Chapter 11 Fat Soluble Vitamins 1 Vitamin A a Precursor beta carotene b Forms Retinol supports reproduction major transport and storage form retinal active in vision retinoic acid regulated cell differentiation growth and embryonic development c Carotenoids come from plaints and convert to Vitamin A less effective than retinoids e Storage absorbed via lymph and carried to live f Major roles in Body i Vision 1 Cornea 2 Retina a Photosensitive cells b Rhodopsin pigment molecules 3 Repeated small loses of retinal a Need for replenishment need more A i taking more from the liver to replenish what s lost ii cause of blindness ii Protein synthesis and cell differentiation iii Reproduction and growth 1 Reproduction and growth a Sperm development b Normal fetal development in pregnancy c Growth of children d Bone growth 2 Antioxidant an antioxidant a Beta carotene not all is converted to A some acts as v Digestion and absorption of vitamin A aided by proteins vi Storage absorbed via lymph and carried to liver vii Transport protein Retinol binding protein RBP goes through blood ix Goblet cells cells that make mucus Without Vit A you do not have healthy mucus membrane a h Deficiency i Vitamin A status depends on a Adequacy of stores 90 store in liver b Protein status protein needed for transport of Vit of A ii Consequences of deficiency appear after 1 2 years adults sooner for kids a Risk of infectious diseases i Measles causes worse with inadequate A ii Malaria lung disease and HIV b Blindness i Night blindness Inadequate supply of retinal to retina ii Total blindness xerophthalmia lack of Vit A at cornea c Death iii Keratinization a Keratin is hard protein on hair nails i Change in shape size of epithelial cells ii Skin becomes dry rough and scaly iii Normal digestion and absorption of nutrients from GI tract falters i Weakened defenses in respiratory tract vagina inner ear and urinary tract Everything stops working i Toxicity of Vitamin A and Beta Carotene i Develops when binding proteins are loaded a Free vitamin A not bound damages cells ii Toxicity is a real possibility a Preformed Vitamin A not something that has to be converted in the body from animal sources fortified foods supplements of vitamin A or fortified foods with it or supplements iii Children are most vulnerable a They have little bodies and need less j Vitamin A and Beta Carotene Toxicity i Beta carotene a Found in many fruits and vegetables b Overconsumption from food causes yellow skin c Overconsumption from supplements 1 Antioxident becomes prooxident 2 Adverse affects seen in drinkers and smokers 3 Prooxident induuces oxidative stress ii Bone defects a May weaken bones 1 Osteoporosis 2 Interferes with vitamin D ability to maintain calcium levels iii Birth defects considered a teratogen a Cell death in the spinal cord iv Acne Retin A is related v Gene expression k Food sources i Animal sources a Liver and toxicity concerns ii Plant sources a Vitamin A precursors beta carotene veg retinoids liver fish oil butter eggs Skim milk fortified A bound with fat b Colors of food leafy greens orange yellow foods liver 2 Vitamin D a Not an essential nutrient i Body synthesizes body can make it so it s not essential 1 Sunlight 2 Precursor from cholesterol b Activation of vitamin D i Two hydroxylation reactions occur in 1 Liver 2 Kidney c Vitamin D Roles in the Body i Active form of vitamin D is a hormone 1 Binding protein carries it to target organs ii Bone growth 1 Enhances calcium and phosphorus absorption 2 Helps bones absorb nutrients from the GI tract iii Other roles 1 Enhances or suppresses gene activity d Vitamin D Deficiency i Overt signs are relatively rare Insufficiency is quite common ii Contributory factors a Dark skin breastfeeding without supplementation lack of sunlight not using fortified milk iii Creates a calcium deficiency Biggest sign bone fractures iv Rickets a Bones fail to calcify normally Bones bend beading on the ribs b Affects children v Osteomalacia a Poor mineralization of bones affects adults b Bones are soft more likely to brake flexible brittle and deformed bones are spongy big holes vi Osteoporosis a Loss of calcium from bones Results in fractures b Elderly at risk 1 Vitamin D deficiency is especially likely 2 Lose ability to make and activate Vit D 3 Drink less milk 4 Spend much of day indoors e Vitamin D Recommendation Sources i Few food sources 1 Oily fish and egg yolks 2 Fortified milk 3 fortified portabella mushrooms ii Recommendations may be insufficient 1 Recommendations are difficult to meet iii Sun exposure 1 No risk of toxicity 2 Skin color latitude season where the sun is time of day 3 Sunscreen 3 Vitamin E a Vitamin E i Four different tocopherol compounds 1 Alpha beta gamma and delta i Position of methyl group 2 Alpha tocopherol vitamin E activity in the body ii Antioxidant 1 Stop chain reaction of free radicals i Protect cells and their membranes ii Heart disease and protection of LDLs b Vitamin E Deficiency 1 Primary deficiency is rare 2 Secondary deficiency fat malabsorption 3 Effects of deficiency i Red blood cells break open ii Erythrocyte hemolysis c Vitamin E Toxicity 1 Liver regulates vitamin E concentrations 2 Toxicity is rare 3 UL is 65 times greater than recommended intake for adults 4 Extremely high doses of vitamin E i May interfere with vitamin K activity a Hemorrhage bleeding d Vitamin E Recommendations Foods 1 RDA is based on alpha tocopherol only 2 U S intakes tend to fall short of recommendations i Requirements for smokers 3 Widespread in foods i Destroyed by heat processing and oxidation 4 Highest source wheat germ oil 4 Vitamin K a Vitamin K 1 Can be obtained from non food source i Bacteria in the GI tract 2 Acts primarily in blood clotting ii Prothrombin 3 Metabolism of bone proteins iii Osteocalcin Low bone density 4 Other possible roles of vitamin K in the body b Vitamin K Deficiency 1 Primary deficiency is rare 2 Secondary deficiency i Fat absorption falters ii Some drugs distrupt Vitamin K s synthesis and action Coumadin 3 Newborn infants i Sterile intestinal tract can t synthesize Vitamin K 1 Single dose of Vitamin K is given to newborns at birth so their blood can clot c Vitamin K Toxicity 1 Not common i No adverse effects with high intakes 2 No UL 3 High doses can reduce effectiveness of anticoagulant drugs i Blood thinners ii Some one with heart disease would be taking anticoagulant drug d Vitamin K Sources 1 GI tract i Half of person s need ii Stored in
View Full Document
Unlocking...