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52 Cards in this Set
- Front
- Back
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Vitamin needs
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We need about 1 oz (28g) for every 70 kg of food we consume
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Vitamin
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Essential organic substances needed in small amounts in the diet for the normal fxn, growth, and maintenance of body tiss
Can't be synthesized in suff amts to meet needs or at all Must be organic, must have a biochemical fxn in the body and must be required in diet in very small amts |
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Vitamins
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Both plant and animal sources
Synthetic and natural vit have same chem structure and work equally, but potency is different |
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Lipid-soluble vitamins
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A, D, E, K
Are excreted less readily from body, less susceptible to cooking loss and more potentially toxic |
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Vit A and D
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Can cause toxicity with long term intake of 3x human needs
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Vit E, C, B-6, and B-12 and niacin
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Can cause toxicity when consumed in very large amts (15-100 times human needs)
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Lipid-soluble
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Except for K, are not readily excreted from body, but water-soluble are
Two exception are vit B-6 and B-12, which are stored much longer than both the other water-sol vitamins and vit K |
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Water-soluble
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An occasional lapse generally causes no harm (no niacin for 10 days or no vit C for 20-40 days before symptoms of deficiency)
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Fat mal-absorption
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(Cystic fibrosis, celiac disease, Crohn's disease) is associated with mal-absorption of the lipid-soluble, and alcohol and some intestinal diseases can lower the absorption of some water-soluble vit
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Absorption of vitamins
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Fat-soluble - absorbed along with dietary fat - 40-90% of these are absorbed when consumed in recommended amts - some diseases lower absorption
Water-soluble - 90-100% are absorbed from diets with recommended amts - excess alcohol and intestinal diseases decrease absorption |
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Transport of vitamins
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Dietary lipid-soluble - transported by chylomicrons and reach liver via chylomicron remnants and stored or redistributed - exception is retinoate, that can bind to serum albumin and be transported to liver via portal vein
Water-soluble - transported via portal vein to liver and stored or redistributed |
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Functions of Vit A
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Hormone
Retinal - visual pigment Retinol - immune system Retinoate - cell growth and proliferation |
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Functions of Vit D
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Hormone
Blood Ca regulation |
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Functions of Vit E
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General antioxidant
Coenzyme fxn |
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Functions of Vit K
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Prosthetic group coenzyme
Carboxylation of blood and bone proteins - of glutamate R group |
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Vit A
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Deficiency is m/c cause of non-accidental blindness in world
Over 90% stored in liver and small amounts in adipose tiss, kidneys, bone marrow, testicles, and eyes |
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Preformed Vit A
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As retinol (retinoid) and retinyl esters (no vit A activity - storage)
Found in animal products Absorption of retinol can be as high as 90% After absorption is transported as retinyl esters |
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Provitamin A
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Caroteniods
Some can be converted to retinoid form Intestinal cells can split B-carotene in two molecules of retinoids Found in plant products Absorption is much lower than that of retinol |
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Carotenoids and retinoids
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Inter-conversions of B-carotene and various retinoids
The synthesis of retinoate is a "dead end" in metabolic terms |
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Carotenoids to Retinoids
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Enzymatic conversion of carotenoids occurs in liver or intestinal cells, forming retinal and retinoic acid
Provitamin A carotenoids - beta-barotene, alpha-carotene, beta-cryptoxanthin Other carotenoids - lutein, lycopene, zeaxanthin |
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Transport of vitamins
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Dietary lipid-soluble - transported by chylomicrons and reach liver via chylomicron remnants and stored or redistributed - exception is retinoate, that can bind to serum albumin and be transported to liver via portal vein
Water-soluble - transported via portal vein to liver and stored or redistributed |
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Functions of Vit A
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Hormone
Retinal - visual pigment Retinol - immune system Retinoate - cell growth and proliferation |
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Functions of Vit D
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Hormone
Blood Ca regulation |
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Functions of Vit E
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General antioxidant
Coenzyme fxn |
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Functions of Vit K
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Prosthetic group coenzyme
Carboxylation of blood and bone proteins - of glutamate R group |
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Vit A
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Deficiency is m/c cause of non-accidental blindness in world
Over 90% stored in liver and small amounts in adipose tiss, kidneys, bone marrow, testicles, and eyes |
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Preformed Vit A
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As retinol (retinoid) and retinyl esters (no vit A activity - storage)
Found in animal products Absorption of retinol can be as high as 90% After absorption is transported as retinyl esters |
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Provitamin A
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Caroteniods
Some can be converted to retinoid form Intestinal cells can split B-carotene in two molecules of retinoids Found in plant products Absorption is much lower than that of retinol |
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Carotenoids and retinoids
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Inter-conversions of B-carotene and various retinoids
The synthesis of retinoate is a "dead end" in metabolic terms |
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Carotenoids to Retinoids
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Enzymatic conversion of carotenoids occurs in liver or intestinal cells, forming retinal and retinoic acid
Provitamin A carotenoids - beta-barotene, alpha-carotene, beta-cryptoxanthin Other carotenoids - lutein, lycopene, zeaxanthin |
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Vit A in foods
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Women - 700ug
Men - 900ug Daily value - 1000ug Beef liver, sweet potato, carrots, kale, broccoli Particularly in dark-green, orange, red and yellow veggies |
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Conversion values for retinol activity equivalents
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1 retinol activity equivalent (RAE) - 1ug retinol, 12ug beta, 24ug alpha and beta-crypt
1 IU vit A activity - .3ug retinol, 3.6ug beta, 7.2ug alpha and beta-crypt |
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Fxns of vit A
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Vitamin A: hormone - retinal (visual pigment), retinol (immune system), retinoate (cell growth and proliferation)
Vitamin A analogs in dermatology: retin-A and Accutane to treat acne and psoriasis, meds to lessen the damage from excess sun and UV light exposure |
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Carotenoid fxns
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Prevention of CVD - antioxidant capabilities, >5 servings of fruits and veggies
Cancer prevention - antioxidant capabilities, lung,oral,prostate cancers, foods more protective than supplements Age-related macular degeneration Cataracts |
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Deficiency
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Night blindness
Keratinization of epithelial tiss Xerophthalmia Blindness |
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Toxicity
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Acute - GI upsets/nausea, HA, muscle uncoordination
Chronic - Liver damage, hair loss, bone/muscle pain, dry skin and mucous membranes, hemorrhages, coma, fractures Teratogenic - fatal malformation, spontaneous abortion |
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Vit D
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1933 - milk first fortified with vit D
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Vit D in foods
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Women AI - 5ug
Men AI - 5ug Daily value - 10ug Cod liver oil, salmon, herring, tuna, eel |
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Vit D synthesis
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Prohormone
From cho and sun exposure Insufficient sun exposure makes this a vit Activated by enzymes in liver ande kidneys Deficiency diseases - rickets, osteomalacia Further from equator, UV decreases Decreases by 70% by age 70 Too much melanin in dark-skinned people may block UV light and synthesis Sunscreens with SPF >8 may prevent synthesis UV light produces 80-100% of vit D we use Few foods provide |
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Active vit D
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Synthesized in skin or from diet, is a hormone: 1,25(OH)2VitaminD3 (calcitriol)
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Fxns of vit D
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Calcitriol and PTH interact to control blood pressure (Ca)
Low blood Ca triggers - PTH and calcitriol mobilize Ca from bone, PTH also reduces Ca excretion by kidneys and stim kidney secretion of calcitriol, calcitriol stim intestinal Ca absorption When blood Ca is too high, calcitonin responds by promoting Ca deposition in the bone (off switch) |
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Vit D deficiency
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Rickets - poor bone mineralization in children
Osteomalacia - soft bones in adults |
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Toxicity of vit D
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UL - 50ug/d (2000 IU/day)
Regular intake of 5-10x the AI can be toxic Over-absorption of Ca increases Ca excretion Ca deposits in kidneys, heart and blood vessels, narrowing of pulmonary arteries and aorta, facial changes, mental retardation Results from consuming megadoses not excess sun exposure |
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Vit E
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Tocopherols (more active compounds)
Tocotrienols Plant oils are rich sources |
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Food sources of vit E
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Women RDA - 15mg
Men RDA - 15mg Daily value - 30 IU Sunflower oil, safflower oil, mayonnaise, sunflower seeds, almonds, canola oil, avocado |
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Fxns of vit E
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General antioxidant
Important for protection the membrane of nerve and RBC (deficiency may cause neural damage and hemolytic anemia) One of several compounds helpful in reducing oxidative stress |
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More better?
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Body does not rely solely on vit E for antioxidant protection
Better protection appears to be provided by combo |
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Toxicity of vit E
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Relatively non-toxic, but excessive amts can interfere with vit K in blood clotting (risk of hemorrhaging, particularly for people taking anticoagulants)
UL is 1000mg of a-tocopherol from natural sources 1500 IU - natural sources 1100 IU - synthetic sources |
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Vit K
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PHylloquinones (K1) from plant sources - main dietary form and more biologically active
Menaquinones (K2) from fish oils, meats, and intestinal bacteria |
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Vitamin K
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Essential for normal blood clotting and important for bone health
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Vit K in foods
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Women AI - 90ug
Men AI - 120ug Daily value - 89ug Kale, spinach, turnip greens, brussel sprouts, broccoli |
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Blood coagulation
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forming a blood clot requires the participation of vitamin K
Specifically provides Ca-binding capacity in blood prot by carboxylation of glutamate residues |
