Transcript Fat-soluble vitamins

Faculty of Applied Medical Sciences
Department of Nursing
Nutrition (NUTN 204)
VITAMINS
Ahmad Albalawi
Learning Objectives
• Identify the different micronutrients their
sources and recommended intake and their
corresponding toxicities and deficiencies;
• Identify the health effects of the different
micronutrients
Topic Outline
• Facts about vitamins
• Fat-soluble vitamins (ADEK)
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Sources
Functions
Toxicities
Deficiencies
• Water-soluble vitamins (B-complex vit. C, folate)
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Sources
Functions
Toxicities
Deficiencies
FACTS ABOUT VITAMINS
• Vitamins are organic compounds made of
carbon, hydrogen, oxygen, and sometimes
nitrogen or other elements.
• Vitamins facilitate biochemical reactions
within cells to help regulate body processes
such as growth and metabolism.
FACTS ABOUT VITAMINS
• Vitamins are essential to life and
– are individual molecules, not long chains of
molecules linked together.
– do not provide energy but are needed for
metabolism of energy.
– are needed in microgram or milligram
quantities, not gram quantities. because they
are needed in such small amounts, they are
referred to as micronutrients.
FACTS ABOUT VITAMINS
• Vitamins are chemically
defined
– Cannot be distinguished
between natural and artificial
– Synthetic vitamins are easily
absorbed because they are
not bound (free)
FACTS ABOUT VITAMINS
• Vitamins are susceptible to destruction
– Thiamin is heat sensitive
– Riboflavin is resistant to heat, acid, and
oxidation but is quickly destroyed by light
– Baking soda destroys thiamin
– Fifty percent to 90% of folate in foods may be
lost during preparation, processing, and
storage
– Vitamin C is destroyed by heat, air, and alkalis.
FACTS ABOUT VITAMINS
• Vitamins may exist in more than one form
– Forms of vitamin A:
» Retinol (reproduction)
» Retinal (vision)
» Retinoic acid (regulate growth)
• Some vitamins have provitamins
– Beta-carotene is a provitamin of vitamin A
FACTS ABOUT VITAMINS
• Some vitamins are coenzymes
– All B vitamins work as coenzymes to facilitate
thousands of chemical conversions
– Thiamin, riboflavin, niacin, and biotin
participate in enzymatic reactions that extract
energy from glucose, amino acids, and fat
– Folacin facilitates both amino acid metabolism
and nucleic acid synthesis
FACTS ABOUT VITAMINS
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Vitamins are essential
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Body can make vitamins A, D, and niacin if appropriate
precursors are available
Microorganisms in the GIT synthesize vitamin K and
B12
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Some vitamins are antioxidants (substances that
donate electrons to free radicals to prevent
oxidation)
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Some Vitamins are used as food additives
FACTS ABOUT VITAMINS
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Vitamins are used as drugs (megadoses)
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Large doses of niacin are used to lower
cholesterol, LDL-cholesterol, and triglycerides in
people with hyperlipidemia who do not respond to
diet and exercise
Tretinoin (retinoic acid, a form of vitamin A) is
used as a topical treatment for acne vulgaris and
orally for acute promyelocytic leukemia.
Gram quantities of vitamin C promote wound
healing in patients with thermal injuries.
FACTS ABOUT VITAMINS
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Vitamin Classifications Based On Solubility
1. Fat-soluble
» Vitamins A, D, E, and K
2. Water-soluble
» Vitamin C and the B vitamins (thiamin,
riboflavin, niacin, folate, B6, B12, biotin, and
pantothenic acid biotin, and pantothenic acid).
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Solubility determines vitamin absorption,
transportation, storage, and excretion.
Fat-soluble vitamins
VITAMIN A SOURCES
• Retinol: Liver, milk, butter, cheese, cream,
egg yolk, fortified milk, margarine, and
ready-to-eat cereals
• Beta-Carotene: Green leafy vegetables,
broccoli, carrots, peaches, pumpkin, red
peppers, sweet potatoes, winter squash,
mango, watermelon, apricots, cantaloupe
Fat-soluble vitamins
Fat-soluble vitamins
FUNCTIONS OF VITAMIN A
1. The formation of visual purple (adaptation
to dim light)
2. Normal growth and development of bones
and teeth
3. The formation and maintenance of mucosal
epithelium to maintain healthy functioning
of skin and membranes, hair, gums, and
various glands
4. Important role in immune function
Fat-soluble vitamins
DEFICIENCIES IN Vit A
• Night blindness, or the slow
recovery of vision after flashes
of bright light at night
• Bone growth ceases; bone shape
changes; enamel-forming cells in
the teeth malfunction; teeth
crack and tend to decay.
• Skin becomes dry, scaly, rough,
and cracked; keratinization or
hyper-keratosis develops;
mucous membrane cells flatten
and harden: Eyes become dry
(xerosis); irreversible drying and
hardening of the cornea can
result in blindness
Fat-soluble vitamins
DEFICIENCIES IN Vit A
• Decreased saliva secretion → difficulty
chewing, swallowing → anorexia
• Decreased mucous secretion of the stomach
and intestines → impaired digestion and
absorption → diarrhea, increased excretion of
nutrients
• Susceptibility to respiratory, urinary tract, and
vaginal infections increases.
Fat-soluble vitamins
TOXICITIES IN Vit A
• Headaches
• Vomiting
• Double vision
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Hair loss
Bone abnormalities
Liver damage
Birth defects
Fat-soluble vitamins
VITAMIN D SOURCES
• Sunlight on the skin
Liver
fatty fish,
egg yolks, fortified milk,
cereals, and margarine
Fat-soluble vitamins
VITAMIN D FUNCTIONS
1. Maintains serum calcium concentrations by:
a. Stimulating GI absorption
b. Stimulating the release of calcium from the
bones
Fat-soluble vitamins
DEFICIENCIES IN VIT D
• Rickets (in infants and
children)
• Retarded bone growth
• Bone malformations (bowed
legs)
• Enlargement of ends of long
bones (knock-knees)
• Deformities of the ribs
(bowed, with beads or
knobs)
• Delayed closing of the
fontanel → rapid
enlargement of the head
Fat-soluble vitamins
DEFICIENCIES IN VIT D
Fat-soluble vitamins
DEFICIENCIES IN VIT D
• Decreased serum calcium
and/or phosphorus
• Malformed teeth; decayed
teeth
• Protrusion of the abdomen
related to relaxation of the
abdominal muscles
• Increased secretion of
parathyroid hormone
Fat-soluble vitamins
DEFICIENCIES IN VIT D
• Osteomalacia (in adults)
• Softening of the bones →
deformities, pain, and easy
fracture
• Decreased serum calcium
and/or phosphorus,
increased alkaline
phosphatase
• Involuntary muscle
twitching and spasms
Fat-soluble vitamins
TOXICITIES IN VIT D
• Kidney stones, irreversible
kidney damage
• Muscle and bone weakness
• Excessive bleeding
• Loss of appetite
• Headache
• Excessive thirst
• Calcification of soft tissues
(blood vessels, kidneys,
heart, lungs)
• Death
Fat-soluble vitamins
VITAMIN E SOURCES
• Vegetable oils,
margarine, salad
dressing, nuts, seeds,
wheat germ, dark
green vegetables,
whole grains, fortified
cereals
Fat-soluble vitamins
VITAMIN E FUNCTIONS
1. Stimulating calcium reabsorption from the
kidneys
2. Acts as an antioxidant to protect vitamin A
and Poly Unsaturated Fatty Acids (PUFA)
from being destroyed
3. Protects cell membranes
Fat-soluble vitamins
VITAMIN E DEFICIENCIES
• Increased RBC hemolysis (sickle-cell anemia)
• In infants, anemia, edema, and skin lesions
Fat-soluble vitamins
VITAMIN E TOXICITIES
• Relatively nontoxic
• High doses enhance action of anticoagulant
medications
Fat-soluble vitamins
VITAMIN K SOURCES
• Bacterial synthesis
• Green leafy vegetables, liver, eggs,
vegetables of the cabbage family
Fat-soluble vitamins
VITAMIN K FUNCTIONS
1. Synthesis of blood clotting proteins
2. Bone protein that regulates blood calcium
Fat-soluble vitamins
VITAMIN K
• Deficiency
Hemorrhaging
• Toxicity
No symptoms have been observed from
excessive vitamin K
Water-soluble vitamins
THIAMIN (VITAMIN B1) SOURCES
• Whole grain and enriched breads and
cereals, liver, nuts, wheat germ, dried peas
and beans
Water-soluble vitamins
THIAMIN (VITAMIN B1) FUNCTIONS
1. Coenzyme in energy metabolism
2. Promotes normal appetite and nervous
system functioning
Water-soluble vitamins
THIAMIN (VITAMIN B1)
DEFICIENCY
Beriberi
Mental confusion
(decrease in short term memory)
Fatigue, apathy
Peripheral paralysis
Muscle weakness and wasting
Painful calf muscles
Anorexia, weight loss
Edema
Enlarged heart
Sudden death from heart failure
Water-soluble vitamins
RIBOFLAVIN (VITAMIN B2) SOURCES
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Milk and other dairy
products
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Whole grain and
enriched breads and
cereals
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Eggs, meat, green
leafy vegetables
Water-soluble vitamins
RIBOFLAVIN (VITAMIN B2) FUNCTIONS
• Coenzyme in energy metabolism
• Aids in the conversion of tryptophan into
niacin
Water-soluble vitamins
RIBOFLAVIN (VITAMIN B2) DEFICIENCIES
Ariboflavinosis
Dermatitis
Photophobia
Cheilosis
Glossitis
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Reddening of the cornea
Water-soluble vitamins
NIACIN (VITAMIN B3) SOURCES
• All protein foods, whole grain and enriched
breads and cereals
Water-soluble vitamins
NIACIN (VITAMIN B3) FUNCTIONS
1. Coenzyme in energy metabolism
2. Promotes normal nervous system
functioning
Water-soluble vitamins
NIACIN (VITAMIN B3) DEFICIENCIES
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Pellagra: 4 (Ds)
Dermatitis (bilateral
and symmetrical)
and glossitis
Diarrhea
Dementia,
irritability, mental
confusion →
psychosis
Death, if untreated
Water-soluble vitamins
NIACIN (VITAMIN B3) TOXICITIES
• Flushing
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Liver damage
Gastric ulcers
Low blood pressure
Diarrhea, nausea, vomiting
Water-soluble vitamins
VITAMIN B6 (PYRIDOXINE) SOURCES
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Meats
Fish
Poultry
Fruits
Green Leafy Vegetables
Whole Grains
Nuts
Dried Peas And Beans
Water-soluble vitamins
VITAMIN B6 (PYRIDOXINE) function
1. Coenzyme in amino acid and fatty acid
metabolism
2. Helps convert tryptophan into niacin
3. Helps produce insulin, hemoglobin, myelin
sheaths and antibodies
Water-soluble vitamins
VITAMIN B6 (PYRIDOXINE) deficiency
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2.
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4.
5.
6.
Dermatitis
Cheilosis
Glossitis
Abnormal Brain Wave Pattern
Convulsions
Anemia
Water-soluble vitamins
VITAMIN B6 (PYRIDOXINE) toxicity
1.
2.
3.
4.
5.
Depression
Fatigue
Irritability
Headaches
Sensory Neuropathy Characteristic
Water-soluble vitamins
FOLATE SOURCES
Leafy vegetables
Dried peas & beans; Seeds
Liver
Orange juice
Breads & Cereals
Water-soluble vitamins
FOLATE FUNCTIONS
• Coenzyme in DNA synthesis, therefore vital
for new cell synthesis and the transmission
of inherited characteristics
Water-soluble vitamins
FOLATE DEFICIENCIES
Glossitis
Diarrhea
Macrocytic Anemia (megaloblastic anemia)
Depression
Mental Confusion
Fainting
Fatigue
FOLATE Deficiency
• Spina bifida(a neural tube defect) is one of the
diseases that are caused by folate deficiency
among pregnant women that affect new
births
Water-soluble vitamins
FOLATE TOXICITY
Too much can mask B12 deficiency
Water-soluble vitamins
VITAMIN B12 (CYANOCOBALAMIN) SOURCES
• Animal products: meat, fish, poultry,
shellfish, milk, dairy products, eggs
Water-soluble vitamins
VITAMIN B12 (CYANOCOBALAMIN) FUNCTIONS
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2.
3.
4.
Coenzyme in the synthesis of new cells
Activates folate
Maintains nerve cells
Helps metabolize some fatty acids and
amino acids
Water-soluble vitamins
VITAMIN B12 DEFICIENCIES
1. GI changes: glossitis,
anorexia, indigestion,
recurring diarrhea or
constipation, and weight loss
2. Macrocytic anemia
(pernicious anemia): pallor,
dyspnea, weakness, fatigue,
and palpitations
3. Neurologic changes:
paresthesia of the hands and
feet, decreased sense of
position, poor muscle
coordination, poor memory,
irritability, depression,
paranoia, delirium, and
hallucinations
Water-soluble vitamins
VITAMIN C SOURCES
Citrus fruits and juices
Red and green peppers
Broccoli
Cauliflower
Brussels sprouts
Cantaloupe
Kiwifruit
Mustard greens
Strawberries
Tomatoes
Water-soluble vitamins
VITAMIN C FUNCTIONS
1.
2.
3.
4.
Collagen synthesis
Antioxidant
Promotes iron absorption
Involved in the metabolism of certain
amino acids
5. Thyroxin synthesis
6. Immune system functioning
Water-soluble vitamins
VITAMIN C DEFICIENCIES
• Bleeding gums, pinpoint
hemorrhages under the skin
• Scurvy, characterized by
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Hemorrhaging
Muscle degeneration
Skin changes
Delayed wound healing:
reopening of old wounds
– Softening of the bones →
malformations, pain, easy
fractures
• Soft, loose teeth
• Anemia
• Increased susceptibility to
infection
• Hysteria and depression
Water-soluble vitamins
VITAMIN C TOXICITY
Diarrhea
Abdominal cramps
Nausea
Headache
Insomnia
Fatigue
Hot flashes
Aggravation of gout symptoms
Summary – Classic deficiency states
Disease
Vitamin Deficiency
Scurvy
Vitamin C
Beriberi
Thiamin
Pellagra
Niacin
Rickets (Children)
Vitamin D
Osteomalacia (adults)
Vitamin D
Pernicious Anemia
Vitamin B12
Post-Lecture Evalution: Match column
A with Column B
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2.
3.
4.
5.
6.
7.
8.
9.
B1 (Thiamin)
B2 (Riboflavin)
B3 (Niacin)
B6 (Pyridoxine)
B12 (Cobalamin)
C (Ascorbic acid)
D (Calciferol)
E (Tocopherol)
A (Retinoic acid)
1.
2.
3.
4.
5.
6.
7.
Pellagra: B3
Beriberi: B1
Sickle cell: E
Penicious: B12
Fe deficiency: C
Scurvy: C
Hypercholesterolemia:
B3
8. Hemorrhage: K
9. B2: Cheilosis,
photophobia
Thank You!