Transcript Fat Soluble Vitamins 2010

The Vitamins
Fat Soluble Vitamins
Water Soluble Vitamins
Objectives
Characteristics of Vitamins
Vitamins are micronutrients
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Vitamins are essential.
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Very small amounts are needed by the body (>1 gm)
Very small amounts are contained in foods.
The roles they play in the body are very important.
Most vitamins are obtained from the foods we eat.
Some are made by bacteria in the intestine
One is made in the skin
There is no perfect food that contains all the
vitamins in the right amount.
Objectives
Characteristics of Vitamins
Vitamins are non-energy producing
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They do not contain kcalories.
They are involved in extracting energy
from the macronutrients.
Some vitamins in foods are
precursors.
Vitamins are classified according
to how soluble they are in fat or
water.
Fat Soluble Vitamins vs.
Water Soluble Vitamins
Variety is the Key
Fat Soluble Vitamins
Vitamin A, D, E, K
Objectives
Objectives
After reading Chapter 6, completing a concept
map and class discussion, you will be able to:
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Identify fat soluble vitamins
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Distinguish fat soluble vs water soluble
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Identify food sources for Vitamins A,D,E,K
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Identify toxicity levels for Vitamins A,D,E,K
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Describe one major role for Vitamins A,D,E,K
Fat Soluble Vitamins:
Characteristics
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Essential
Organic Structure
Non-energy Producing
Micronutrients
Stability
Bioavailability
Toxicity
Vitamin Misconception
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“More is Better”?
Toxicity
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Toxicity is rare but it is a possibility.
Toxicity is very rarely associated with
food.
Toxicity results from overuse of
supplements.
Vitamin Concept Map
FUNCTIONS
Food Sources
Vitamin
Other Facts
Vitamin A
Functions
SOURCES
Vitamin A
Other Facts
Vitamin A
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Other names
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Preformed Vitamin A – retinyl esters
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Retinol, Retinal, Retinoic acid
Sources: animal foods, fortified foods,
pharmaceutical supplements
Provitamin A - Precursors=carotenoids
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Beta-carotene and other carotenoids
Sources: plant foods
Vitamin A
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2001 RDA
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Men: 900 g RAE/day
Women: 700 g RAE/day
RAE=Retinol Activity Equivalents
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1 microgram of retinol
12 micrograms of beta-carotene
24 micrograms of other precursor carotenoid
Upper level for adults: 3000 g/day
Vitamin A
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Chief functions in the body
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Vision
Maintenance of cornea, epithelial cells,
mucous membranes, skin
Bone and tooth growth
Reproduction
Immunity
Antioxidant effect of beta-carotene
Vitamin A in Vision
Vitamin A
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Function in protein synthesis and
cell differentiation
Vitamin A Deficiency
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Night blindness
Xerosis (corneal drying)
Bitot’s spots
Karatomalacia
Xerophtalmia
Hyperkaratosis
Impaired immunity
Vitamin A Deficiency
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Keratinization
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Vitamin A
deficiency
symptom
Vitamin A Toxicity
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Toxicity from provitamin A impossible
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Conversion of carotenoids to retinal highly
regulated by the body
Homeostatic mechanisms control tightly
Toxicity from preformed A inevitable
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Efficient absorption and hepatic storage of A
Storage continues until pathologic condition
develops; liver stores ~80% of body reserves
Vitamin A Toxicity
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Large % of population in developed
nations have intakes of preformed
vitamin A higher than the RDA
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75% of people may be routinely ingesting
more than RDA
Some studies suggest that as little as
twice the RDA intake may contribute to
subclinical Vitamin A toxicity
Acute Toxicity
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Occurs when adults ingest >100x RDA of
preformed Vitamin A for a period of hours
or several days.
Occurs when children ingest >20x RDA
of preformed Vitamin A for same period.
Less of a problem than chronic toxicity
Acute Toxicity
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Acute toxicity symptoms
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Blurred vision
Nausea, vomiting, vertigo
Increase of pressure inside skull,
mimicking brain tumor
Headaches
Chronic Toxicity
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Occurs when adults ingest
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>25,000 IU preformed Vitamin A for >6 years
>100,000 IU preformed A for >6 months
Wide individual variabilty
Children particularly sensitive to daily
intakes of 1500 IU/kg body weight.
Elderly at significantly greater risk
Chronic Toxicity
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Chronic toxicity symptoms
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Increased activity of osteoclasts
causing reduced bone density
Liver abnormalities
Birth defects
Vitamin A & Macular Degeneration
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Studies in the elderly suggest that the use of
large doses of certain vitamins and minerals are
beneficial in the prevention of macular
degeneration
Some evidence exists that improvement in
existing damage may be seen
Vitamin A & Macular Degeneration
Vitamin/
Mineral
A
Amount
% DV
14,320 IU
286
C
235 mg
371
E
200 IU
667
Zinc
348 mg
232
Copper
0.8 mg
40
WARNING
Vitamin A & Macular Degeneration
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Vitamin A directs the process of borrowing and
redepositing calcium in the bone
Too much preformed Vitamin A (retinol) can
promote fractures.
Use Vitamin A in form of beta-carotene, a precurser form which does not increase fractures
Vitamin A Sources
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Beta-carotene
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Dark leafy green
vegetables, spinach,
broccoli
Deep orange veggies
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Carrots, pumpkin,
squash, sweet potato
Deep orange fruits
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Apricots, cantaloupe
Vitamin A Sources
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Retinol
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Fortified milk, butter
cheese, cream
Fortified margarine
Eggs
Liver
Copyright 2005 Wadsworth Group, a division of Thomson Learning
Vitamin D
Functions
SOURCES
Vitamin D
Other Facts
Vitamin D
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Other names
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Calciferol
1,25-dihyroxy vitamin D (calcitriol)
Animal version: vitamin D3 or
cholecalciferol
Plant version: vitamin D2 or
ergocalciferol
Precursor is the body’s own cholesterol
Vitamin D
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1997 adequate intake (AI)
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19-50 years: 5 g/day
51-70 years: 10 g/day
more than 70 years: 15 g/day
Upper level for adults: 50 g/day
Vitamin D
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Chief functions in the body
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Mineralization of bones
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raises blood calcium and phosphorus by
increasing absorption from digestive tract
withdrawing calcium from bones
stimulating retention by kidneys)
Vitamin D
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Calcium and phosphorous absorption
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Without D only 10-15% dietary calcium
absorbed
With D absorption increased to 30-40%
Without D about 60% phosphorous
absorbed
With D absorption increased to ~80%
Vitamin D
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Recent research indicates Vitamin D has
a role in the prevention of
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Heart disease
Type-1 Diabetes
Multiple Sclerosis
Rheumatoid Arthritis
Crohn’s Disease
Certain Cancers
Vitamin D
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Nonskeletal functions of Vitamin D
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Brain, prostate, breast, colon tissues and
immune cells have Vitamin D receptors and
respond to 1,25-dihydroxyvitamin D (the
active form of D)
1,25-dihydroxyvitamin D controls more than
200 genes
Potent immunomodulator
Vitamin D
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Deficiency
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Rickets
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Inadequate calcification
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Misshapen, deformed
Lax muscles with spasm
Osteomalacia
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Loss of calcium
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Soft, deformed bones
Pain, weakness
Vitamin D
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Toxicity – Hypervitaminosis D
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Elevated blood calcium
Calcification of soft tissues (blood
vessels, kidneys, heart, lungs, tissues
around joints)
Thought to be the most frequently
occurring vitamin toxicity but………..
Vitamin D
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The Sunshine Vitamin
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Approximately 90% of
Vitamin D requirement
obtained from sun
UV light from sun hits
skin, triggers synthesis
Activated in liver and
kidneys
Vitamin D Sources
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Fortified
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Milk
Margarine
Butter
Cereal
Veal, Beef
Egg yolk
Fatty fish (salmon, sardines, herring)
Vitamin E
Functions
SOURCES
Vitamin E
Other Facts
Vitamin E
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Other name: alpha-tocopherol
2000 RDA
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Adults: 15 mg/day
Upper level for adults: 1000 mg/day
Easily destroyed by heat and oxygen
Vitamin E
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Chief function in the body
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Antioxidant
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stabilization of cell membranes,
regulation of oxidation reactions,
protection of polyunsaturated fatty acids
and vitamin A
Vitamin E: Antioxidant
Vitamin E Sources
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Polyunsaturated plant oils
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Margarine
Salad dressing
Leafy green vegetables
Wheat germ
Whole grains
Egg yolks
Nuts and seeds
Vitamin K
Functions
SOURCES
Vitamin K
Other Facts
Vitamin K
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Other names
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Phylloquinone
Manaquinone
Menadione
Naphthoquinone
2001 AI
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Men: 120 g/day
Women: 90 g/day
Vitamin K
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Family of vitamins
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Naturally found in primarily two forms
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Identified by German scientists
Required for normal blood clotting
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K1 and K2
K3 simpler form; synthetically created
Named “K” for German word for “clot”
No Tolerable Upper Limit
Vitamin K
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Bacteria in intestines produce ~75%
of Vitamin K absorbed by body daily
Vitamin K not stored in body
Vitamin K needs to be supplied daily
Absorption dependent on healthy
liver and gall bladder
Vitamin K
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K1 produced by plants we eat
K2 produced by bacteria in intestine;
converted from K1
K2 more potent (15x); more active; and
wider range of activities
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Better absorbed; longer biological activity
Predominant form found in body tissues
Used preferentially by all tissues but liver
Vitamin K
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Chief functions in the body
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Synthesis of blood-clotting proteins and
bone proteins that regulate blood
calcium
Vitamin K: Other Functions
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Synthesis of bone proteins that
regulate blood calcium; prevent bone
loss
Integration of calcium into bones
Prevent calcium deposition in blood
vessels (vascular calcification)
Maintain blood vessel elasticity
Vitamin K and Medication
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Bisphosponates – osteoporosis drugs
 K improves utilization of these drugs
Wafarin - anticoagulants
 As little as 1 mg/day can interfere with
anticoagulant activity of drug
Vitamin K Sources
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Bacterial synthesis
in GI tract
Leafy green
vegetables
Cruciferous
vegetables
Liver
Milk
Vitamin K Sources
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Vitamin K1 produced by plants and algae
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Broccoli, kale, chard; plant oils like canola
and soybean
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Hydrogenated soybean oil has ineffective K
Vitamin K2 produced by bacteria in gut
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Food Sources: fermented soybean (Natto);
dairy products, egg yolk
Objectives
Antioxidants
Objectives
Antioxidants
Objectives
Objectives
After reading Chapter 6, completing a concept
map and class discussion, you will be able to:

Identify fat soluble vitamins

Distinguish fat soluble vs water soluble

Identify food sources for Vitamins A,D,E,K

Identify toxicity levels for Vitamins A,D,E,K
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Describe one major role for Vitamins A,D,E,K
Objectives
Fat Soluble
Vitamins