 and 10
- not enough K and no carboxylation reaction, not allowing clotting
1) sources of Vit K : cabbage, cauliflower, spinach, egg yolk and liver, also synthesized by gut bacteria - no RDA
2) toxicity - prolonged administration can produce hemolytic anemia and jaundice in infants
22
Q
B-vitamins
A
- water soluble, have important functions as coenzymes or constituents of coenzymes essential in metabolism
- whole grains and cereals are good sources
23
Q
Thiamine (B1)
A
- thiamine pyrophosphate is active form
- acts as a coenzyme in formation or degradation of alpha-ketols and oxidative decarboxylation of alpha-keto acids
- oxidative decarboxylation of pyruvate and alpha-ketoglutarate is important in energy metabolism especially the nervous system
- Wernicke-Korsakoff syndrome - dietary insufficiency or malabsorption
24
Q
Riboflavin (B2)
A
- water soluble and light sensitive
- function as flavin coenzymes (FAD, FADH)
- Flavins are important for: energy production, metabolism of drugs and toxins, antioxidant, protects against cataract formation, maintains the integrity of mucous membranes, activates B6, promotes nail, skin and hair health
- Deficiency may lead to anemia by impairing Fe absorption, also ariboflavinosis
25
Niacin (B3)
-name from nicotinic acid and nicotinamide
- NAD and NADP serve as coenzymes in redox reactions
- NAD functions in degradation of carbohydrates, fats, proteins and alcohol
-NADP functions in synthesis of fatty acids and cholesterol
Niacin deficiency - pellagra; rash on skin normally exposed to sunlight, and on both sides of the body
26
Pyridoxine- Vit B6
- biologically active as Pyridoxal phosphate
- functions as a coenzyme in reactions catalyzing AA's
Transamination: oxaloacetate +glutaminate -----> aspartate + alpha-ketoglutarate
Deamination: serine -----> pyruvate + NH3
Decarboxylation: histidine -----> histamine + CO2
Condensation: Gly + succinyl CoA----> gamma-aminolevulinic acid
Deficiencies occur with: alcoholics, oral contraceptives, newborns with low B6 formulas, isoniazid treatment of tuberculosis
27
Folic Acid- Vit B9
- essential in one-carbon metabolism for synthesis of number of compounds.
- most common deficiency in US
Tetrahydrofolate - receives one-carbon fragments from donors ( Ser, Gly, His) transfers them to intermediate sin synthesis of amino acids, purines and thimidine
28
Causes of folic acid deficiency
- pregnancy, poor absorption, alcoholism
- treat deficiency with dihydrofolate reductase inhibitors
- folate and neural tube defects result
- folic acid supplementation eliminates the neural defects and anencephaly
29
Vit B12
- cobalamin contains a corrin ring system, cobalt is held in the center of the rings. Commercial preparation is cyanocobalamin
- converts homocysteine to methionine
- converts methylmalonyl CoA to Succinyl CoA
- synthesized only by microorganisms, not plants
- animals obtain B12 preformed in foods derived from other animals
- intrinsic factor, a glycoproteins synthesized by the gastric parietal cells is essential for B12 absorption
- Significant amounts of B12 are stored in the body
30
Deficiency of B12
- pernicious anemia
- CNS symptoms: numbness and tingling, difficulty maintaining balance, depression, confusion, dementia, poor memory, mouth soreness
31
Absorbing Acid - Vit C
- essential coenzyme in hydroxyl action reactions, especially collagen production
- required for wound healing, normal connective tissue maintenance
- facilitates Fe absorption in the small intestine
- water soluble antioxidant
- deficiency results in scurvy characterized by gingival hemorrhage, corkscrew hair with petechiae, periungual hemorrhage, bruising and swollen joints
32
Biotin
- metabolism of carbohydrates, fat, and proteins
- cooperates with blaming B2, B3, and B6
- manufacture of glycogen, fat and detoxification
- source: food, made by the bacteria in the intestines
- essential in cell growth
- chronic eating of raw egg whites limits biotin absorption.
33
Pantothenic acid
- Component of CoA and acyl carrier protein
- CoA contains a thiol group to carry the acyl group as an activated thiol ester
- Sources: eggs, liver, yeast but widely distributed
- No RDA
34
Iron
- essential for hemoglobin and myoglobin production as well as co-factor for many reactions
- deficiency leads to anemia, characterized by pale mucous membranes in the eye and tongue
35
Calcium
- essential for bone mineralization, activator of glycogen degradation, isocitrate dehydrogenase, and pyruvate dehydrogenase phosphatase, insulin release, muscle action, nitric oxide synthase, cell signaling, clotting
36
Iodine
- essential in small amounts to make thyroid hormones
- Iodine deficiency disorders: goiter, cretinism, reduced mental and physical development, increased perinatal and neonatal mortality
