7 The Vitamins Copyright 2016 Cengage Learning All

7 The Vitamins Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

LEARNING OUTCOMES 1 Summarize the historical achievements related to the discovery of vitamins. 2 Discuss factors that the water-soluble vitamins have in common. 3 Understand the functions and sources of the B vitamins. 4 Describe the functions and sources of vitamin C. 5 Understand factors that the fat-soluble vitamins have in common. Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2

LEARNING OUTCOMES 6 Describe the functions and dietary sources of vitamin A and the carotenoids. 7 Understand the functions and sources of vitamin D. 8 Understand the functions and sources of vitamins E and K. 9 Describe the advantages and disadvantages associated with dietary supplements versus food. Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3

What Do Scientists Know about Vitamins? • Organic compounds • Classification • Water-soluble • Fat-soluble • 13 essential vitamins • Letter designations • Common names • Chemical names Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4

Water-Soluble Vitamins • Commonalities among water-soluble vitamins • All dissolve in water • Body generally absorbs and transports them in a similar way - Bioavailability • Overconsumption generally does not lead to toxic effects Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5

Water-Soluble Vitamins • Destruction of nutrients • Preparation • Cooking • Storage • Fortification • Nutrients added during processing • Enrichment • Fortification of a select group of foods with specified levels of B vitamins Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6

B Vitamins • Thiamin • • Roles Dietary sources Sensitive to heat Bioavailability - Compounds in some foods - Sulfites - Vitamin C Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7

FIGURE 7. 1 Thiamin Content of Selected Foods Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8

B Vitamins • Thiamin • Coenzyme - ATP production - DNA and RNA synthesis - Triglyceride synthesis • Deficiency—beri - Four types • Recommended intake - RDA; no UL Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9

B Vitamins • Riboflavin (vitamin B 2) • • • Roles Yellow color Dietary sources Heat and light Bioavailability - Animal-based versus plant-based foods Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10

B Vitamins • Riboflavin (vitamin B 2) • Reduction-oxidation (redox) reactions - Synthesis of bodily substances • Conversion of vitamin A and folate • Synthesis of niacin • Form vitamins B 6 and K • Metabolism of neurotransmitters • Protect biological membranes Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11

B Vitamins • Riboflavin (vitamin B 2) • Deficiency - Ariboflavinosis ▸ Cheilosis ▸ Stomatitis ▸ Glossitis • Recommended intake Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12

B Vitamins • Niacin (vitamin B 3) • Roles • Dietary sources • Synthesized in body - Tryptophan • Measurement - Niacin equivalent (NE) • Bioavailability - Animal-based versus plant-based products Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13

B Vitamins • Niacin (vitamin B 3) • Redox reactions - Coenzyme in ATP production • Synthesis - Fatty acids, cholesterol, steroid hormones, and DNA • Metabolism - Vitamin C and folate • Other roles Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14

FIGURE 7. 4 Increasing Niacin Bioavailability with Lime Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15

B Vitamins • Niacin • Deficiency - Pellagra ▸ Four Ds • Recommended intakes - Supplements - Fortified foods Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16

B Vitamins • Pantothenic acid (vitamin B 5) Contains nitrogen Roles Found almost everywhere Dietary sources Destroyed by high temperatures • Bioavailability - Needs of the body • • • Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17

B Vitamins • Pantothenic acid (vitamin B 5) • Coenzyme - ATP production - Metabolism - Synthesis of important compounds • Deficiency - Burning feet syndrome • Recommended intakes - AI; no UL Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18

B Vitamins • Vitamin B 6 • • Roles Dietary sources Seven known forms Destroyed with extreme or prolonged heat and cold Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19

FIGURE 7. 6 Vitamin B 6 Content of Selected Foods Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 20

B Vitamins • Vitamin B 6 • Coenzyme—pyridoxal phosphate form - Synthesis of nonessential amino acids • Production of nonprotein substances • Deficiency - Microcytic, hypochromic anemia - Similar to riboflavin deficiency • Toxicity • Recommended intakes Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 21

B Vitamins • Biotin (vitamin B 7) • • Roles Dietary sources Bacteria in large intestine Bioavailability - Egg white injury - Alcohol Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22

B Vitamins • Biotin (vitamin B 7) • Component of coenzymes - Energy metabolism pathways • Other roles • Deficiency - Signs and symptoms • Recommended intake - AI; no UL Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23

B Vitamins • Folate (vitamin B 9) • Group of related vitamins • Roles • Dietary sources - Folic acid • Destroyed by excessive cooking • Bioavailability - Supplements and fortified foods • Dietary folate equivalents (DFE) Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24

FIGURE 7. 9 The Role of Folate and Vitamin B 12 in the Conversion of Homocysteine to Methionine Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25

B Vitamins • Folate (vitamin B 9) • Single-carbon transfers - Tetrahydrofolate (THF) - Synthesis of organic compounds - Amino-acid metabolism - Formation of DNA and RNA • Pregnancy - Neural tube defects ▸ Spina bifida Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26

FIGURE 7. 10 Spina Bifida Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 27

B Vitamins • Folate (vitamin B 9) • Deficiency - Megaloblastic, macrocytic anemia • Recommended intake Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 28

B Vitamins • Vitamin B 12 (cobalamin) • Roles • Contains trace element—cobalt - Several nitrogen groups • Only synthesized by bacteria and fungi • Dietary sources Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 29

B Vitamins • Vitamin B 12 (cobalamin) • Coenzyme - ATP production and amino acid metabolism • Deficiency - Secondary ▸ Intrinsic factor (IF) ▸ Pernicious anemia - Folate deficiency • Recommended intakes Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 30

Vitamin C • • • Ascorbic acid Antioxidant functions Dietary sources Bioavailability Destroyed by heat and oxygen Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 31

FIGURE 7. 12 Vitamin C Content of Selected Foods Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 32

Vitamin C • Potent antioxidant • Donates hydrogen ions to other compounds - Inhibits oxidation • Free radical damage - Leads to disease • Nutrient absorption • Bioavailability of certain minerals • Immune system Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 33

Vitamin C • Deficiency • Scurvy - Characteristics • Recommended intakes • RDA - Smokers • UL Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 34

Fat-Soluble Vitamins • Absorbed mostly in small intestine • Dietary lipids and bile • Circulated by chylomicrons in lymph • Eventually circulate to blood - Lipoproteins - Transport proteins • The body stores fat-soluble vitamins • Toxicity Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 35

Vitamin A and the Carotenoids • Three retinoid forms • Retinol - Most biologically active • Retinoic acid • Retinal • Carotenoids • Nonprovitamin and provitamin A carotenoids • Retinol activity equivalent (RAE) Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 36

FIGURE 7. 13 Vitamin A Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 37

Vitamin A and the Carotenoids • Dietary sources • Animal-based foods - Preformed vitamin A • Plant-based foods - Provitamin A carotenoids Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 38

Vitamin A and the Carotenoids • Vision • Retina - Cones ▸ Color - Rods ▸ Black and white ▸ Rhodopsin ▸ Opsin • Cornea Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 39

FIGURE 7. 15 Vitamin A and Vision Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 40

Vitamin A and the Carotenoids • Cell differentiation • Nonspecialized, immature cells become specialized and mature • Reproduction • Immunological functions • Bone health • Preformed vitamin A Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 41

Vitamin A and the Carotenoids • Nonprovitamin A carotenoids • Reduced disease risk - Antioxidant function • Macular degeneration • Vitamin A deficiency disorder (VADD) - Night blindness - Xerophthalmia - Hyperkeratosis Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 42

FIGURE 7. 16 Vitamin A Deficiency Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 43

Vitamin A and the Carotenoids • Toxicity • Preformed vitamin A - Hypervitaminosis A ▸ Characteristics - Birth defects • Carotenoid supplementation - Lung cancer - Hypercarotenodermia Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 44

Vitamin A and the Carotenoids • Recommended intakes • RDA for vitamin A - Preformed vitamin A - Provitamin A carotenoids • UL Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 45

Vitamin D • Nutrient and prohormone • Two forms • Ergocalciferol (vitamin D 2) - Plant-based foods • Cholecalciferol (vitamin D 3) - Animal-based foods - Synthesized in the body • Dietary sources Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 46

Vitamin D • Not easily destroyed • Can by synthesized through exposure to sunlight • Two steps - Cholesterol derivative converted to previtamin D 3 - Converted in skin to vitamin D 3 • Factors influencing ability produce vitamin D 3 Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 47

FIGURE 7. 18 Synthesis of Cholecalciferol (Vitamin D 3) in the Skin Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 48

Vitamin D • Vitamin D 3 metabolism • Step 1 - Vitamin D 3 is converted to 25 hydroxyvitamin D ▸ Liver • Step 2 - 25 -hydroxyvitamin D is converted to 1, 25 -dihydroxyvitamin D (calcitriol) ▸ Kidneys Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 49

FIGURE 7. 19 Activation of Vitamin D Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 50

Vitamin D • Roles • Regulation of blood calcium levels - Parathyroid hormone (PTH) • Blood pressure regulation • Muscle contraction • Nerve function • Other roles Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 51

FIGURE 7. 20 Regulation of Calcium Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 52

Vitamin D • Deficiency • Rickets - Children and infants - Improper bone mineralization - Characteristics • Osteomalacia - Adults - Symptoms • Osteoporosis Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 53

Vitamin D • Recommended intake • RDA - Adults - Elderly • Toxicity - Uncommon - Consequences • UL - Supplemental form Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 54

Vitamins E and K • Vitamin E • Eight different compounds - α-tocopherol • Dietary sources • Easily destroyed • Roles - Antioxidant ▶ Protection of biological membranes ▶ Cancer Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 55

Vitamins E and K • Vitamin E • Deficiency - Uncommon - Characteristics • Recommended intakes - RDA - UL ▸ Supplements Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 56

Vitamins E and K • Vitamin K • Three compounds - Phylloquinone - Menadione • Dietary sources • Destroyed by light and/or heat Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 57

Vitamins E and K • Vitamin K • Roles - Coenzyme ▸ Coagulation - Synthesis of protein • Deficiency - Vitamin K deficiency bleeding - Antibiotics • Recommended intakes Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 58

Taking Dietary Supplements • Definition of dietary supplement • Office of Dietary Supplements • • Safety first Chasing the latest headline More may not be better Natural does not always mean safe Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 59

Taking Dietary Supplements • Situations that may call for a dietary supplement • Talk with your health care provider Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 60

Copyright © 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 61