The Fat-Soluble Vitamins: A, D, E, and KIntroductionVitamin A and Beta-CaroteneSlide 4Vitamin A and Beta-Carotene – Roles in the BodySlide 6Slide 7Slide 8Slide 9Vitamin A and Beta-Carotene – Vitamin A DeficiencySlide 11Vitamin A–Deficiency Symptom – Night BlindnessSlide 13Vitamin A-Deficiency Symptom – The Rough Skin of KeratinizationVitamin A and Beta-Carotene – Vitamin A ToxicitySlide 16Symptom of Bet-Carotene Excess – Discoloration of SkinSlide 18Vitamin A and Beta-CaroteneSlide 20Vitamin A in Selected FoodsVitamin DVitamin D Synthesis and ActivationVitamin D – Roles in the BodyVitamin D – DeficiencySlide 26Vitamin D–Deficiency Symptoms – RicketsSlide 28Vitamin D – ToxicityVitamin D – Recommendation & SourcesVitamin D Synthesis and LatitudeVitamin EVitamin E – DeficiencyVitamin E – ToxicityVitamin E – Recommendations & FoodsVitamin KVitamin K – DeficiencyVitamin K – ToxicityVitamin K – SourcesSummary- The Fat-Soluble VitaminsVitamin and Mineral SupplementsSlide 42Arguments for SupplementsWho Needs Supplements?Arguments Against SupplementsSlide 46Selection of SupplementsMisleading ClaimsRegulation of SupplementsAn Example of a Supplement LabelAlpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) TrialSlide 52Slide 53The Fat-Soluble The Fat-Soluble Vitamins: Vitamins: A, D, E, and A, D, E, and K K Chapter 11Chapter 11Dr. Alisha RovnerDr. Alisha RovnerNTDT200NTDT200Fall 2013Fall 2013IntroductionIntroduction•Differences between fat-soluble vitamins and water-soluble vitamins•Insoluble in watery GI juices so require bile for digestion and absorption•Travel through lymphatic system•Many require transport proteins in bloodstream•Excesses are stored- primarily in liver and adipose tissue•Can eat less than daily needs without ill effects•Not readily excreted so risk of toxicity is greaterVitamin A and Beta-CaroteneVitamin A and Beta-Carotene•Vitamin A, 1st fat-soluble vitamin recognized•Precursor – beta-carotene•Three different forms:•Retinol•Retinal•Retinoic acidVitamin A and Beta-CaroteneVitamin A and Beta-Carotene•Digestion and absorption of vitamin A•Several proteins participate•Storage•After absorbed via lymph system it arrives in the liver where it’s stored•Transport protein•Retinol-binding protein (RBP) picks it up from the liver and carries it in the blood•Cellular receptors for vitamin A•Cells that use vitamin A have special protein receptorsVitamin A and Beta-Carotene – Roles Vitamin A and Beta-Carotene – Roles in the Bodyin the Body•Major roles•Promoting vision•Participating in protein synthesis and cell differentiation, thereby maintaining the health of epithelial tissues and skin•Supporting reproduction and growthVitamin A and Beta-Carotene – Roles Vitamin A and Beta-Carotene – Roles in the Bodyin the Body•Retinol•Supports reproduction•Major transport and storage form•Retinal•Active in vision•Retinoic acid•Regulates cell differentiation, growth, and embryonic developmentVitamin A and Beta-Carotene – Roles Vitamin A and Beta-Carotene – Roles in the Bodyin the Body•Vision•Plays indispensable roles in eye•Helps maintain cornea •Participates in conversion of light energy into nerve impulses at the retinaVitamin A and Beta-Carotene – Roles Vitamin A and Beta-Carotene – Roles in the Bodyin the Body•Protein synthesis & cell differentiation•Epithelial cells (cells on surface of skin and mucous membranes)•Helps protect against skin damage from sunlight•Promotes differentiation of epithelial cells and goblet cells (secrete mucous)Vitamin A and Beta-Carotene – Roles Vitamin A and Beta-Carotene – Roles in the Bodyin the Body•Reproduction and growth•In men- participates in sperm development•In women- supports normal fetal development•Growth of children•Bone remodeling•Antioxidant•Beta-carotene serves primarily as vitamin A precursorVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A DeficiencyVitamin A Deficiency•Vitamin A status•Depends mostly on adequacy of stores•90% stored in liver•Depends on protein status because RBP serves as vitamin’s transport carrier•Consequences of deficiency•Risk of infectious diseases•Blindness•DeathVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A DeficiencyVitamin A Deficiency•Infectious diseases•Measles severity •Malaria, lung diseases, and HIV•Night blindness•Inadequate supply of retinal to retina•Blindness (xerophthalmia)•Lack of vitamin A at the cornea•Develops in stagesVitamin A–Deficiency Symptom – Vitamin A–Deficiency Symptom – Night BlindnessNight BlindnessVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A DeficiencyVitamin A Deficiency•Keratinization•Change in shape & size of epithelial cells•Skin becomes dry, rough, and scaly•Normal digestion and absorption of nutrients from GI tract falters•Weakened defenses in respiratory tract, vagina, inner ear, and urinary tractVitamin A-Deficiency Symptom – The Vitamin A-Deficiency Symptom – The Rough Skin of KeratinizationRough Skin of KeratinizationVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A ToxicityVitamin A Toxicity•Develops when binding proteins are loaded•Free vitamin A damages cells•Toxicity is a real possibility•Preformed vitamin A from animal sources•Fortified foods•Supplements•Children are most vulnerableVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A ToxicityVitamin A Toxicity•Beta-carotene•Found in many fruits and vegetables•Inefficient conversion•Overconsumption from food•Yellow skin•Overconsumption from supplements•Antioxidant becomes prooxidant•Alcohol consumption and tobacco useSymptom of Bet-Carotene Symptom of Bet-Carotene Excess – Discoloration of SkinExcess – Discoloration of SkinVitamin A and Beta-Carotene – Vitamin A and Beta-Carotene – Vitamin A ToxicityVitamin A Toxicity•Bone defects•May weaken bones•Osteoporosis•Interferes with vitamin D•Birth defects•Cell death in the spinal cord•Acne•Vitamin A relative – Retin-AVitamin A and Beta-Carotene Vitamin A and Beta-Carotene •Recommendations•Expressed as retinol activity equivalents (RAE)•Supplements often measured in International Units (IU)Vitamin A and Beta-Carotene Vitamin A and Beta-Carotene •Food
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