Ch.12 Fat-Soluble Vitamins Flashcards
Which vitamins are water soluble?
B complex and C
Which vitamins are fat soluble
A,D,E,and K
Where are fat soluble vitamins absorbed?
The small intestine, along with dietary fat, and carried by chylomicrons into the lymph circulation
What aids in fat soluble vitamin absorption?
Bile produced in the liver and stored in gallbladder.
Which is the only vitamin made in body?
Vitamin k is made by bacteria in the ileum of the small intestine and in the large intestine. (Small amounts)
Forms of vitamin A
Retinoids, carotenoids
What is the active form of vitamin A?
Preformed vitamin A(retinoids)
What are the dietary sources of retinoids?
Liver, fish oils, fortified dairy products and eggs.
What are the “provitamins of vitamin A?
Carotenoids (can be converted to vitamin A)
What are the different names of carotenoids?
Alpha and beta-carotene and beta cryptoxanthin
Dietary sources of carotenoids?
Dark green and yellow orange vegetables and fruits
Which conversion is irreversible ?
Retinal -> retinoic acid. (Retinyl esters -> retinol ->retinal Reversible)
RDA for men and women Vitamin A
Men 900 micrograms RAE
Women 700 micrograms RAE
Intake meets DRI
Transport after liver (vit. A)
Retinoids are bound to retinol binding protein
Carotenoids are carried by VLDL
90% stored in liver for months
Function of Retinoids
- Growth and development (retinoic acid imp. To epithelial cells)
- cell differentiation(stem cells into specialized cells)
- vision (retinal-pool depleted = night blindness. Rhodopsin)
- immune function (maintenance of epithelium)
Carotenoids functions
Decrease risk of some diseases, antioxidant functions
-cancers
-CV disease
-eye disease (macular degeneration and cataracts
Do not supplement
Deficiencies in vitamin A
- night blindness
- Xerophthalmia (irreversible blindness)
- follicular hyperkeratosis
Toxicities of vitamin A
Hypervitaminosis A
UL: 3000 micrograms/ d retinol
Acute,chronic and teratogenic toxicity
Where can you find vitamin D2
Fatty fish, cod liver oil, fortified dairy products and fortified breakfast cereals .
Where do you find vitamin D3 (active and inactive)
Sunlight changes 7-dehydrocholesterol to cholecalciferol
Travels to liver 25-OH vitamin D3 (inactive form) and then into kidneys, where converted to bioactive form.
*requirement: sunlight 2-3 x /week 10-15 min
RDA and DV for vitamin D
Under age 70: 600 IU
Over 70: 800 IU
Breastfed infants: 400 IU/d
DV: 10 micrograms (400 IU)
How is vitamin D absorbed?
-Via micelles and transported via chylomicrons in lymph system.
-bound to protein in the blood when enters body through food or skin
-
Where is vitamin D stored?
Adipose tissue.
Functions of vitamin D
- Calcium and Phosphorus Homeostasis (aids in increasing absorption of Ca and P. Aids in release of Ca and P from bone; if blood levels are low
- Bone health
- immune function
- chronic diseases
What is the active form of vitamin D?
Calcitrol
Deficiencies of vitamin D
Children: rickets
Adults: osteomalacia
Toxicities of Vitamin D
Occur with supplementation cause hypercalcemia
UL: 4000 UI (Valium deposits in soft tissue)
How many compounds are there in vitamin E and what were they
4 tocopherols: alpha most active; gamma for potentially beneficial
4 tocotrienols
Dietary sources of vitamin E
Plant oils (canola), wheat germ, avocado, almonds, peanuts and sunflower seeds
RDA and DV of vitamin E
15 mg of alpha-tocopherol (based on hemolysis prevention)
Adults consume 2-3 RDA
DV: 30 IU (20 mg)
Vitamin E absorption and transport
- depends on fat intake
- passively via micelles into chylomicrons
- chylomicron remnants transport to liver
- repackaged and transported via lipoprotein (no specific transport protein)
Where is vitamin E stored?
Adipose tissue
Vitamin E excretion
Bile, urine and skin
Vitamin D excretion
Bile urine, and small amount in urine.
Vitamin A excretion
Small amounts in urine
-carotenoids via bile
Absorption of vitamin A
Packaged with chylomicrons and transported via the lymph system
Which vitamin acts as an antioxidant?
Vitamin E. Stops lipid peroxidation caused by free radicals-peroxyl radical.
Works with vitamin C
What are other antioxidant compounds from vitamin E?
Glutathione peroxidase -eliminates hydrogen and lipid peroxides . -selenium Superoxide dismutase -eliminate super oxide radicals -copper, Zinc and Mg
Deficiency vitamin E
Hemolytic anemia-rare in humans
Pre-term infants and smokers are most susceptible
Immune function impairment and neurological changes
Toxicity vitamin E
Interfere with vitamin K and cause hemorrhaging
UL 1000 mg alpha tocopherol from natural sources (1100 IU from synthetic )
Forms of vitamin K
Menaquinones: synthesized by bacteria in colon (10%) (from fish oils and meats)
Phylloquinones: most biologically active (from plants: green leafy vegetables, broccoli, peas, and green beans
AI women and men vitamin K. DV
Men: 120 micrograms daily
Women: 90 “”
DV: 80 micrograms
Absorption and transportation of vitamin k
- Absorbed in small intestine-passive diffusion, via chylomicrons in lymph
- Transported via lipoproteins, VLDL for storage or HDL and LDL for transport to cells
Where is vitamin K stored?
Liver
Excretion of Vitamin K
Primarily bile; sm amount urine
Function of vitamin K
Synthesis of blood clotting factors, preprothrombin to protrhombin
-bone metabolism
Deficiency vitamin K
Rare.
Newborns; long term antibiotic use; fat malabsorption
Toxicity vitamin K
No UL
