Transcript Fat-Soluble Vitamins

Fat Soluble Vitamins
Water Soluble Vitamins
THE VITAMINS
Prepared by:
Mona Abo Hasera
CHARACTERISTICS OF VITAMINS
Vitamins are micronutrients
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Vitamins are essential.
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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
There is no perfect food that contains all the
vitamins in the right amount.
Vitamins are non-energy producing
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Very small amounts are needed by the body (>1 gm)
Very small amounts are contained in foods.
They do not contain kcalories.
Vitamins are classified according to how soluble they
are in fat or water.
FAT SOLUBLE VITAMINS VS.
WATER SOLUBLE VITAMINS
A, D, E, K
FAT-SOLUBLE VITAMINS
FAT-SOLUBLE VITAMINS
found in fats and oils
 require bile for absorption
 enter the lymph, then the blood
 held and stored in fatty tissues
 Needed in small amounts
 may reach toxic levels
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 not
readily excreted
VITAMIN A
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3 forms in the body
 retinol
 retinal
 retinoic acid
collectively known as retinoids
Retinol, the alcohol form
Retinal, the aldehyde form
Retinoic acid, the acid form
Cleavage at this point can
yield two molecules of vitamin A*
Beta-carotene, a precursor
VITAMIN A
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precursor: betacarotene
 derived
from plant foods
 can split and form
retinol in intestine and
liver
VITAMIN A FUNCTION
vision
 maintain epithelial tissue and skin
 support reproduction and growth
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Immune system
Bone development
VITAMIN A
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deficiency
 infectious
disease
 pneumonia,
measles, diarrhea
 keratinization
 dry,
 night
rough, scaly skin
blindness
Vitamin A Sources
Beta-carotene
Dark leafy green
vegetables, spinach,
broccoli
Deep orange veggies
Carrots, pumpkin,
squash, sweet potato
Deep orange fruits
Apricots, cantaloupe
Retinol
Fortified milk, butter
cheese, cream
Fortified margarine
Eggs
Liver
VITAMIN D
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body can make
 from
sunlight
 precursor made from
cholesterol
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production occurs in liver and kidney
 diseases
can affect activation
VITAMIN D FUNCTION
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part of the bone-making/maintenance team
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maintains blood concentrations of Ca & P
Mineralization of bones
 raises blood calcium and phosphorus by increasing absorption
from digestive tract
 withdrawing calcium from bones
 stimulating retention by kidneys
deficiencies
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ultimately creates a calcium deficiency
rickets, osteomalacia
VITAMIN D
sources
 fortified
food: milk, margarine, cereals, beef,
eggs
 sun
 storage from the summer does not last the
winter
VITAMIN E
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antioxidant
 defender
against free radicals
 polyunsaturated
fatty acids
may reduce the risk of heart disease
 deficiencies
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 rare
 erythrocyte
hemolysis
VITAMIN E
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widespread in food
 easily
destroyed by heat processing
VITAMIN K
aids in blood clotting and
bone mineralization
 deficiency causes hemorrhagic disease
 sources
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 made
by bacteria in GI tract
absorbed and stored in liver
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liver is also high in vitamin K
Table 10-1, p. 326
B complex , c
WATER-SOLUBLE VITAMINS
WATER SOLUBLE VITAMINS
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The B-complex vitamins are often associated with giving
a person more energy. This is due to the fact that these
vitamins each play different roles with energy
metabolism in the body. When they are present in the
body, they allow energy to be used more readily by the
body.
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Since these vitamins are water soluble, they are not
stored in the body like fat soluble vitamins. They
dissolve in water and are excreted from the body in
urine. Therefore, it is important to consume foods rich in
these vitamins each day in order to fulfill the body’s
need.
B COMPLEX VITAMINS
Co-enzymes (activate enzymes)
 Found in the same foods
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 Single
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deficiency rare
Act together in metabolism
 Metabolic
and fat
pathways used by protein, carbohydrate,
B COMPLEX VITAMINS
Thiamin (B1)
 Riboflavin (B2)
 Niacin (B3)
 Pantothenic Acid
 Biotin
 Pyridoxine (B6)
 Folate
 Vitamin B-12
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B COMPLEX PRIMARY FUNCTIONS
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Energy metabolism
 Thiamin
(B-1), Riboflavin (B-2), Niacin (B-3),
Pyridoxine (B-6), Biotin, Pantothenic Acid
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Red blood cell synthesis
 Folate,
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B12
Homocysteine metabolism
 Folate,
B12, B6
VITAMIN C
Synthesized by most animals (not by humans)
 Decrease absorption with high intakes
 Excess excreted
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FUNCTIONS OF VITAMIN C
 Reducing
agent (antioxidant)
 Iron absorption (enhances)
 Synthesis of collagen
 Immune functions
 Does
not prevent colds, but may reduce
duration of symptoms by a day
 Wound
healing
VITAMIN C DEFICIENCY: HISTORY OF
SCURVY
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Vitamin C (ascorbic acid) deficiency leads to scurvy,
a disease characterized by weakness, small
hemorrhages throughout the body that cause gums
and skin to bleed, and loosening of the teeth.
Sailors that were out at sea for months on end
would often develop scurvy unless the captain had
the foresight to pack limes and other citrus fruits.
DEFICIENCY OF VITAMIN C
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Scurvy
 Deficient
diet for 20-40 days
 Fatigue, pinpoint hemorrhages
 Bleeding gums and joints. Hemorrhages
 Associated with poverty; macrobiotic diet
SCURVY
Scorbutic Rosary
Follicular
Hemorrhages
FOOD SOURCES OF VITAMIN C
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Citrus fruit
Potato
Green pepper
Cauliflower
Broccoli
Strawberry
Romaine lettuce
Spinach
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Easily lost through
cooking
Sensitive to heat
Sensitive to iron,
copper, oxygen
VITAMIN C EXCESS
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Hemochromatosis
 Vitamin
C enhances iron absorption
Oxalate kidney stones
 Erodes tooth enamel
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VITAMIN C DEFICIENCY
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In the U.S., deficiency is seen mostly in
alcoholic persons with poor diets and older
persons who eat poorly (no fresh fruits and
vegetables)
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EXPERIMENT
Principle
1. KIO3 is used as a titrant and it is added to an ascorbic acid
solution that contains a strong acid and potassium iodide (KI).
2. KIO3 reacts with KI, liberating molecular iodine (I2):
KIO3 + 5KI + 6H+ → 3I2 + 6K+ + 3H2O
C6H8O6 + I2 → C6H6O6 + 2I- + 2H+
(1)
(2)
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PROCEDURE
1. Pipette 25 ml of the provided ascorbic acid solution into a 250 ml conical
flask,
2. Add  4 ml of 2M HCl,
3. Add  5 ml of potassium iodide (KI) solution and 3 ml starch solution.
4. Then titrate with the standard potassium iodate (KIO3) solution until
the solution turns intense blue. Write down the standard potassium
iodate (KIO3) solution volume.
5. Pipette 25 ml of an unknown ascorbic acid sample, a kind of juice, into a
250 ml conical flask, then follow the same procedure of steps 1-4 and
write down the volume of the standard KIO3 solution determine the
concentration (mol/ml) of ascorbic acid in the selected sample.
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PROCEDURE