Transcript Vitamins

Williams' Basic Nutrition & Diet
Therapy
14th Edition
Chapter 7
Vitamins
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
1
Lesson 7.1: The Nature of
Vitamins

Vitamins are noncaloric essential nutrients necessary
for many metabolic tasks.
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
2
Dietary Reference Intakes (p. 94)


Recommendations for nutrient intake by
healthy population groups
Based on gender and age

RDA: Recommended Dietary Allowance
 EAR: Estimated Average Requirement
 AI: Adequate Intake
 UL: Tolerable Upper Intake Level
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
3
The Nature of Vitamins (p. 95)

Discovered while searching for cures for
classic diseases

Dr. James Lind and scurvy
• Sailors dying on long voyages without fresh food
• Lemons and limes provided, no one became ill
• British soldiers got the nickname, “limeys”
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
4
The Nature of Vitamins (cont’d)
(p. 95)

Dr. Frederich Hopkins of Cambridge
University




Two groups of rats
Group 1: Fed synthetic mix of protein,
carbohydrate, fat, mineral salts, and water: All rats
died
Group 2: Fed same ration but with purified milk: All
rats grew normally
Proved that accessory factors are present in
natural foods that are essential to life
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
5
The Nature of Vitamins (cont’d)
(p. 95)


Most vitamins were discovered in the first half
of the 1900s
At first, scientists assigned letters of the
alphabet to each vitamin


A, C, D, E, K
This practice was abandoned in favor of more
specific names based on structure and
function

Cobalamin, pyridoxine, choline
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
6
Definition of Vitamins (p. 95)


It must be a vital, organic substance that is only
necessary in extremely small amounts
It cannot be manufactured by the body in sufficient
quantities to sustain life, so it must be supplied by
diet
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
7
General Functions of Vitamins
(p. 95)





Metabolic tasks
Components of coenzymes
Antioxidants
Components of hormones that affect gene
expression
Component of light-sensitive rhodopsin molecule
(vitamin A)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
8
General Functions of Vitamins
(cont’d) (p. 95)


Metabolism: enzymes and coenzymes
Example: B vitamins are part of coenzymes

Coenzymes needed to perform certain functions,
such as:
 Glucose metabolism
 Protein metabolism
 Fatty acid metabolism
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
9
General Functions of Vitamins
(cont’d) (p. 96)



Tissue structure and protection (e.g., vitamin
C)
Antioxidants to protect cells
Prevention of deficiency diseases

Example: vitamin C prevents scurvy
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
10
Vitamin Metabolism (p. 96)

Fat soluble




Vitamins incorporated with absorbed fat and
transported by chylomicrons
Best absorbed when eaten with fat
May be stored for long periods
Water soluble


Easily absorbed and transported by the portal
circulation
Not stored, so must be eaten on regular basis
(exceptions: B12 and B6)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
11
Lesson 7.2: Fat-Soluble Vitamins


Certain health problems are related to inadequate or
excessive vitamin intake.
Vitamins occur in a wide variety of foods packaged
with the energy-yielding macronutrients
(carbohydrate, fat, and protein).
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
12
Vitamin A (Retinol) (p. 97)

Functions




Vision
Tissue strength and immunity
Growth
Requirements


Food forms and units of measure
Body storage
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
13
Vitamin A Food Forms (p. 98)

Food forms and units of measure


Preformed vitamin A: animal sources
Provitamin A: yellow, orange, or deep green fruits
or vegetables
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
14
Vitamin A Deficiency and Toxicity
(p. 98)

Deficiency disease



Xerosis
Xerophthalmia
Toxicity symptoms

Hypervitaminosis A
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
15
Vitamin A Food Sources (p. 98)

Food sources



Preformed vitamin A: Fish liver oils, liver, egg yolk,
butter, cream, milk fat
Beta-carotene: dark green leafy vegetables, dark
orange vegetables and fruits
Stability: quick cooking with little water to
preserve
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
16
Vitamin D (Calciferol) (p. 99)

Functions



Absorption of calcium and phosphorus
Bone mineralization
Requirements
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
17
Vitamin D Deficiency and Toxicity
(p. 101)

Deficiency disease



Rickets
Osteoporosis
Toxicity syndromes

Infants and children susceptible
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
18
Vitamin D (Calciferol) (cont’d)
(p. 101)


Few good natural sources other than fatty fish
Large portion of intake must come from fortified foods
(e.g., milk)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
19
Vitamin E (Tocopherol) (p. 102)

Functions



Antioxidant to protect cell membranes
Works with glutathione peroxidase as antioxidant
Requirements

RDA for 14 and older is 15 mg/day
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
20
Vitamin E Deficiency and Toxicity
(p. 102)

Deficiency disease



Hemolytic anemia in young infants
Dietary deficiency is rare
Toxicity syndromes

Excessive supplements can interfere with vitamin
K activity
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
21
Vitamin E Food Sources (p. 103)

Food sources



Best: vegetable oils
Nuts, fortified cereal, avocado
Stability

Unstable to heat and alkalis
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
22
Vitamin K (p. 103)


Identified by Henrik Dam in 1929
Functions



Blood clotting: essential component of four clotting factors
Bone development: five proteins in bone and cartilage
require vitamin K–dependent modifications
Requirements



Intestinal bacteria synthesize a constant supply
Insufficient evidence to establish RDA
AI is 120 mcg/day for men and 90 mcg/day for women
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
23
Vitamin K Deficiency and Toxicity
(p. 105)

Deficiency disease: blood loss





Uncommon
Patients with a malabsorption syndrome
Patients treated with antibiotic that kills intestinal
bacteria
Routinely given to infants at birth because
deficient at gestation
Toxicity symptoms

None observed
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
24
Vitamin K Food Sources (p. 105)

Food sources



Green, leafy vegetables
Small amounts of phylloquinone from dairy
products, meats, fortified cereals, fruits,
vegetables
Stability



Fairly stable
Sensitive to light and irradiation
Stored in dark bottles
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
25
Case Study

Mr. Jones is a 69-year-old male who takes an
anticoagulant daily. He has been consuming a vegan
diet by choice for the past 2 years.
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
26
Case Study (cont’d)


Discuss the effect of anticoagulant medications on
overall blood clotting and any vitamins involved in this
process.
What nutritional advice should be given to Mr. Jones
while on anticoagulant medication?
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
27
Lesson 7.3: Water-Soluble
Vitamins and Supplements




Certain health problems are related to inadequate or
excessive vitamin intake.
Vitamins occur in a wide variety of foods packaged
with the energy-yielding macronutrients
(carbohydrate, fat, and protein).
The body uses vitamins to make coenzymes required
for some enzymes to function.
The need for particular vitamin supplements depends
on a person’s vitamin status.
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
28
Vitamin C (Ascorbic Acid)
(p. 105)

Many functions




Connective tissue: helps build strong tissues
through collagen synthesis
General body metabolism: used by adrenals,
brain, kidney, liver, pancreas, thymus, spleen
Antioxidant: similar to vitamin E
Requirements

75 mg/day for women, 90 mg/day for men;
increases for pregnant, lactating women, smokers
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
29
Vitamin C Deficiency and Toxicity
(p. 107)

Deficiency disease




Tissue bleeding
Bone fracture
Scurvy
Toxicity symptoms



Kidney stone formation
GI disturbances
Osmotic diarrhea
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
30
Vitamin C Food Sources (p. 107)

Food sources


Citrus fruits
Stability

Quickly oxidized upon exposure to air and heat
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
31
Thiamin (Vitamin B1) (p. 107)

Functions





Requirements: 1.2 mg/day for men, 1.1 for women
Deficiency disease




Gastrointestinal system
Nervous system
Cardiovascular system
Poor appetite, indigestion, constipation, Beriberi
Toxicity symptoms: no evidence of toxicity
Food sources: especially enriched grains
Stability: fairly stable
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
32
Riboflavin (Vitamin B2) (p. 109)

Functions


Requirements



Macronutrient metabolism to product ATP
Related to total energy requirements
RDA for adults: 1.3 and 1.1 mg/day for men and
women, respectively
Deficiency disease

Areas of the body with rapid cell regeneration
(lips, mouth, tongue)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
33
Riboflavin (Vitamin B2) (cont’d)
(p. 110)

Toxicity symptoms


Food sources



None reported
Most important is milk
Enriched grains and animal protein
Stability

Destroyed by light
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
34
Niacin (Vitamin B3) (p. 110)

Functions



Requirements



Energy metabolism
DNA repair
Depends of many factors
16 niacin equivalents/day for men, 14 for women
Deficiency disease


Weakness, poor appetite, systemic symptoms
Pellagra
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
35
Niacin (Vitamin B3) (cont’d)
(p. 111)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
36
Niacin (Vitamin B3) (cont’d)
(p. 111)

Toxicity symptoms



Food sources



From supplements
Skin flushing
Meat, poultry, fish, legumes
Enriched grain products
Stability

Lost in cooking water unless water is consumed
(soup)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
37
Vitamin B6 (Pyridoxine) (p. 111)

Functions



Requirements



Protein metabolism
Neurotransmitter
Vary with protein intake
1.3 mg/day for men and women up to age 50
Deficiency disease

Deficiency unlikely
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
38
Vitamin B6 (Pyridoxine) (cont’d)
(p. 112)

Toxicity symptoms



Food sources


From supplements
Uncoordinated movement and nerve damage
Widespread in foods
Stability

Stable to heat but sensitive to light and alkalis
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
39
Folate (p. 112)

Functions



Requirements


DNA synthesis
Regulation of blood homocysteine levels
400 mcg/day
Deficiency diseases:


Megaloblastic anemia
Neural tube defects
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
40
Folate (cont’d) (p. 114)

Toxicity symptoms


Food sources


None from intake of food
Widely distributed in foods, both naturally
occurring and fortified
Stability

Easily destroyed by heat and leaches into cooking
water
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
41
Cobalamin (Vitamin B12) (p. 115)

Functions




Requirements


Regulation of blood homocysteine levels
Heme synthesis
DNA synthesis and cell division
Small amount usually met by diet
Deficiency disease


Nonspecific symptoms
Pernicious anemia
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
42
Case Study (cont’d)


Is B12 deficiency a concern for Mr. Jones? Why or
why not?
List three nutritional recommendations for Mr. Jones.
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
43
Cobalamin (Vitamin B12) (cont’d)
(p. 115)
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
44
Cobalamin (Vitamin B12) (cont’d)
(p. 116)

Toxicity symptoms


Food sources


None found
Bound to protein in foods
Stability

Stable in ordinary cooking
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
45
Pantothenic Acid (p. 116)

Functions



Requirements





Cellular metabolism
Protein acetylation and protein acylation
No specific RDA
Deficiency disease: unlikely
Toxicity symptoms: none observed
Food sources: occurs widely in food
Stability: stable to acid and heat but sensitive to
alkalis
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
46
Biotin (p. 117)

Functions






Coenzyme for carboxylases
Requirements: extremely small, 30 mcg/day
Deficiency disease: no natural deficiency
known
Toxicity symptoms: none known
Food sources: widely distributed in natural
foods
Stability: stable but water-soluble
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
47
Choline (p. 118)


Data insufficient to determine its essentiality
Functions



Structural integrity of cell membranes
Neurotransmission
Requirements: 550 mg/day for men, 425
mg/day for women
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
48
Choline (cont’d) (p. 118)




Deficiency disease: liver and muscle damage
Toxicity symptoms: lowered blood pressure, fishy
body odor
Food sources: occurs in a wide variety of foods
Stability: relatively stable nutrient and water-soluble
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
49
Phytochemicals (p. 118)



Bioactive molecules with health benefits
Nonessential
People eating whole fruits and vegetables benefitted
more than those who did not
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
50
Phytochemical Functions (p. 120)

Function: wide variety




Antioxidant function
Hormonal actions
Interactions with enzymes and DNA replication
Antibacterial effects
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
51
Phytochemical Intake (p. 120)

Recommended intake



No established DRIs
Consume a colorful variety of fruits, vegetables,
whole grains, nuts
Food sources

Seven color categories
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
52
Vitamin Supplementation (p. 120)




Definition
Use is common in United States
Only 3% to 4% of Americans eat according to
guidelines
Recommendations for nutrient
supplementation

Life cycle needs
 Pregnancy and lactation
 Infants, children, adolescents
 Older adults
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
53
Case Study (cont’d)


Mr. Jones decides he would like to add supplements
to ensure he is obtaining all essential nutrients. He
has tripled his vitamin C intake along with extra
doses of vitamin A and several of the B vitamins.
What guidance should be given to Mr. Jones?
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
54
Vitamin Supplementation (cont’d)
(p. 121)

Lifestyle




Restricted diets: those following fad diets, vegans
Smoking: reduces vitamin C pool
Alcohol: can reduce absorption of B-complex
vitamins
Disease: requires nutrition assessment
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
55
Megadoses (p. 122)

Use of vitamins to:




Alleviate illness
Prevent disease
Relieve symptoms
Potential toxicity
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
56
Supplementation Principles
(p. 122)






Read labels carefully
Vitamins can be harmful in large amounts
Professional should determine individual’s need
All nutrients work together to promote good health
Food is the best source of nutrients
Evaluate the information
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
57
Functional Foods (p. 124)




No legal definition
Food that provides a health benefit beyond its basic
nutritional value
American Dietetic Association recognizes possible
benefit
Recommendations for intake not established
Copyright © 2013 Mosby, Inc., an imprint of Elsevier Inc. All rights reserved.
58