3. INTRODUCTION
• Vitamin D is a fat soluble vitamin.
• The term “Vitamin D” refers to a family of related compounds
biosynthesized from cholesterol and ergosterol.
• Vitamin D is a sterol, it contains a steroid nucleus.
• Vitamin D functions like a hormone.
FORMS OF VITAMIN D :
• Vitamin D in the diet occurs in two forms:
• Vitamin D2 (ergocalciferol) is the form of vitamin D synthesized
by certain fungi and is used in many supplements.
• Vitamin D3 (cholecalciferol) is synthesized from 7-
dehydrocholesterol in sun-exposed skin and found naturally in
animal products such as eggs, fish and liver.
5. (Ergocalciferol)
VITAMIN D2
(Cholecalciferol)
VITAMIN D3
Found in plant lifeSynthesized in the body
Synthetically derived
supplement
Naturally derived
supplement
Moderately increases vitamin
D levels in the body
Significantly increases
vitamin D levels in the body
Alternative form appropriate
for vegetarians
Recommended by experts
for optimal bone and immune
support
6. SOURCES
• In addition to sunbathing:
• Various fish species(salmon,
sardines and mackerel), fish oil,
cod liver oil, egg yolk.
• Eggs, beef liver, mushrooms etc
• Milk is a poor source of Vitamin
D
7. METABOLISM
In the subcutaneous tissue of our
skin 7-dehydrocholestrol is
present when UV light
(UVB 290-315nm) falls
converts 7-dehydrocholestrol into
cholecalciferol (inactive form)
LIVER (25 hydroxylase)
converts cholecalciferol into 25
hydroxycholecalciferol (calcidiol)
KIDNEY (1 hydroxylase)
converts 25 hydroxy
cholecalciferol into 1, 25
dihydroxycholecalciferol
(calcitriol)[ACTIVE FORM]
8.
9. Regulation of plasma Calcium
• When the Calcium levels in the blood fall(hypocalcemia), the
Parathyroid hormone is released which increases the
production of Vit D and helps in release of calcium from the
bones(osteoblast), increase calcium uptake by the intestine and
increase calcium reabsorption from urine.
FUNCTIONS
11. ACTION ON INTESTINE
• Calcitriol increases the intestinal absorption of calcium
and phosphorous.
• In the intestinal cells calcitriol binds with a cytosolic
receptor(VDR) to form calcitriol-receptor complex.
• This complex then approaches the nucleus and
interacts with specific DNA leading to the synthesis of
calcium binding protein(Calbindin).
• This protein increases the calcium uptake by the
intestine.
• Hence it acts as an hormone.
Functions conti…
12. ACTION ON BONE
• Calcitriol stimulates the osteoblasts for calcium uptake
and promote calcification when blood calcium level is
high.
• Mobilization of calcium from bones when calcium level
is low in the blood.
ACTION ON KIDNEY
• Calcitriol increases the reabsorption of calcium and
phosphorous by renal tubules therefore both minerals
are conserved.
• Decrease excretion of calcium and phosphorous.
Functions conti…
14. PEOPLE AT GREATER RISK OF DEVELOPING
VITAMIN D DEFICIENCY
1. Newborn infants:
Who are absolutely breastfed require vitamin-D
supplements because mothers milk does
not contain significant levels of the vitamin.
2. Women after labor:
The serum concentration of Vitamin-D and
calcium falls rapidly
3.Dark-skinned individuals may require
extra vitamin D because melanin acts
like a sun-block, prolonging the time
required to generate vitamin D.
15. 4. Obese people have lower levels of the
circulating form of vitamin D, probably
because it is deposited in body fat
masses less bioavailable vitamin
D.
5. Patients with chronic liver disease due to
malabsorption.
6. Vitamin D is found only in animal foods.
strict vegetarian people sharply
increase the risk of deficiency if sunlight
exposure is inadequate.
16. CAUSES OF VITAMIN D DEFICIENCY
• Not exposed to sunlight (northern latitudes and winter).
• Bedridden for a long time.
• People who cover the whole body.
• Nutritional deficiency.
• Malabsorption of vitamin.
• Abnormal activation of Vitamin-D (liver and renal
diseases may decrease the hydroxylation).
18. RICKETS
• The classic Vitamin-D deficiency disease in children.
• The disease is characterised by bow legs or knocks
knees, curvature of the spine, and pelvic and thoracic
bone deformalities.
• Mainly due to the insufficient mineralization of the
bones.
• Serum calcium and phosphorous are low which is a
characteristic feature of rickets.
20. OSTEOMALACIA
• Found in adults.
• Osteon = bone
• Malakia = softness
• Bones are softened due to insufficient mineralization
and increased osteoporosis and prone to fractures.
• Biochemical parameters : low serum calcium,
phosphorous.
• Important cause of hip fractures after 60.
23. HYPERVITAMINOSIS
• Doses above 1500 IU/ day for long period may
cause toxicity.
• Symptoms : Nausea, loss of appetite, increased
thirst and loss of weight.
• Although Vit D is toxic in higher doses excessive
exposure to sunlight does not result in Vit D
toxicity, because excess D3 is destroyed by
sunlight itself.
25. INTRODUCTION
• It is the only fat soluble vitamin with a specific
coenzyme function.
• It is required for the production of blood clotting
factors, essential for coagulation.
• In German, its called Koagulation –hence called as
Vitamin-K
• Vitamin K are basically naphthoquinone derivatives.
CHEMISTRY
• Vitamin K exists in 3 different forms :
• Vitamin-K1
• Vitamin-K2
• Vitamin-K3
26. 1) Vit K 1 (Phylloquinone)
- natural form
- found in plants
- provides the primary source of vitamin K
to humans through dietary consumption
-have a 20C isoprenoid side chain
2) Vitamin K2 compounds (Menaquinones)
- made by bacteria in the human gut
- provide a smaller amount of the human
vitamin K requirement
-have a 30C isoprenoid side chain.
3) Vitamin K3 (Menadione)
-synthetic form of vitamin K
-it lacks the side chain and is water soluble.
Contin…
Vitamin K2
27. SOURCES
• Green leafy vegetables such as
Spinach, Green cabbage, Turnip,
Parsley, lettuce, beef liver, green
tea etc.
• Margarine and liver.
• Vegetable oils and particularly
olive, soyabean oils etc.
• Some amount is contributed by
intestinal bacteria.
28. Absorption, Transportation and Storage
• Absorption takes place in small intestine in the
presence of bile salts.
• The transportation from intestine is carried out through
chylomicrons.
• The storage occurs in liver and from liver transportation
to peripheral cells is carried out bound with beta
lipoproteins (VLDL).
30. FUNCTIONS OF VITAMIN K
Vitamin K is involved as a cofactor in the carboxylation of certain
glutamate residues in proteins to form γ- carboxyglutamate
residues(Gla-residues). Gla-residues are usually involved in
binding calcium and are essential for the following biological
activities:
1. Blood coagulation
Production of proteins that are part of the coagulation
cascade in the blood. Several proteins promote
coagulation(prothrombin II, VII, IX, X) while others slow it
down (proteins C and S). Thus, activity of vitamin K
balances the two opposing sides of coagulation system in
blood.
2. Bone metabolism
•Bone Gla-protein(Osteocalcin): Regulate incorporation of
calcium into bones.
•Matrix GLA protein (MGP): Clearance of extracellular
Calcium to protect against soft tissue calcification.
31.
32. • Bruising tendency, echymotic patches (bleeding
underneath the skin).
• Nosebleeds
• Bleeding gums
• Bleeding in stomach
• Blood in urine
• Blood in stool
• Extremely heavy menstrual bleeding
• In infants, may result in intracranial
hemorrhage.
• Hypoprothombinemia: increased blood
coagulation time.
CLINICAL MANIFESTATIONS
33. VITAMIN K DEFICIENCY IN INFANTS
Newborns are prone to vitamin K deficiency
because…
1. Vitamin K and lipids are not easily transported
across the placental barrier
2. Prothrombin synthesis in the liver is an
immature process in newborns, especially
when premature.
3. The neonatal gut is sterile, lacking the bacteria
that is necessary in menaquinone synthesis.
4. Breast milk is not a good source of vitamin K
Results in a hemorrhagic disease called vitamin K
deficiency bleeding (VKDB)
This disease is associated with breastfeeding,
malabsorption of lipids, or liver disorders.
34. • A normal diet containing the vitamin.
• Heavy alcohol consumption impairs the liver’s ability to
produce vitamin K-dependent coagulation factors and
impair recycling of vitamin K.
• Vitamin K can be given orally.
• In the case of someone who improperly absorbs fats or
is at a high risk of bleeding, Vitamin K can be injected
under the skin.
PREVENTION / TREATMENT
35. • It is recommended that all newborns are given an
injection of phylloquinone(Vitamin K1) into the
muscle to prevent intracranial bleeding after
delivery.
• Formulas for infants contain Vitamin K.
37. Quiz Time!
Where are the sources of Vitamin D?
Name the deficiencies caused by Vitamin D?
What is the active form of Vitamin D?
What are the different forms of Vitamin K?
What is the main function of Vitamin K?
