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Chapter Eight: The Vitamins

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.

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Chapter Eight: The Vitamins

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  1. 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

  2. Vitamins, cntd. • Differentiate between active and precursor forms of Vitamin A • Describe the relationship between Vitamin and Iron Absorption

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. Precursor Form of Vitamin A

  9. 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 (bone-making 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

  10. Vitamin D Deficiency--Rickets

  11. 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

  12. Vitamin E, contd. • Sources: • Widespread in foods • Vegetable oils, fruits, vegetables and grains

  13. 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

  14. 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

  15. 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

  16. Riboflavin Source

  17. 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

  18. Spina Bifida

  19. Vitamin B Complex, cntd. • Vitamin B12 (Cyanocobalamin) • Anabolic reaction—formation of new cells, especially red blood cells • Deficiency is anemia

  20. 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

  21. Sources B Complex Vitamins

  22. 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

  23. 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

  24. 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

  25. Sources of Vitamin C

  26. Cruciferous Vegetables

  27. 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)

  28. 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

  29. 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

  30. Test Questions • The psychological desire to eat is referred to as: • Satiety • Appetite • Hunger • Obesity

  31. Obese people have much more lipoprotein lipase activity than lean people • True • False

  32. Which of the following is NOT a fat-soluble vitamin? • A • E • K • C • D

  33. Which vitamin is present only in foods of animal origin? • Riboflavin • Vitamin B12 • Pantothenic acid • The inactive form of Vitamin A

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