Vitamins Lectures (10 & 11) - MISR UNIVERSITY

Title: lectures (10 & 11) Vitamins Present By: Prof.Ingy Badawy  ‫رؤية كلية التكنولوجيا الحيوية‬ ‫أن تكون كلية معتمدة أكاديميا ً و رائدة‬ ‫فى مجاالت التكنولوجيا الحيوية على‬ ‫المستوى المحلى واإلقليمى والدولى‬  ‫رسالة كلية التكنولوجيا الحيوية‬ ‫تلتزم كلية التكنولوجيا الحيوية ‪ -...

Title: lectures (10 & 11) Vitamins Present By: Prof.Ingy Badawy  ‫رؤية كلية التكنولوجيا الحيوية‬ ‫أن تكون كلية معتمدة أكاديميا ً و رائدة‬ ‫فى مجاالت التكنولوجيا الحيوية على‬ ‫المستوى المحلى واإلقليمى والدولى‬  ‫رسالة كلية التكنولوجيا الحيوية‬ ‫تلتزم كلية التكنولوجيا الحيوية ‪ -‬جامعة مصر للعلوم‬ ‫والتكنولوجيا الخاصة بتخريج أخصائى تكنولوجيا حيوية‬ ‫طبقا ً للمعايير األكاديمية القياسية المعتمدة يلبى احتياجات‬ ‫سوق العمل المحلى واإلقليمى فى القطاعات الطبية‬ ‫والصيدلية و الزراعية و البيئية وإجراء بحوث علمية‬ ‫مبتكرة وتقديم خدمات مجتمعية واستشارات علمية فى إطار‬ ‫قيم إرتقائية‪.‬‬ ILOs: Recognize vitamins, structure, functions and their deficiency manifestations. Demonstrate a systematic understanding of the processes and mechanisms of life, from molecules to cells Relate the biochemical analysis to the human health Distinguish the effect of vitamins deficiency. Outlines Fat- soluble vitamins Vitamin A Vitamin D Vitamin E Vitamin K Water –soluble vitamins Vitamin C Vitamin B complex The Fat-Soluble Vitamins A, D, E, and K The Fat-Soluble Vitamins Vitamin A And Beta-Carotene Retinoids and carotenoids Vitamin A activity Vitamin A And Beta-Carotene Vitamin A And Beta-Carotene Retinol-binding protein (RBP) Vitamin A And Beta-Carotene Roles in the body Vitamin A in vision  Roles in the body Vitamin A in protein synthesis and cell differentiation Vitamin A And Beta-Carotene Roles in the body Vitamin A in reproduction and growth Beta-carotene as an antioxidant Absorption of Vitamin A Retinoids Retinyl esters broken down to free retinol in small intestine - requires bile, digestive enzymes, integration into micelles Once absorbed, retinyl esters reformed in intestinal cells 90% of retinoids can be absorbed Carotenoids Absorbed intact, absorption rate much lower Intestinal cells can convert carotenoids to retinoids Transport and Storage of Vitamin A Liver stores 90% of vitamin A in the body Reserve is adequate for several months Transported from intestinal cells to the liver Transported from the liver to target tissue as retinol via retinol-binding protein, which is bound to transthyretin Excretion of Vitamin A Not readily excreted Some lost in urine Kidney disease and aging increase risk of toxicity because excretion is impaired Functions of Vitamin A: Vision Retinal turns visual light into nerve signals in retina of eye Retinoic acid required for structural components of eye Cones in the retina Responsible for vision under bright lights Translate objects to color vision Rods in the retina Responsible for vision in dim lights Translate objects to black and white vision The Visual Cycle Functions of Vitamin A: Growth and Differentiation of Cells Retinoic acid is necessary for cellular differentiation Important for embryo development, gene expression Retinoic acid influences production, structure, and function of epithelial cells that line the outside (skin) and external passages (mucus forming cells) within the body Functions of Vitamin A: Immunity Deficiency leads to decreased resistance to infections Supplementation may decrease severity of infections in deficient person Possible Carotenoid Functions Prevention of cardiovascular disease Antioxidant capabilities ≥5 servings/day of fruits and vegetables Cancer prevention Antioxidant capabilities Lung, oral, and prostate cancers Studies indicate that vitamin A-containing foods are more protective than supplements In general, foods rich in vitamin A and other phytochemicals are advised rather than supplements Vitamin A in Foods Preformed Liver, fish oils, fortified milk, eggs, other fortified foods Provitamin A carotenoids Dark leafy green, yellow-orange vegetables/fruits RDA for Vitamin A for Adults 900 RAE for men 700 RAE for women Average intake meets RDA Much stored in the liver Vitamin A supplements are unnecessary No separate RDA for carotenoids Deficiency of Vitamin A Most susceptible Consequences: populations: Night blindness Preschool children with Decreased mucus low F&V intake production Urban poor Decreased immunity Older adults Alcoholism Bacterial invasion of the Liver disease (limits eye storage) Irreversible blindness Fat malabsorption Poor growth Upper Level for Vitamin A 3000 μg retinol Hypervitaminosis A results from long-term supplement use (2 – 4 x RDA) Toxicity Fatal dose (12 g) Toxicity of Vitamin A Acute – short-term megadose (100 x RDA); symptoms disappear when intake stops GI effects Headaches Blurred vision Poor muscle coordination Toxicity of Vitamin A Chronic – long-term megadose; possible permanent damage Bone and muscle pain Loss of appetite Skin disorders Headache Dry skin Hair loss Increased liver size Vomiting Toxicity of Carotenoids Not likely, as rate of conversion of carotenoids to retinoic acid by liver is slow and efficiency of absorption of carotenoids decreases as intake increases Hypercarotenemia High amounts of carotenoids in the bloodstream Excessive consumption of carrots/beta-carotene supplements Skin turns a yellow-orange color Content Review What are the functions of vitamin A? What are the two forms of vitamin A and in what foods can they be found? How does vitamin A help with night vision? What are the effects of a diet that is deficient in vitamin A? What are the effects of a diet that is toxic in vitamin A? Vitamin D Fat-soluble vitamin Sources Foods Naturally found in very few foods Added to many foods on the market Supplements Sunlight Vitamin D Daily Recommended Intake Current minimum intake recommendations Birth-50 years = 200 IU 51-70 years = 400 IU 71+ years = 600 IU Food Sources of Vitamin D 3 oz smoked salmon = 583 IU 3 oz light tuna, canned in oil = 229 IU 1 large, whole egg = 29 IU Foods Fortified with Vitamin D 8 oz skim milk = 115 IU 8 oz orange juice = 100 IU 1 cup Cheerios = 40 IU ½ cup yogurt = 40 IU Vitamin D Other names Calciferol 1,25-dihydroxy vitamin D (calcitriol) Animal version: vitamin D3 or cholecalciferol Plant version: vitamin D2 or ergocalciferol Precursor is the body’s own cholesterol Vitamin D Functions Many uses in the body Promotes absorption of calcium from the small intestine Maintain blood levels of calcium and phosphate for bone formation, mineralization, growth, and repair Improves muscle strength and immune function Reduces inflammation Vitamin D Deficiency At risk populations Breastfed infants Older adults People with limited sun exposure Darker skin pigments Vitamin D Related Diseases Rickets Osteomalacia Osteoporosis Vitamin D Deficiency symptoms: rickets in children Inadequate calcification, resulting in misshapen bones (bowing of legs) Enlargement of ends of long bones (knees, wrists) Vitamin D Deficiency symptoms: rickets in children (continued) Delayed closing of fontanel, resulting in rapid enlargement of head Vitamin D Deficiency symptoms: rickets in children (continued) Lax muscles resulting in protrusion of abdomen Muscle spasms Deficiency symptoms: osteomalacia in adults Loss of calcium, resulting in soft, flexible, and deformed bones Vitamin D Deficiency symptoms: osteomalacia in adults (cont.) Progressive weakness Pain in pelvis, lower back, and legs Toxicity disease: hypervitaminosis D Vitamin D Toxicity symptoms Elevated blood calcium Calcification of soft tissues (blood vessels, kidneys, heart, lungs, tissues around joints) Frequent urination Vitamin D and Cancer Roles in prevention of Colon cancer Breast cancer Vitamin D and Cancer How it prevents Promotes cellular differentiation Decreases cancer cell growth Stimulates cell deaths  True or False. Vitamin D is not necessary for Calcium to be absorbed in the body.  True or False. Vitamin D is not necessary for Calcium to be absorbed by the body. Questions? Mmm…. Vitamin D drops! Vitamin E Other name: alpha-tocopherol 2000 RDA Adults: 15 mg/day Upper level for adults: 1000 mg/day Chief function in the body Antioxidant (stabilization of cell membranes, regulation of oxidation reactions, protection of polyunsaturated fatty acids and vitamin A) Vitamin E Significant sources Polyunsaturated plant oils (margarine, salad dressings, shortenings) Leafy green vegetables, wheat germ, whole grains, liver, egg yolks, nuts, seeds Vitamin E Easily destroyed by heat and oxygen Deficiency symptoms Red blood cell breakage Nerve damage Toxicity symptoms Augments the effects of anticlotting medication Vitamin K Other names Phylloquinone Menaquinone Menadione Naphthoquinone 2001 AI Men: 120 g/day Women: 90 g/day Vitamin K Chief functions in the body Synthesis of blood-clotting proteins and bone proteins that regulate blood calcium  Vitamin K Significant sources Bacterial synthesis in the digestive tract Liver Leafy green vegetables, cabbage-type vegetables Milk Vitamin K Deficiency symptoms Hemorrhaging Toxicity symptoms None known The Fat-Soluble Vitamins - In Summary Interactions with each other Interactions with minerals Antioxidant Nutrients In Disease Prevention Free radicals and disease Oxidative stress Defending against free radicals Oxidants and antioxidants Antioxidant Nutrients In Disease Prevention Antioxidant Nutrients In Disease Prevention Defending against cancer Defending against cardiovascular disease The Water-Soluble Vitamins Overview of Water-Soluble Vitamins Dissolve in water Generally readily excreted Subject to cooking losses Function as a coenzyme Participate in energy metabolism 50-90% of B vitamins are absorbed Marginal deficiency more common Enrichment Act of 1941 and 1998 Many nutrients lost through milling process of grains Grain/cereal products are enriched Thiamin, riboflavin, niacin, folate, iron Whole grains contain original nutrients Enriched grains still deficient in B-6, magnesium and zinc Vitamin B 1- Thiamin Contains sulfur and nitrogen group Destroyed by alkaline and heat Coenzyme: Thiamin pyrophosphate (TPP) Food Sources of Thiamin Wide variety of food White bread, pork, hot dogs, luncheon meat, cold cereal Enriched grains/ whole grains Thiaminase found in raw fish Vitamin B1 - Thiamine Functions Essential for release of energy from carbohydrates Necessary for appetite and good health Needed for normal functioning of nervous system Absorption, Transport, Metabolism of Thiamin Absorbed in the jejunum by a carrier-mediated system Transported by RBC in the blood Excess quickly excreted in the urine RDA For Thiamin 1.1 mg/day for women 1.2 mg/day for men Most exceed RDA in diet Surplus is rapidly lost in urine; non toxic Who is at Risk For Deficiency? Poor Alcoholics Diet consisting of highly processed foods Deficiency of Thiamin Occurs where rice is the only staple Dry beriberi Weakness, nerve degeneration, irritability, poor arm/leg coordination, loss of nerve transmission Wet beriberi Edema, enlarge heart, heart failure  Vitamin B2 -Riboflavin Functions Deficiency Metabolism of carbohydrates, proteins Loss of appetite and fats Swollen tongue, cracked lips, eye infection, dermatitis Growth, repair, development of body tissues - healthy skin, eyes and tongue The principal growth promoting factor in the vitamin B complex Food Sources of Riboflavin Milk/products Enriched grains Liver Yeast extract Sensitive to uv radiation (sunlight) Stored in paper, opaque plastic containers Absorption, Transport, & Metabolism of Riboflavin HCL in the stomach release riboflavin from its bound forms Absorption Active or facilitated transport during low to moderate intake Passive absorption during high intake Increase with intake Transported by a protein carrier in the blood Functions of Riboflavin Accepts electrons Electron Transport Chain FAD FADH2 Succinate Fumarate Citric Acid Cycle RDA for Riboflavin 1.1 mg/day for women 1.3 mg/day for men Average intake is above RDA Toxicity not documented Who is at Risk For Deficiency? Rare Low milk/dairy intake Alcoholics Deficiency of Riboflavin Ariboflavinosis dermatitis, stomatitis, eye disorder, throat disorder, nervous system disorder Occurs within 2 months Usually in combination with other deficiencies Vitamin B -Niacin (Nicotinic acid) Functions Deficiency Metabolism of carbohydrates, Fatigue, depression, irritability proteins and fats Beri-beri - disease of Needed for normal functioning nervous system of nervous system Common in countries where polished rice is staple food Food Sources of Niacin Mushrooms Enriched grains Beef, chicken, turkey, fish Heat stable; little cooking loss Vitamin B -Niacin (Nicotinic acid) *Related to protein Properties *RDA intake Water soluble 15 - 20mg per day Stable to heat Fairly stable to acids/alkalis 80 -90% loss in milling Absorption, Transport and Storage of Niacin Readily absorbed from the stomach and small intestine Absorption: active transport and passive diffusion Transported from the liver to all of the tissues where it is converted to the coenzymes Niacin as a Medicine 75-100 x RDA can lower LDL and TG and increase HDL Slow/ reverse progression of atheroscelerosis with diet and exercise Toxicity effects Flushing of skin, itching, nausea, liver damage  Vitamin B6 -Pyridoxine Functions Deficiency Protein metabolism Tiredness and Fatigue, irritability Involved in formation of Premenstrual tension haemoglobin, hormones and Infants may suffer structural proteins convulsions if there is Healthy development of deficiency nervous system Vitamin B6 -Pyridoxine Sources Meat l Eggs Yeast extracts Fish Cereals Vitamin B6 -Pyridoxine Properties RDA Water soluble 2mg per day Reasonably heat stable Sensitive to high temperatures, oxygen, milling and processing Vitamin B12 - (Cyano) Cobalamin Functions Deficiency Red blood cell formation Pernicious anaemia Nervous system - maintains Nerve degeneration myelin sheath around nerves Helps treat pernicious anaemia Vitamin B12 - (Cyano) Cobalamin Sources Meat, Offal Fish Cheese No B12 in plant foods - Vegans, vegetarians risk of deficiency Vitamin B12 - (Cyano) Cobalamin RDA Properties Water soluble 3-4 µg per day Heat stable up to 100°C Affected by strong acids/alkalis Affected by light Vitamin B -Folic Acid Functions Deficiency Red blood cell formation Fatigue in mild cases Essential for synthesis of DNA and Anaemia in severe cases RNA Neural tube defects Development of brain, spinal cord and skeleton in foetus Important to take folic Reduces risk of neural tube acid prior to conception and vital during first 3 defects e.g. spina bifida months pregnancy May play role preventing heart attacks, strokes and cancer Vitamin B -Folic Acid Sources Offal Fortified cereals Green leafy vegetables Potatoes bread Milk Wheatgerm Vitamin B -Folic Acid Properties RDA Water soluble 300 µg per day Unaffected by acids More during Sensitive to light and pregnancy oxidation Vitamin C Ascorbic acid (reduced form), dehydroascorbic acid (oxidized form) Synthesized by most animals (not by human) Absorbed by a specific energy dependant transport system Decrease absorption with high intakes Excess excreted Vitamin C -Ascorbic Acid Functions Deficiency Formation of connective tissue, Weakening of connective collagen tissue Critical to immune system Susceptibility to infection Helps absorption of iron Incomplete iron Prevents scurvy absorption Promotes healing of wounds and Delayed healing of healthy blood vessels wounds Acts as antioxidant, protects HDL cholesterol Vitamin C -Ascorbic Acid Sources Orange, green peppers, kiwi, citrus fruits, strawberries, spinach,broccolli Collagen Synthesis (Fig. 10-12) Antioxidant Can donate and accept hydrogen atoms readily Water-soluble intracellular and extracellular antioxidant Must be constantly enzymatically regenerated Needs are higher for smokers RDA for Vitamin C 90 mg/day for male adults 75 mg/day for female adults +35 mg/day for smokers Average intake ~72 mg/day Fairly nontoxic (at