NTRI 2000 Chapter 8 Notes
NTRI 2000 Chapter 8 Notes NTRI 2000-001
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This 6 page Class Notes was uploaded by Abby Evans on Friday January 29, 2016. The Class Notes belongs to NTRI 2000-001 at Auburn University taught by Ramesh Jeganathan in Summer 2015. Since its upload, it has received 35 views. For similar materials see nutrition and health in Nutrition and Food Sciences at Auburn University.
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Date Created: 01/29/16
Chapter 8: Vitamins Vitamin A deficiency – xerophthalmia Vitamin D deficiency – bowed legs and rickets – children from a village in Bangladesh Vitamins are named in order of discovery (A,B,C…) Substances found not to be essential were dropped (e.g. Vitamin P) B-vitamins were thought to be one vitamin; turned out to be many (e.g. B1,B2, B3…) Vitamins as drugs: o Example, NIACIN (for lipid-lowering) o Megadose (>3-10x higher dose) Most synthesized vitamins work equally well in the body! o Vitamin E is an exception o Interestingly synthetic folic acid is 17.x more potent than natural form Definition: o Essential organic substances needed in small amounts in the diet for normal function, growth, and maintenance of the body o Produce deficiency symptoms when missing from diet o Yield no energy (no kcals) Vitamin Classification o Fat soluble vitamins A,D,E,K Not readily excreted (except vitamin K) o Water soluble vitamins B,C Generally lost from the body(except vitamins b-6 and b-12) Excreted via urine Vitamin Toxicity o Fat soluble vitamins Can accumulate in body o Water soluble vitamins Some can cause toxicity (15-100x more) o Toxicity most likely due to supplementation Functions o Facilitate energy-yielding chemical reactions o Functions as co-enzymes Preservation of Vitamins o Vitamin content decreases with: Improper storage Excessive cooking Exposure to light, heat, air, water, and alkalinity o Eat foods soon after harvest, if not freeze o Frozen veg, & fruits retain most vitamins as freshly picked ones o Blanching- destroys enzymes that breakdown vitamins, slowing down vitamin degradation Fat soluble Overview o Dissolve in organic solvents o Not readily excreted; can cause toxicity o Absorbed along with fat o Fat malabsorption may result in vitamin deficiency Cystic fibrosis Example: orlistat – weight loss drug o Transported with fat, through lipoproteins Vitamin A o Deficiency and toxicity can cause defects o Narrow optimal intake range o Retinoids or Preformed Vitamin A Only found in animal products o Provitamin A (inactive vitamin A) Can be converted to Vit. A Carotenoids (beta carotene, lutein, zeaxanthin) Found in plant products o Functions of Vitamin A Promotes Vision Night blindness, light to dark vision (adjust from bright to dim light) Prevents drying of the skin and eyes Cornea of the eye lose their ability to produce mucus- xerophthalmia (dry eye) Macular degeneration (blurred vision): adults over 65 years (legal blindness) Carotenoids – Beta carotene, lutein, zeaxanthin Centrum Silver – good source of lutein General Cell Health: Vitamin A maintains the epithelial cells. Epithelial cells serve as an important barriers to bacterial infections. Promote immune function and resistance to bacterial infection Promotes Growth by binding receptors on DNA and increase protein synthesis Cardiovascular disease prevention- Carotenoids antioxidant property – 5 servings of fruits and veggies Cancer prevention- antioxidant property carotenoid rich food reduce lung and oral cancer, dietary carotenoid found in tomatoes decrease skin cancer and prostate cancer Acne medication- (analog of vit A – Accutane, Retin-A) irritate the skin- opening of pores – peeling of skin layer. Accutane – Oral drug to treat serious acne, FDA monitored to prevent the use of thos drug during pregnancy due to high risk birth defects. iPLEDGE – mandatory distribution program required since 2006. Anti- aging – Increase the cell turnover o Toxicity of Vitamin A Large intake of Vitamin A (preformed) Over a long period Acne medications: Accutane and Retin-A Birth defects: Fetal malformation, spontaneous abortion High carotenoid intake: no toxic effects Dietary vitamin A deficiency causes some 250,000 to 500,000 children to go blind each year Vitamin D o Derived from cholesterol o Synthesized from exposure to sun 80-100% needs met Expose hands, face, arms 2-3 times a week for 5-10 minutes each time (more for darker skin) Insufficient exposure makes this a vitamin Sunscreen SPF >/= decreases synthesis 95% o Prohormone (means inactive hormone) Liver and kidney enzymes convert prohormone to active hormone o Active vitamin D acts on bone cells and intestinal cells o Functions of Vitamin D Regulates blood calcium Along with the parathyroid hormone Regulates calcium & phosphorus absorption Regulates calcium deposition in bones Influences normal cell development Linked to reduction of breast, colon, and prostate cancer Role in Bone Formation Increased calcium and phosphorous deposition in bones o Strengthens bones Rickets is the result of low vitamin D o Breastfed infants with little sun exposure th o Early 20 century, very common deficiency Osteomalacia (means soft bones) o Rickets-like disease in adults o Bone loses minerals and becomes phosphorous o Hip and bone fractures Food sources of Vitamin D Fatty fish (salmon, herring, mackerel) Fish oil Fortified milk Some fortified cereal o Toxicity Warning No toxicity from sun exposure Supplementation can be toxic, especially in infancy and childhood Upper level is 50 mcg/day Toxicity can result in: High calcium in blood (hypercalcemia) Calcium deposits in blood and organs Vitamin K (“Koagulation”) o Acts as a coenzyme, activating blood clotting factors Role in coagulation process o Synthesized by bacteria in the colon and absorbed (meets 10% requirements) o Role in calcium-binding – low vit K intake related to hip fractures o Food Sources of Vitamin K Liver Green Leafy vegetables, Broccoli, Peas, green beans Soybean oil & canola oil o Vitamin K – NOT stored efficiently in the body o 90 – 120 mcg/day o Newborns routinely injected with vitamin K Breast milk is a poor source, lack intestinal bacteria o Deficency leads to increased bleeding, internal hemmorage o Toxicity unlikely; readily excreted (no upper limit) The Mighty Antioxiadants: Vitamin E and C o Vitamin E Fat soluble vitamin in cell membranes Protects double bonds in unsaturated fats Protwctive role in cardiovascular health Not enough research to make health claim Improves vitamin A absorption Deficiency Breakdown of cell membranes Hemolysis: RBC membrane damage RDA for adults is 15 mg/day or 22 IU (DV: 30 IU) Many adults are not meeting this goal Foot Sources of Vit E Vegetable oils are good source of vit E Nuts, seeds, soybeans Animal fats & fish oil have NO vit E Susceptible populations: Pre-term infants Smokers Very-low fat diets or fat malabsorption Overview of water soluble vitamins o Subject to cooking losses o Generally readily excreted from the body o Function as coenzymes o Participate in energy metabolism o Marginal deficiency more common B vitamins o 8 B vitamins o Thiamin, riboflavin, niacin, pantothenic acid, vitamin B 6, biotin, folate, and vitamin b-12 Vitamin C o Scurvy id deficiency of Vitamin C Dr. James Lind, 1740- citrus fruits a cure for scurvy o Not synthesized for humans o Decreased absorption with high intakes o Excess excreted Diarrhea common o Sensitive to Cooking/heat Iron, copper, oxygen o Functions of Vitamin C Synthesis of collagen Found in bone, teeth, tendons Important in wound healing Iron absorption Immune functions, reduce colds? Antioxidant & free-radical scavenger Prevent certain cancers and cataract of the eye o Deficiency of Vitamin C Scurvy Deficient for 20-40 days Fatigue, pinpoint hemorrhages Bleeding gums Weakness Fractures EXTRA CREDIT o Due april 21 Functions (Vertical) Food Sources Deficiency Toxicity Daily Value o Fat soluble vitamins: A,D,E, and K (Horizontal) o Water soluble vitamins: Thiamin, Riboflavin, niacin, vitamin B6, folate, and vitamin b-12 and vitamin C o Make a table, can be handwritten or typed
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