Dr. Greene Week 9 Notes
Dr. Greene Week 9 Notes NTRI 2000-002
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This 7 page Class Notes was uploaded by Rachel Ferrell on Wednesday April 6, 2016. The Class Notes belongs to NTRI 2000-002 at Auburn University taught by Michael Winand Greene in Fall 2015. Since its upload, it has received 23 views. For similar materials see Nutrition and Health in Nutrition and Food Sciences at Auburn University.
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Date Created: 04/06/16
Rachel Ferrell NTRI 2000 3/28/-‐4/1 Chapter 8: Cont: Vitamin A Deficiency: • Leading cause of blindness worldwide • Eye cells affected o Inability to adjust to dim light; leads to night blindness • Xerophthalmia= hardening of cornea and drying of the surface of eye o Can result in blindness • North Americans→low risk for Vitamin A deficiency o Typical diet contains enough Vit. A • Worldwide→1/3 of children suffer from Vitamin A deficiency o Solutions? § Promote breastfeeding § Giving Vitamin A mega-‐doses twice a year § Fortification of sugar and margarine Getting Enough Vitamin A and Carotenoids: • Performed Vitamin A: o Liver, fish, fish oils, fortified milk, butter, yogurt, eggs • Carotenoids: o Dark green/yellow vegetables o Cooking improves bioavailability • RDA→expressed in retinol activity equivalents (RAE) o Both performed and carotenoid sources (active form of Vitamin A) o Typical American diets are sufficient o Supplements of Vitamin A are unnecessary Excess Vitamin A: • Performed o Linked to birth defects (teratogens) o Liver toxicity • Carotenoids o No toxic effects o Side effect→ Hypercarotenemia= skin turns yellow/orange Vitamin D: • Fat soluble • Not just a vitamin; also a hormone • Requires skin, livers, and kidneys working together • Body can make more Vitamin D when exposed to UV light o Ability to make vitamin D depends on exposure time, skin color, age, time of day, season, and location • Functions: o Regulates blood calcium and bone metabolism § Works with parathyroid hormone o Helps regulate calcium and phosphorus absorption from intestine o Regulates deposition of Calcium in bone o Regulates Calcium excretion from kidney o Helps in decrease of cancer risk § Skin, colon, prostate, ovary, breast Vitamin D Deficiency: • Rickets (bone disease) o In children o Bow legs, enlarged head, joints, ribcage, deformed pelvis • Osteomalacia o In adults o Softening of bones o Leads to fracture of hips and other bones Excess Vitamin D: • UL= 50 mg per day • Causes Calcium buildup deposits in small tissues • Cant happen from too much exposure to sunlight Vitamin D in Foods: • Fatty fish • Fortified milk/yogurt • Some cereals Vitamin E: • Fat soluble • Family of compounds called Tocopherols o Alpha Tocopherols= main form in body o Gamma Tocopherols= found in foods • Function→ acts as fat soluble antioxidant • Found mostly in cell membranes • Antioxidant role: o Oxidizing agents= want electrons § Ex. double bonds of unsaturated fatty acids in phospholipids o Oxidizing agents→create free-‐radicals o Vitamin E→has electrons it can give up to oxidizing agents o Result→protects components of cell Vitamin E Deficiency: • Can cause cell membranes to break down • Can happen in RBC→hemolysis o Cells cant carry oxygen o Can lead to anemia • Premature infants at high risk • Smokers at higher risk Excess Vitamin E: • UL= 1000mg per day • Can interfere with clotting, leading to hemorrhage • Higher risk people: o People on anticoagulants o People on high doses of asprin o People with Vitamin K deficiency Vitamin E in Foods: • Plant oils (salad dressing, mayo) • Cereals • Dry roasted sunflower seeds/almonds • Fruits/veggies Vitamin K: • Vital for blood clotting • Activates proteins present in bone, muscle, and kidneys to give Calcium binding ability to these organs • Poor Vitamin K intake o Associated with hip fractures in women • About 10% of our Vitamin K in body made by bacteria living in our GI tract • Babies→Vitamin K supplement at birth to ensure blood clotting • Vitamin K in Foods: • green, leafy vegetables o kale, spinach, asparagus, broccoli • oils o soybean, canola • Toxicity→no risk, no UL Water Soluble Vitamins: • Includes: o Vitamin C o B Vitamins § Vitamin B6 § Vitamin B12 § Folate § Thiamin § Riboflavin (B2)/Niacin(B3) § Pantothenic Acid Vitamin C: • Compounds with antiscorbutic activity • Dietary form= ascorbic acid • Similar in structure to glucose • Essential for humans and other species • Foods: o Citrus fruits, green peppers, brussel sprouts, strawberries, tomatoes, fortified drinks o Can also be used in foods as a preservative • Stability: o Rapidly lost by processing/ cooking food o Unstable in the presence of heat, iron, copper, or oxygen o This is common for all water soluble vitamins • Functions: o 1.) Formation of collagen § strengthens structural tissues by increasing cross connections between amino acids o 2.) Formation of other compounds § Carnitine § Serotonin § Norepinephrine o 3.) Antioxidant § can readily accept/donate electrons B-‐ Vitamins: • Occurs in many of the same foods o Lack of 1 B-‐Vitamin usually means you are lacking in other B-‐Vitamins • Deficiency symptoms: o Brain/nervous system o Skin o GI tract • Several B-‐Vitamins are in whole grains, but are removed during the milling process (which is what is done to help preserve food) • To counter these losses, flour in U.S. enriched with 4 B-‐Vitamins o Thiamin o Riboflavin o Niacin o Folate • Vitamin B-‐6 o Also called pyridoxine o Needed for activity of many enzymes § Help in carb, protein, and fat metabolism o Particularly important in amino acid metabolism § Aids in transferring nitrogen group § Allows us to make nonessential amino acids o Necessary for synthesis of neurotransmitters § Allows nerve cells to communicate o Important in synthesis of hemoglobin § To make RBC/WBC § Necessary for conversion of tryptophan to niacin • Vitamin B-‐12 o Contains mineral Cobalt o Must bind to intrinsic factor (made by stomach) in order to be absorbed o Defective B12 absorption→common in older people § Because they have low intrinsic factor o Found in animal products § Meat, milk, poultry, seafood, eggs, cereals o Functions: § Required to convert folate to its active form § Maintains myelin sheaths on neurons • Destruction of myelin sheaths→ paralysis or death o Deficiency: § Pernicious anemia • “Pernicious” = leading to death • Symptoms= weakness, tingling of extremitites • Infants of vegans at risk • Folate o Folic acid= synthetic form o Single Carbon supplier or donor o Acts as a coenzyme § Helps for DNA § Metabolizes various amino acids and their derivatives o Deficiency § Bone marrow produces immature RBC (megaloblasts) § Megaloblastic anemia • Symptoms: inflammation of tongue, mental confusion, depression, problems with nervous system § 10% of people have genetic defect in metabolism of folate • therefore they need to consume double the RDA in Folate § relates to the development of the neural tube→defects in the fetus • Spina bifida o Affects about 2,000 infants per year o Neural tube should close within the first 28 days of pregnancy o Most women don’t even know they’re pregnant yet o All women of childbearing age should have enough folate o RDA= 400 micrograms per day o If pregnant= 600 micrograms per day o Foods: § Green, leafy vegetables § Susceptible to destruction by heat • Thiamin (B ) 1 o Helps release energy from carbs and certain amino acids o Deficiency: § Beriberi= disease relating to weakness of nervous system o Foods: § No UL § Found in pork products, whole grains, cereals, enriched grains • Riboflavin (B ) 2 and Niacin (B 3 o Both aid in energy metabolism o Act as coenzymes § Riboflavin= FAD § Niacin= NAD • Pantothenic Acid o Aids in energy metabolism o Coenzyme-‐A o Deficiency is unlikely Chapter 9: Water and Minerals: Water: • Life can’t exist without water • Water= solvent for chemical reactions in the body o Allows for chemical reactions to take place • Water= 50-‐70% of body’s weight • Can’t survive long without water Fluid Compartments: • Intracellular= water inside the cell (63%) • Extracellular= water outside the cell (37%) • Total of these = 40L • Water can move (diffuse) between compartments • How is this controlled? o Ions= minerals with an electrical charge § Control movement of water b/w compartments § Also called electrolytes o Osmosis= movement of water across a semipermeable membrane Functions of Water: • Solvent for chemical reactions in body • Body temp regulation→sweat • Helps remove waste products o Waste dissolves in water • Cushions and lubricates o Knees/joints, saliva, bile Water Balancing Act: • Water is not stored • Regulated by nervous, endocrine, digestive and urinary systems • Not enough water? o 1-‐2% loss: thirst mechanism occurs o 4% loss: muscles lose strength and endurance o 20% loss: coma or death • How does body conserve water? o Antidiuretic Hormone (ADH) § Released by pituitary gland § Communicates with kidney to conserve water o Aldersterone § Released from adrenal gland (right by kidneys) when blood volume decreases § Communicates with kidney to conserve water • Can thirst be ignored? o Yes o atheletes→weigh before and after workout to measure water loss o sick children o older people infants o all of these groups don’t feel thirsty even if they are low on water • Too much water? o Too much in short period of time= water intoxication o Dilutes sodium levels→ hyponatremia § Symptoms: nausea, vomiting, headache, muscle weakness, convulsions Minerals: • Major minerals: >100 mg/day • Trace minerals: <100 mg/day Mineral Bioavailability: • =How much we take in from food sources • Depends on o 1.) Amount of food o 2.) Ability to absorb it • Therefore, the amount of minerals in a food doesn’t actually match how much of it our body absorbs • Bioav. Of Minerals from plants: o Depends on the soil its grown in o May be bound by dietary fibers and other molecules • Bioav. Of Minerals from animals: o Not dependent on soil like plants o Absorbed better than plant sources § Because fewer binders and dietary fibers Mineral Binders: • Oxalates o Spinach o Binds Calcium • Phytates o Grains o Binds Calcium, Iron, Zinc, and others • Mineral-‐Mineral interactions o Ca/Fe o Zn/Cu • Vitamin-‐Mineral interactions o Vit. C→improves iron absorption o Vit. D→improves Ca absorption Mineral Toxicity: • Can be toxic in high levels, especially trace minerals • Problem is usually with supplements
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