Transcript Vitaminler - mustafaaltinisik.org.uk

VITAMINS
Vijayalakshmi
INTRODUCTION
organic molecules with wide variety of capacities
prominent function - cofactors for enzymatic
reactions
generally cannot be synthesized by mammalian
cells
Vitamins are usually supplied in the diet or in
dietary supplements
necessary for our growth, energy, and general
well-being
HISTORY
Ancient Egyptians
recognized night
blindness
1747-Scottish naval
surgeon James Lind
discovered the
unknown nutrient
(vitamin C) in citrus
foods prevented
scurvy
1753- Lind published his Treatise on the
Scurvy
1860- Louis Pasteur demonstrated that
microscopic organisms can cause diseases
1880- Christian Eijkman
vitamin-deficiency conditions in animals
on an experimental basis
1905- Julius Friedenwald and John Ruhräh
Beri-Beri is probably of microbic
origin
1906- Frederick Hopkin's - foods contain a
small amount of “growth factors”
1911- Casimir Funk discovered what he
termed "vitamines"
1919- “Eat and Be Healthy”, Virgil
MacMickle, M.D., of Portland
“ chemical substances of which the body is
composed are similar to those of the foods
which nourish it. They are made up of the
same chemical elements...the body can only
get these from foods...”
FUNCTIONS
Digestion
Converting food into energy
Cell division and growth
Tissue repair
Transporting oxygen and wastes in the
circulation
Immunity
FUNCTIONS
Mental alertness
Making hormones
Reproduction
Protecting the body from poisons
Neutralizing the harmful by-products of
metabolism such as free radicals
CLASSIFICATION
Water soluble
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Pantothenic acid (B5)
Pyridoxine (B6)
Biotin, Folic acid
Cobalamin (B12)
Ascorbic acid
Fat soluble
Vitamin A
Vitamin D
Vitamin E
Vitamin K
VITAMIN A
Vitamin A consists of
three biologically
active molecules,
retinol, retinal and
retinoic acid
Retinol - “sticky” and
light sensitive
Provitamin A
carotenoids –
converted to retinol by
the body
ex- Beta (b)-carotene
Sources
milk, cheese, cream,
liver, kidney, cod and
halibut fish oil milk,
Beta carotene carrots, pumpkin,
sweet potatoes, winter
squashes, cantaloupe,
pink grapefruit,
apricots, broccoli,
spinach and most dark
green leafy vegetables
FUNCTIONS-VISION
RETINOL
retinyl ether
11-cis retinol
11-cis retinal
11-cis retinal goes to rod cells
and binds with protein
called opsin to form
visual pigment called rhodopsin
isomerization of 11-cis retinal to
all-trans retinal
Immunity- maintains integrity of skin and mucosal cells
- Development and differentiation of WBC- by
Retionic Acid
- activation of t-cells requires all-trans RA
binding
Growth and Development-embryonic development
• Regulation of expression of gene for growth
hormone
Red blood cell production
DEFICIENCIES:
Night Blindness- Bitot’s spot, Xeropthalmia
infectious disease – Diarrhea, respiratory diseases
VITAMIN D
synthesized only
when exposed to
sunshine.
Converted to active
form, 1a,25dihydroxyvitamin D
The 1a,25dihydroxyvitamin D
acts as a hormone,
and has a specific
nuclear receptor
SOURCES
Sunlight(PRIMARY)
MILK
PRODUCTS:Cheese,
butter, margarine,
cream, fortified milk
SEA FOODS :fish,
oysters
fortified cereals.
FUNCTIONS:
Calcium metabolism
Vitamin D endocrine system
- D3 bounds to vitamin D-binding protein and
transported to liver
- converted to 25-OH-D3 or calcidol (inactive)
- increase exposure of sunlight – increase blood level
of calcidol
- hydroxyled to 1,25-OH-D3 or calcitriol
- parathyroid hormone released
Vitamin D receptor – Vitamin D Receptor to Retinoic
Acid X Receptor to form heterodimer-interacts with
DNA
Vitamin D Responsive Elements - change in
transcription of a nearby gene.
Cell differentiation- proliferation
- psoriasis - the proliferation of skin cells called
keratinocytes
- identification of VDR in keratinocytes led to the use of
creams containing analogs of calcitriol in the
treatment of severe cases of psoriasis.
Immunity – WBC recognizes Antigens
- Autoimmune disease
- Immune responses are mediated by
T-Cells
DEFICIENCIES:
Rickets
Osteomalacia
VITAMIN K
The K vitamins exist
naturally as K1
(phylloquinone) in
green vegetables
K2 (menaquinone)
produced by intestinal
bacteria
K3 is synthetic
menadione.
SOURCE
Spinach, cauliflower
and other green leafy
vegetables
chief source of
vitamin K is synthesis
by bacteria in the large
intestine
FUNCTIONS
Coagulation (clotting)
- ability to bind Ca2+ required for activation of the 7
“vitamin k-dependent” clotting factor in the
coagulation cascade
- Factors II , VII, IX,X make up the core
- Protein Z enhances the action of thrombin by
promoting association with phospholipids
- Protein C and S control cascade
- Vitamin k-dependent factors synthesized in liver
Bone mineralization – Osteocalcin – Osteoblastsregulated by active form of vitamin D or calcitriol.
DEFICIENCIES
Liver disease
Poisoning with vitamin K antagonists
Hemorrhagic disease of the newborn results from
vitamin K deficiency in human infants
Increased risk of fractures or reduced bone density
may result from inadequate intake of vitamin K
VITAMIN E
Describes a family of 8
alpha, beta, gamma,
delta and 4 tocotrienols
Alpha tocopherol is the
only vitamin E that is
actively maintained in
human body found in
tissues and blood
Maintains integrity of
cell membrane and
protects fats from
oxidation
VITAMIN E
SOURCES:
Vegetable oils, nuts, egg
yolk, Parmesan,
chickpeas, wheat germ,
oatmeal, olives,carrots,
parsnips, red peppers,
green leafy vegetables,
sweet potatoes,
tomatoes, sweet corn
DEFICIENCIES:
Sever malnutrition
Genetic defects
Fat malabsorption
Neurological symptoms
VITAMIN B
THIAMIN B1
RIBOFLAVIN B2
NIACIN B3
PANTOTHENIC
ACID B5
VITAMIN B6
SOURCE DEFICIENCY
TYPE
FUNCTION
Whole
BERI-BERI
grains,
cereals,
legumes
nuts, lean
pork, yeast
Oxidationliver,
damage to
B2
reduction
eggs,
eyes, mouth,
Flavin
cheese,
and genitals
mononucleotide (redox)
reactions
milk and
Flavin adenine
Antioxidant cereals
dinucleotide
functions
B1
Thiamin
pyrophosphate
Coenzyme
non –
coenzyme
function
NIACIN
found in fish,poultry, meat, nuts and eggs
Niacin is required for the synthesis of of the
active form of vitamin B3
NICOTINAMIDE ADENINE
DINUCLEOTIDE
Deficiency disease is pellagra
VITAMIN B6
PYIDOXAL, PYRIDOXAMINE and
PYRIDOXINE
Protein metabolism
Deficiencies are rare and usually related to
overall deficiency of all the B-complex
vitamins.
VITAMIN C
derived from glucose
via the uronic acid
pathway
extracted from plant
sources such as rose
hips, blackcurrants or
citrus fruits
easily oxidised in air
SOURCES
Broccoli, Brussels
sprouts, cauliflower,
cabbage, mange tout,
green leafy vegetables,
red peppers, chilies,
watercress, parsley,
blackcurrants,
strawberries, kiwi
fruit, guavas, citrus
fruit.
VITAMIN C
FUNCTIONS:
synthesis of collagen, neurotransmitter,
norepinephrine
protects indispensable molecules
regenerate other antioxidants such as vitamin E
DEFICIENCY:
Scurvy