Water soluble vitamins lecture Flashcards
Biochemically, vitamins function as
Cofactors (co-enzymes) for enzymatic reactions
What are the carrier proteins for Adek
A- retinol binding protein
D- vitamin d binding protein
E-alpha tocopherol transfer protein
I-ApoE
Vitamin A is present in animals as … and plants as …
Preformed vitamin A
Provitamins A(beta carotene)
Active forms of vitamin A are
Retinol
Retinal(retinaldehyde)
Retinoic acid
B-carotene
Primary sources of vitamin A
Animal products: liver, egg yolk, dairy products (retinol)
Plant products: orange and red colored fruits and vegetables, green leafy vegetables(beta carotene)
Major functions of vitamin A
Differentiation
Growth
Reproduction
Vision
Also helps In functioning of zinc finger proteins
deficiency manifestations of vitamin A
Night blindness
Xerophthalmia(conjunctival and corneal xerosis)
Keratomalacia(when xerophthalmia persists for a long time)-softening of the cornea
Bitot’s spots(grayish white triangular plaques formed on conjunctiva)
Hyper keratosis
Normal serum levels of retinol binding protein
40 to 60 microgram/ml
Vitamin A levels in blood are a red flag when lower than…
25 milligram per deciliter
Sources of vitamin D
Sunlight, eggs, cheese, salmon, yoghurt
What are the forms of vitamin d
D2(ergocalciferol) derived from plants and other food sources
D3(cholecalciferol)synthesized by body when exposed to sunlight. Precursor is 7-dehydrocholestrol
Calcidiol(25(OH)D
Calcitriol(1,25(OH)2D most active
Main roles of vitamin D
Regulation of calcium and phosphorus levels
Promotes bone formation and mineralization
Normal 25 dihydroxyvitaminD levels in blood?
20 to 40 ng/mL
How to treat vitamin D deficiency?
Oral ergo calciferol at 50000 IU per week for 8 weeks
After, maintenance levels of cholecalciferol at 800 to 1000 IU per day from dietary and supplemental sources
Active form of vitamin E known as
Tocopherol
Main function of vitamin E
Very potent antioxidant
Quenches the lipid peroxidation chain and protects the plasma membrane from the attack of free radicals
Deficiency of vitamin E
No major disease states due to adequate levels in average diet
Sources of vitamin E
Trout Red bell pepper Avocado Sunflower oil Almonds
Vitamin E deficiency is seen in which persons?
People who
Cannot absorb dietary fat
Premature infants
Mutations in gene for tocopherol transfer protein
Deficiency causes neurological problems due to poor nerve conduction, and anaemia due to oxidative damage of RBCs
Detection of vitamin D deficiency
Alpha tocopherol test
Normal level usually with the range of 5.5-17 milligrams per liter
Treatment is giving high doses of vitamin E
Vitamin K some sources?
Broccoli Squash Parsley Tomatoes Swiss chard Kale Olive oil
2 types of vitamin K. They are
Phylloquinone(K1) and menaquinone(K2)
Main function of vitamin K(1)
Blood coagulation
Aids in gamma carboxylation of coagulation factors. Ie converting inactive prothrombin to thrombin(factor II)
Function of vitamin k2
Bone mineralization and prevents vascular calcification
Clinical manifestations of vitamin k deficiency
Bruising tendency
Mucous membrane hemorrhage
Post traumatic bleeding
Internal bleeding
Warfarin and dicoumarol act as anticoagulants how?
Competitive inhibition of gamma carboxylation system due to structural similarity with vitamin K
How is vitamin D deficiency discovered physically
Excessive bleeding occurring
What lab test is done to determine vitamin k deficiency
Prothrombin time test
Performed by adding calcium and thromboblastin(an activator of the extrinsic pathway) to the blood sample and measuring the time required for fibrin blood clot formation
Average blood clot time range?
10 to 13 seconds
Treatment for vitamin K synthesis is by which drug
Phytonadione (k1)
Catalyzes hepatic synthesis of blood clotting factors. Factor II(active prothrombin) factor VII factor IX factor X
