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Chapter 7 The Vitamins. Nutrition: Concepts & Controversies, 12e Sizer/Whitney. Learning Objectives. List the fat-soluble and water-soluble vitamins, and describe how solubility affects the absorption, transport, storage, and excretion of each type. - PowerPoint PPT Presentation
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Chapter 7Chapter 7
The VitaminsThe Vitamins
Nutrition: Concepts & Controversies, 12e Nutrition: Concepts & Controversies, 12e Sizer/WhitneySizer/Whitney
Learning ObjectivesLearning Objectives
List the fat-soluble and water-soluble vitamins, and describe how solubility affects the absorption, transport, storage, and excretion of each type.
Explain how vitamins and minerals work in combination to maintain the health of the bones.
Name some functions of vitamin D not associated with the bones.
Learning ObjectivesLearning Objectives
Define the term antioxidant, and name the vitamins that act as antioxidants in the body.
Discuss the roles of B vitamins in body tissues, and explain in a general way how B vitamins assist with energy metabolism.
Present arguments both for and against vitamin fortification of foods.
Learning ObjectivesLearning Objectives
Suggest foods that can help to ensure adequate vitamin intakes without providing too many calories.
Justify this statement: “It is better to get vitamins from food than from supplements.”
List some valid reasons why supplements may be required by some people.
Definition and Classification of Definition and Classification of VitaminsVitamins
Vitamin Essential, noncaloric, organic
Role of vitamins Vitamin precursors Classes
Absorption Roles
Vitamin NamesVitamin Names
Characteristics of the Fat-Soluble Characteristics of the Fat-Soluble and Water-Soluble Vitaminsand Water-Soluble Vitamins
The Fat-Soluble VitaminsThe Fat-Soluble Vitamins
A, D, E, and K Food sources
Storage Toxicity
Deficiency Roles within the body
Vitamin AVitamin A
Precursor Beta-carotene
Active forms in the body Retinol Retinal Retinoic acid
Food sources
Vitamin A – Roles and DeficiencyVitamin A – Roles and Deficiency
Gene regulation Retinoic acid
Eyesight Process of light perception Maintenance of healthy cornea Rhodopsin molecule
An EyeAn Eye
Vitamin A – Roles and DeficiencyVitamin A – Roles and Deficiency
Night blindness Deficiency
Xerophthalmia and blindness Keratinization
Deficiency
Cell differentiation Immune function Growth
Vitamin A – Deficiency and Vitamin A – Deficiency and ToxicityToxicity
Deficiency Worldwide problem
BlindnessHIV
Toxicity Symptoms food sources
Liver
Vitamin A – Deficiency and Vitamin A – Deficiency and ToxicityToxicity
Toxicity Supplements Higher risk groups
Recommendations DRI recommendation based on body weight
Food sources Animal origin
Liver Plant origin
Vitamin A Deficiency and ToxicityVitamin A Deficiency and Toxicity
Vitamin A – Snapshot Vitamin A – Snapshot
Beta-CaroteneBeta-Carotene
Plant-based foods Colorful groups
Macular degeneration Dietary antioxidant Measuring beta-carotene
Retinol activity equivalents (RAE) Toxicity Food sources
Excess Beta-Carotene Symptom: Excess Beta-Carotene Symptom: Discoloration of the SkinDiscoloration of the Skin
Vitamin DVitamin D
Body can synthesize all it needs Sunlight
Transformation Liver and kidneys
Estimated deficiency prevalence
Vitamin D – Roles Vitamin D – Roles
Bone integrity Hormone Dangers with
deficiency
Vitamin D – Too Little, Too MuchVitamin D – Too Little, Too Much
Deficiency Rickets
Recommendations for prevention Osteomalacia
Recommendations
Toxicity Signs of toxicity
RicketsRickets
Vitamin DVitamin D
Ultraviolet B light rays Cholesterol
Sunbathing risks Sunscreen
Exposure times Intake
recommendations Food sources
Factors Affecting Vitamin D Factors Affecting Vitamin D Synthesis Synthesis
Vitamin D - SnapshotVitamin D - Snapshot
Vitamin EVitamin E
Roles of vitamin E Antioxidant
Deficiency Symptoms
Toxicity Dietary intake vs. supplemental intake
Recommendations Food source
Free-Radical Damage and Free-Radical Damage and Antioxidant ProtectionAntioxidant Protection
Vitamin E – Snapshot Vitamin E – Snapshot
Vitamin KVitamin K
Roles Blood clotting Bone proteins
Deficiency Toxicity
Jaundice Requirements
Sources
Vitamin K – SnapshotVitamin K – Snapshot
The Water-Soluble VitaminsThe Water-Soluble Vitamins
Dissolve in water Absorption Transport Excretion
Sources Food Supplements
Vitamin CVitamin C
Roles Connective tissues
Collagen Antioxidant
Protects ironProoxidant
Deficiency symptoms Scurvy
Scurvy Symptoms – Gums and Scurvy Symptoms – Gums and SkinSkin
Vitamin CVitamin C
Toxicity Safe doses
Recommendations Tobacco use Physical stressors
Food sources Destruction of vitamin
C
Vitamin C – Snapshot Vitamin C – Snapshot
The B Vitamins in UnisonThe B Vitamins in Unison
Function as part of coenzymes Combines with enzyme to activate it Coenzyme shape
Roles in metabolism Help the body use the energy-yielding
nutrients for energy Cell multiplication
Coenzyme ActionCoenzyme Action
Some Roles of the B Vitamins in Some Roles of the B Vitamins in Metabolism: ExamplesMetabolism: Examples
The B Vitamins in UnisonThe B Vitamins in Unison
Deficiencies Every cell is affected Symptoms Rarely are isolated deficiencies
Thiamin Thiamin
Energy metabolism of all cells
Nerve cell membranes Deficiency
Beriberi Alcohol abuse
DRI recommendation Food sources
Thiamin SnapshotThiamin Snapshot
RiboflavinRiboflavin
Role in energy metabolism of all cells Deficiencies
Examples Destruction of vitamin
UV light Irradiation Heat
Riboflavin SnapshotRiboflavin Snapshot
NiacinNiacin
Participates in energy metabolism
Deficiency Pellagra
Toxicity Physician
administration “Niacin flush”
Niacin SnapshotNiacin Snapshot
FolateFolate
Helps synthesize DNA Normal metabolism of several amino acids
Deficiency Causes Outcomes of deficiency
Anemia, diminished Immunity, abnormal digestive function
Cancer risk
Interaction with medications
FolateFolate
Birth defects Neural tube defects (NTD)
Toxicity UL
Recommendations Food sources of folate
Destruction of folate
Incidence of a Common NTD, Incidence of a Common NTD, Spina Bifida, Over TimeSpina Bifida, Over Time
Folate SnapshotFolate Snapshot
Vitamin BVitamin B1212
Closely related to folate Helps maintain sheaths around nerve fibers Deficiency
May be masked by folic acid intake Pernicious anemia
Vitamin B12 absorption Intrinsic factor
Food sources
Vitamin BVitamin B1212 Snapshot Snapshot
Vitamin BVitamin B66
Roles Participates in over 100 reactions Additional roles
Deficiency General symptoms
Toxicity Intake recommendations
Food sources
Vitamin BVitamin B66 Snapshot Snapshot
Biotin and Pantothenic AcidBiotin and Pantothenic Acid
Important for energy metabolism Biotin
Cofactor for enzymes Gene expression No UL
Pantothenic acid Key coenzyme
Non-B VitaminsNon-B Vitamins
Choline Nonvitamins
Carnitine Inositol Lipoic acid
Vitamin Supplements: Do the Vitamin Supplements: Do the Benefits Outweigh the Risks?Benefits Outweigh the Risks?
Controversy 7
Some Valid Reasons for Taking Some Valid Reasons for Taking SupplementsSupplements
Arguments Against Taking Arguments Against Taking SupplementsSupplements
Food rarely causes nutrient imbalances or toxicities
Toxicity Supplement contamination Lift-threatening misinformation Unknown needs False sense of security Whole foods are best
Can Supplements Prevent Heart Can Supplements Prevent Heart Disease or Cancer?Disease or Cancer?
Oxidative stress Vitamin C
Population studies Animal studies Cell studies Intervention studies
Vitamin E Beta-carotene
Supplements Safety and RisksSupplements Safety and Risks
Safety Food and Drug Association (FDA)
Risks Dangers for your body
Selecting a SupplementSelecting a Supplement
Choose type Read labels Target your needs Choosing doses Quality Avoid marketing
traps