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Chapter Eight: The Vitamins Define vitamins and identify their characteristics Differentiate between the two classes of vitamins Name the fat-soluble vitamins Major functions Deficiency results Significant food sources of each Vitamins, cntd. Differentiate between active and precursor forms of Vitamin A Describe the relationship between Vitamin and Iron Absorption Characteristics of Vitamins Occur in food in much smaller amounts No energy contributions—no kcalories Help and facilitate body processes Necessary for health but not CURE--ALLS Vitamins Defined Potent, essential, non-caloric, organic nutrients Measured in milligrams or micrograms Assist enzymes in the release of energy from the energy nutrients Fat soluble and Water soluble forms Bioavailability—quantity provided and amount absorbed Fat-Soluble Vitamins Vitamins A, D, E, and K Stored in Liver and Fatty Tissues Excess not excreted—can be toxic Travel in the blood with protein Not necessary to replenish daily Vitamin A (Retinol and Beta-Carotene) Metabolic Functions--Antioxidant Vitamin A, cntd. Vision—part of the pigment of the eye that allows eye to adjust to changing light levels Health of skin and linings of organs—health of epithelial cells that secrete mucus Defense against infection Toxicity: animal sources and high dosage supplements Vitamin A, contd. Active vs. Precursor form Active form (retinol) found in animal sources—fat of animals Precursor form (beta-carotene) found in deep green and dark yellow fruits and vegetables—activate only when needed Deficiency: Night Blindness and dryness of epithelial cells Precursor Form of Vitamin A Vitamin D (Calciferol) Not totally essential because the body can make it from sunlight on the skin Functions: Makes calcium and phosphorus available in blood to harden bones (bonemaking and maintenance team) Deficiencies: Rickets in children and Osteomalacia mostly in child-bearing women Osteoporosis—impairs calcium absorption Sources: Eggs, liver, fish oils, and fortified milk Vitamin D Deficiency--Rickets Vitamin E (Tocopherol) Function: Anti-oxidant—defends against oxidation—especially polyunsaturated fatty acids Heart health and protection against fibrocystic disease Deficiency: Erythrocite hemolysis— breaking open of red blood cells Toxicity: above 800 mg/RDA 8-10 mg Vitamin E, contd. Sources: Widespread in foods Vegetable oils, fruits, vegetables and grains Vitamin K Synthesis is possible in the intestinal tract, but not sole source of it—not found in sterile GI tract (newborns) Antibiotics can interfere with synthesis Function: necessary for normal blood clotting Sources: green leafy vegetables, cabbage family, liver, meats, milk, eggs, cereal and fruits Water-Soluble Vitamins No accumulation in body tissues from foods—large doses of supplements can be toxic Easily absorbed and excreted in urine when there is excess Need good sources daily Vitamin B Complex Coenzymes involved in catabolic and anabolic reactions in the body Thiamin(B1), Niacin(B3), Riboflavin(B2), Pantothenic Acid & Biotin Involved in catabolic reactions Needed for the release of energy from the energy nutrients Riboflavin Source Vitamin B Complex, contd. Vitamin B6 Anabolic reaction—synthesis of nonessential amino acids Can minimize heart disease risk Folate Anabolic reaction—new cell synthesis—especially of nervous system and spinal cord of developing fetus Deficiency during pregnancy can lead to spina bifida—incomplete formation of spinal column Spina Bifida Vitamin B Complex, cntd. Vitamin B12 (Cyanocobalamin) Anabolic reaction—formation of new cells, especially red blood cells Deficiency is anemia Vitamin B Complex, cntd. Deficiency diseases Thiamin—Beriberi Niacin--Pellagra Fortification and Enrichment of staple foods—especially cereals and grain products has reduced deficiencies of B Vitamins Sources B Complex Vitamins B Vitamin Complex, cntd. Good sources are widespread in foods— whole foods best sources Light and heat sensitive—can be lost in cooking liquid Folate: Best sources are liver, legumes, and green leafy vegetables (foliage) Vitamin B12: Only available in animal products Vitamin C (Ascorbic Acid) Function: Necessary for the formation of the protein collagen—protein of connective tissue (wound healing); also an antioxidant for water solubles Deficiency: Scurvy—bleeding gums, pinpoint hemorrhages, bruising easily, failure of wounds to heal RDA: 75 -100 mg Increases during pregnancy and lactation Vitamin C, cntd. Stress, infections and smoking increase needs up to 100 mg Oral contraceptives increase needs Sources: Fruits and Vegetable groups only—especially citrus fruits, strawberries, and cruciferous vegetables Sources of Vitamin C Cruciferous Vegetables Vitamin Supplements—Are They Necessary? Good diet including a variety of foods should supply vitamins & minerals needed Those who may need them Low kcalorie dieters Depressed appetite—illness, age Illnesses that impair absorption Heavy blood losses—menstruation (Iron) Vitamin Supplements, cntd. During pregnancy and lactation—especially iron and folate Strict (vegan) vegetarians Newborn infants Recovery from infection or surgery Breast fed infants Best if prescribed by R.D. or M.D.— multivitamin usually safe Phytochemicals Found in foods—impart tastes, aromas, colors, etc. Act as antioxidants and suppress diseases Diets rich in whole grains, legumes, vegetables and fruits can be protective against heart disease and cancer Eat colorful foods—orange, red and green Test Questions The psychological desire to eat is referred to as: Satiety Appetite Hunger Obesity Obese people have much more lipoprotein lipase activity than lean people True False Which of the following is NOT a fatsoluble vitamin? A E K C D Which vitamin is present only in foods of animal origin? Riboflavin Vitamin B12 Pantothenic acid The inactive form of Vitamin A