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58 Cards in this Set
- Front
- Back
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Bioavailability
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*The availability of vitamins from foods
*Depends on: *Quantity provided by the food *Amount absorbed & used by the body *Other factors: *Efficiency of digestion *Person’s previous nutrient intake & nutrition status *Other foods eaten at the same time *Method of food preparation *Source of the nutrient (naturally occurring, synthetic, or fortified) |
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Precursor
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*Inactive form of a vitamin
*Also called a provitamin *Must be converted to the active form |
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Solubility
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*Determines how a vitamin is absorbed, transported, stored, & excreted
*Types: 1. Fat-soluble 2. Water-soluble |
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Fat Soluble Vitamins
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*A, D, E, & K
*Occur in fats & oils *Absorbed the same as lipids *Stored in liver & fatty tissues *Not readily excreted & can become toxic |
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Vitamin A
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1. Retinoic Acid
2. Retinol 3. Retinal *Vitamin A has a role in immunity *90% stored in liver |
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Retinoic Acid
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*Acts as a hormone
*Has a role in gene expression *Regulates cell differentiation *Maintains integrity of epithelial cells |
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Retinol
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*Supports reproduction
*Major transport & storage form |
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Retinal
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*Active in vision
*Maintains clear cornea *Participates in light detection |
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Beta-Carotene
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*Is a plant-derived precursor
*Is an extremely effective antioxidant |
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Antioxidants
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*Protect other compounds from attack from oxygen
*Free radicals can form from oxidation |
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Oxidation Damage and Diseases
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*Age-related blindness
*Alzheimer’s *Arthritis *Cataracts *Diabetes *Kidney disease |
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Vitamin A Deficiency
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*Affects cell differentiation & maturation
*Hardening of cornea *Rough, scaly, hard skin *Drying & hardening of salivary glands *Lumps of keratin around hair follicles *Decreased immunity |
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Vitamin A Toxicity
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*Poses a teratogenic effect
*Supplements *Acne treatments *May weaken bones & contribute to osteoporosis *RDA *700 ug for women *900 ug for men *Multivitamins = 750-1500 ug |
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Beta-Carotene Toxicity
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*Not converted to active form rapidly enough to be hazardous
*Can turn people bright yellow *Builds up in fat beneath the skin |
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Beta-Carotene Conversion
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*Measured in retinol activity equivalents (RAE)
*Body makes 1 unit of retinol from 12 units of beta-carotene |
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Vitamin A in Foods
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*Preformed found only in animal foods
*Richest sources: 1. Liver 2. Fish oil *Other foods: *Milk *Cheese *Fortified cereals *Butter (some) *Eggs (some) *Margarine & low-fat & fat-free milk are fortified with vitamin A |
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Beta-Carotene in Foods
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*Bold dark orange color in fruits & vegetables:
*Carrots *Sweet potatoes *Pumpkins *Cantaloupe *Apricots *Dark green color in fruits & vegetables: *Spinach *Other greens *Broccoli *White plant foods have none |
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Vitamin D
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*Can be synthesized with help of sunlight
*Liver manufactures a precursor that migrates to skin *Sun’s rays convert to second precursor *Liver & kidneys produce active vitamin D *Is a hormone |
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Vitamin D's actions
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*Target organs:
*Intestine, kidneys, bones *Brain, pancreas, skin, reproductive organs, many cancer cells *Regulates the immune system |
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Vitamin D Deficiency
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*High blood pressure
*Rheumatoid arthritis *Type 1 Diabetes *Multiple sclerosis |
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Vitamin D's Role in Bones
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*Makes calcium & phosphorus available in the blood that bathes the bones
*Calcium & phosphorus: *Stimulates absorption from GI tract *Releases from bones to blood *Stimulates retention by the kidneys *Deficiency: rickets, osteomalacia (rickets in adults), osteoporosis |
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Vitamin D Toxicity
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*Excess vitamin D:
*Enhances calcium absorption *Produces high blood calcium *Promotes return of bone calcium into the blood *Excess calcium can precipitate in soft tissues *Forms stones (kidney) *May harden blood vessels *In excess is most toxic of all vitamins |
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Vitamin D and the Sun
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*Sun poses no toxicity risk
*Does cause premature wrinkling & risk of skin cancer *Sunscreens of (SPF) 8 & above retard synthesis of Vitamin D *Need only about 10-20 minutes of sun to make Vitamin D |
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Vitamin D in Foods
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*Animal products...
*Eggs *Liver *Butter *Some fish *Fortified milk *Fortified margarine & breakfast cereals *Fortified infant formulas *Breast milk is low in vitamin D *May need supplements *Cheese & yogurt are not fortified |
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Vitamin E
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*Fat-soluble antioxidant
*Protects PUFA & other lipids from oxidation *Protects lungs *May offer protection from heart disease |
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Vitamin E Deficiency
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*Consequences:
*Erythrocyte hemolysis *Loss of muscle coordination & reflexes *Associated with: *Diseases causing fat-malabsorption *Extremely low-fat diets *Diets of processed foods |
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Vitamin E Toxicity
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*Interfere with blood-clotting action of vitamin K
*Enhance anticoagulant medications *Research results are conflicting as to supplement safety *Tolerable Upper Level = 1,000 mg *RDA = 15 mg |
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Vitamin E in Foods
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*Widespread in foods
*Found in: *Margarine *Salad dressings *Shortenings *Wheat germ oil is rich in Vitamin E *Destroyed by heat processing & oxidation |
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Vitamin K
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*Roles:
*Blood clotting *Synthesis of several bone proteins *Can be synthesized by bacteria in intestine *Deficiency is rare *Vitamin K for newborns: *Have a sterile digestive tract *Single dose of vitamin K recommended at birth *Toxicity: *Is rare *High doses can interfere with anticoagulant medications |
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Vitamin K in Foods
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*Green leafy vegetables:
*Collards *Spinach *Brussels sprouts *Members of cabbage family *Soybean & canola oils |
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Water Soluble Vitamins
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*B Vitamins
*Thiamin *Riboflavin *Niacin *Pantothenic acid *Biotin *B6 *Folate *B12 *Vitamin C *Easily absorbed *Easily excreted *Supplements can reach toxic levels |
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Coenzymes
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*Release energy from fat, protein & carbohydrate
Thiamin Riboflavin Niacin Pantothenic acid Biotin *Assist enzymes to metabolize amino acids Vitamin B6 *Making of new cells Folate coenzyme Vitamin B12 |
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Vitamin B Deficiency
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*Deficiency of any single B vitamin seldom occurs
Beriberi: deficiency of thiamin Pellagra: deficiency of niacin *Sources of deficiencies in U.S. Poverty Ignorance, illness Alcohol abuse |
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B Vitamins
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*Interdependent Systems
All body systems depend on the B vitamins, however some systems use them to a larger extent. *Nerves & muscles depend on Thiamin *Red blood cells & GI tract cells depend on Folate |
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Enrichment of Foods
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*Adding nutrients to a food to meet a specific standard
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Fortification of Foods
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*Addition of nutrients that were not originally present or present in insignificant amounts
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Thiamin
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*Needed for all cells
Critical role in energy metabolism Critical role in nerve & muscle function *Deficiency Diet of empty kcalories, sugar or alcohol Wernicke-Korsakoff syndrome |
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Thiamin in Foods
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*Evenly distributed in foods
*Pork is the most common *Enriched or whole grain bread & cereal |
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Riboflavin
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*Facilitates energy metabolism
*Needs increase during periods of rapid growth *Is light sensitive & heat stable *Found in: Milk & milk products Dark green leafy vegetables Liver Heart Eggs |
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Niacin
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*Role in energy metabolism
*Body can make it from tryptophan *Fairly heat-resistant *Can be used as a medication to lower blood cholesterol |
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Niacin in Foods
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*Meat, poultry, & fish
*Legumes *Enriched breads & cereals *Green leafy vegetables, mushrooms, asparagus, potatoes |
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Pantothenic Acid
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*Important in energy metabolism
*Stimulates growth *Widespread in foods |
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Biotin
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*Important in energy metabolism
*Is a coenzyme that carries carbon dioxide *Participates in gene expression & cell signaling *Deficiency can come in adults fed artificially by vein *Wide-spread in foods |
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Vitamin B6 Roles
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*Stored extensively in muscle tissue
*Roles in: Protein & amino acid metabolism Synthesis of hemoglobin & neurotransmitters Release of stored glucose from glycogen Enhances immune system |
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Vitamin B6 Deficiency and Toxicity
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Deficiency
*Weakening immune response *Weakness, irritability, & insomnia *Greasy, flaky dermatitis, anemia, convulsions Toxicity *Numbness of extremities |
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Vitamin B6 Recommendation
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*Adults (19-50)
1.3 mg/day *Adults (51>70) 1.7 mg/day men 1.5 mg/day women |
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Vitamin B6 in Foods
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*Meat, fish, poultry
*A few vegetables *Some fruits |
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Folate
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*Active in cell division
*Increased need during times of growth *Deficiency causes: Anemia GI tract deterioration |
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Effects of Drugs and Alcohol on Folate
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Alcohol:
*Impairs absorption *Increases excretion Drugs: *Aspirin, oral contraception, & anticonvulsants *Impair folate status *Smoking exerts a negative effect |
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Folate in Foods
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*Liver, legumes beets & leafy green vegetables
*Oranges, orange juice, & cantaloupe *Fortified grains |
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Vitamin B12 and Folate
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*B12 needed to activate folate
*Assists folate in cell division *Deficiency of folate or B12 produces anemia |
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Vitamin B12 and the Nervous System
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*Folate masks B12 deficiency
*Causes nerve deterioration, leading to paralysis & permanent nerve damage *Concern about use of folate supplements & fortification of foods |
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Vitamin B12 and Absorption
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*Requires intrinsic factor for absorption
*Loss of intrinsic factor: Surgical removal of stomach Defective gene May need injections |
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Inositol, Choline, Carnitine
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*Are non-B Vitamins
*Serve as coenzymes in metabolism *Are abundant in foods *May be essential *Other non-B vitamins PABA Bioflavonoids Ubiquinone |
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Vitamin C's Metabolic Rules
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*Collagen formation
Matrix of the bones Material of scars “Glue” that attaches one cell to another *Antioxidant Protects water-soluble substances from oxidation Enhances iron absorption *Amino acid metabolism |
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Vitamin C Deficiency
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*Latent scurvy
Gums bleed Pinpoint hemorrhages in skin *Once diagnosed, scurvy is readily reversible 100 mg/day *Overt scurvy Muscles including heart may degenerate Skin becomes rough, brown, scaly, & dry Wounds fail to heal Fractures occur Teeth become loose Anemia & infections |
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Vitamin C Toxicity
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*Nausea
*Abdominal cramps *Diarrhea *Interference with warfarin & dicumarol *Iron overload *Safe limits = 100-300 *Recommended Intake Men = 90 mg Women = 75 mg |
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Vitamin C in Foods
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*Citrus fruits
*Cantaloupe *Strawberries *Broccoli *Brussels sprouts *Organ meats: liver & kidneys *Potatoes |
