2. •Fat soluble vitamins are soluble in fat and are
absorbed by intestine, with the help of dietary
fat. These include vitamins A, D, E and K
3. VITAMIN A
• Vitamin A refers to a group of three compounds, collectively
called retinoids.
• These include retinol (vitamin A alcohol), retinal (vitamin A
aldehyde or retinaldehyde) and retinoic acid (vitamin A
acid).
• In addition, plants contain a group of compounds called
carotenoids. They yield retinoids, when metabolized in the
body and, are called as precursors of vitamin A.
4. Recommended daily allowances
• .Average daily requirement of vitamin A for adults is 600 ug.
• 950 ug during pregnancy and lactation.
• Children 300 to 600microgram
5. Dietary sources
• Animal foods,
• liver, cod liver oil, egg yolk and milk, are rich sources
of retinoids.
• Plant sources
• • Dark green and yellow-orange vegetables, such as
carrots, spinach and broccoli, and orange colored
fruits, like peaches, apricots and mango, are good
sources of carotenoids.
6. Functions
• Vitamin A is essential for normal structure and
functions of the skin and mucous membranes, such as
eyes, lungs and digestive system.
• , vital for vision, embryonic development, growth and
cellular differentiation, and immune system.
• Retinal is essential for night and color vision.
7. • Retinol is required in reproduction and bone health.•
• Retinoic acid is important for cellgrowth
• Carotenoids function as antioxidants and prevent
damage by free radicals.
• to prevent damage from chemical carcinogens and
lower the risk cancer.
8. synthesis, metabolism, storage and excretion
• Retinoids and carotenoids incorporates with lipids,
and passive absorption occurs into the mucosal cells
of the small intestine
• . They are incorporated into chylomicrons for
transport into the lymph and, eventually, the
bloodstream
9. • The liver plays an important role in vitamin A
transport and storage.
• • Retinol is oxidized to retinal and then to retinoic
acid, or conjugated into retinyl glucuronide or retinyl
phosphate.
• Oxidized forms of vitamin A are excreted in the urine
• while intact forms are excreted in the bile and feces.
10. • Retinoids and caratinoids +lipids. passive transport small
intestine. Lymph. blood portal circulation. liver
oxidation. Retinal. retinoic acid excess of retinoids conjugated
retinyl glucuronide and retinyl phosphate. excreted in urine and in
fecas
11. Deficiency diseases
• Vitamin A deficiency causes night blindness (impaired
adaptation to lowintensity light), which can subsequently
lead to xerophthalmia (dryness of the conjunctiva and
cornea) and blindness ,
• Vitamin A deficiency also affects production of sperm, in
men. Women can become infertile, possibly, due to
disruption in the production of the reproductive tract
secretions. .
• Vitamin A deficiency also reduces the number of T-
lymphocytes.
12. • Causes bacterial, parasitic and viral infections.
• Children with lack of vitamin A are at higher risk of diarrhea,
respiratory tract infections and measles.
• Vitamin A deficiency also retards growth and development,
and leads to bone deformities.
13. Hypervitaminosis
• Vitamin A toxicity, with megadoses of supplements, can
cause symptoms, such as fatigue, vomiting, abdominal
pain, bone and joint pain, loss of appetite, skin disorders,
headache and blurred vision.
• Excess doses of vitamin A, prior to conception and in the first
few months of pregnancy, can cause spontaneous abortions.
• Hypervitaminosis A is teratogenic, and can lead to birth
defects including cleft palate, heart abnormalities and brain
malfunctions. .
14. VITAMIN D
• Vitamin D is a sterol (steroid alcohol), also called as sunshine vitamin.
exhibit antirachitic properties,
• Vitamin D2 (ergocalciferol) found in plant foods,
• Vitamin D3 (cholecalciferol) found in animal foods
• synthesized in the skin
• . Vitamin D acts as a precursor to the hormone, calcitriol (1,25-
dihydroxycholecalciferol), involved in calcium synthesis, that is
essential for bone mineralization and neuromuscular functions.
15. Recommended daily allowances
• breast fed infants, who receive little exposure to
sunlight, need 5 mg (200 IU) of vitamin D per day (1
mg = 40 IU)
• . For elder people recommended daily intake is 10 mg
(400 IU.)
16. Dietary sources
• Most of the vitamin D, is obtained through the action
of sunlight on skin
• . Major dietary sources
• cod liver oil, fish oil, egg yolk and liver.
• fortified milk and foods.
17. functions
• Primary role of vitamin D is to regulate blood calcium
level
• . Calcitriol, the hormone synthesized from vitamin D,
along with parathyroid hormone and calcitonin,
regulates blood calcium levels through its action on
bone, kidneys and small intestine
• , vitamin D inhibit cell proliferation and enhance cell
differentiation. .
18. Absorption, Synthesis, Metabolism, Storage
and Excretion
• Dietary vitamin D is incorporated with lipids ,as
chylomicrons absorbed in the intestine, by passive
diffusion
• enters the lymphatic system and then , enters
plasma, blood
• it is delivered to the liver by chylomicron
• to the specific carrier vitamin D-binding protein
(DBP).
19. • Vitamin D from food.+lipids Passive diffusion. Absorbed in small
intestine Chylomicroms with vitamin D. Lymph. Blood. Portal
circulation. Liver. 25 hydroxyvitamin D3(25- hydroxycalceferol)/.
• Lymph blood Vitamins D binding proteins stored in the
peripheral tissues
• 25 hydroxyholecalciferol. acted upon by the alpha _1_
cholecalciferol. 1,25-dihydroxycolcalceferol (calcitriol). Excess
is excreted in urine
20. • .Vitamin D is transported by DBP, delivered to the peripheral
tissues
• Vitamin D, is also synthesized and stored in the skin from 7-
dehydrocholesterol (provitamin D)
• .In the liver it is converted to 25-hydroxyvitamin D3
(25hydroxycholecalciferol).
• Stored vitamin D is .acted upon, by the enzyme alpha-
1hydroxylase in the kidney, it is converted to calcitriol [1,
25-dihydrocolcalceferol) the most active form of the
vitamin.
21. • Deficiency disorders
• Prolonged deficiency of vitamin D, in children leads to
rickets.
• bone pain, poor growth and deformities of the
skeleton, bowed legs, curvature of the spine, and
thickening of the ankles, wrists and knees
• . Ends of the long bones become soft and bulky,
characteristic of bowed-legs and knock-knees.
• extreme stunting of growth
22.
23. • In adults,
• . Deficiency can lead to osteomalacia, also referred to
as adult rickets.
• symptoms include increased bone degeneration,
leading to pain bones and muscle weakness.
24. Hypervitaminosis
• Excessive dietary vitamin D intake lead to hypercalcemia
(high calcium level in the blood)
• . Hypercalcemia can result in deposition of excess calcium in
soft tissues and heart and kidney damage
• . affect nervous system, causing severe depression
• GIT disturbances (nausea, vomiting and loss of appetite).
25. VITAMIN E
• Vitamin E refers to a group of several lipid soluble
compounds synthesized by plants, such as
tocopherols and tocotrienols.
26. Recommended daily allowances
•
• : Average daily requirement of a tocopherol, for
adults, is 5-10 mg
• Its requirement is increased to about 20 mg, during
lactation.
27. Dietary sources
• Wheat germ oil is the richest source of vitamin
• , vegetable oils, such as safflower oil, cottonseed oil
and sunflower oil, and nuts and seeds, are good
sources of vitamin E.
28. Functions
• . Vitamin E acts as an antioxidant
• .• It stabilizes cell membrane and prevents cells from
damage by free radicals
• Cells damaged by free radicals, are prone to
mutations, thus,vitamin E helps to prevent cancer
• .
29. absorbtion .metabolism.storage.and excretion
• Vitamin E is absorbed in the upper small intestine.
• Absorbed vitamin E is incorporated into chylomicrons
• transported into lymph and then enters blood
• • It is delivered to the liver and is incorporated into
VLDL
• . Within the cells, intracellular transport of the
tocopherol requires an intracellular tocopherol
binding protein (TBP).
30. • Adipose tissue stores about 90% of the vitamin E
• .Vitamin E is oxidized, conjugated with glucuronic acid
and secreted in the bile and excreted in the faeces.
..Excreted in the urine as water soluble metabolites
31. • Vit E with lipids Passive diffusion. Small intestine Chylomicrons.
Lymph. Blood. Portal circulation. Liver. Vit E+VLDL.
Tocopherol binding proteins. Intracellular transport. Adipose
tissues . Oxidised and conjugated. Vitamin E glucuronic acid.
Excreted in bile and through fecal matter and through urine
32. Deficiency diseases
• Vitamin E deficiency seen in persons with fat
malabsorption syndrome, such as cystic fibrosis
• .premature hemolysis
• neurological problems that affect spinal cord and
peripheral nerves.
33. Hypervitaminosis
• High doses of vitamin E have negative effects on
other fat soluble vitamins
• Vitamin E interferes with the absorption of vitamin
k
• .Large doses of vitamin E is hazardous to people
taking anticoagulant medication, such as warfarin
and aspirin.
34. VITAMIN K
• Vitamin K refers to a family of compounds known as
napthoquinones.
• These include vitamin K1 (phylloquinone) obtained from
plant sources),
• vitamin K2 (menaquinone), obtained from animal sources
and synthesized by intestinal bacteria)
• vitamin K3 (menadione), available commercially
•
35. Recommended daily allowances
• Daily intake of vitamin K for adults, is 60-100 ug.
• Dietary sources
• Intestinal bacteria can synthesize and meet about 10-15% of
the daily requirement of vitamin K
• .. Green leafy vegetables like spinach, broccoli, vegetable
oils like soybean oil, cottonseed oil
• .Animal products, milk and milk products
36. Functions
• It is required for blood-clotting for the production of
prothrombin, factor VIII, factor IX and factor X, and
fibrin
• . Vitamin K also helps to make osteocalcin, which is
required for mineralization and maturation of bone.
37. Absorption, storage, metabolism and excretion
• Vitamin K is absorbed in small intestine, and colon by
passive diffusion.
• Absorbed vitamin is incorporated into chylomicrons in the
lymph, enter plasma
• taken to the liver, where it is incorporated into LDL
• delivered to peripheral tissues by LDL.
• metabolites are excreted in the faeces, via the bile.
• .Menadione is excreted, in the urine as a phosphate, sulfate
or glucuronide derivative
38. • Vit K with lipids Passive diffusion. Small intestine and colon
Chylomicrons. Lymph. Blood. Portal circulation. Liver. Vit
k+LDL. Peripheral tissues Oxidised and conjugated. Vit k
gucoronic acid Excreted in bile and through fecal matter and
through urine as phos phates ,sulfates, glucuronide derivatives
39. Deficiency diseases
• Vitamin K deficiency seen in fat malabsorption
syndromes, such as celiac disease, , cystic fibrosis
• prolonged use of antibiotics, which destroys intestinal
bacteria.
• People who are on anticoagulants
• the newborn babies also have a risk of vitamin K
deficiency (since newborn babies lack intestinal
bacteria).
40. Deficiency disorders
• Bleeding disorders
• Easy bruising
• Oozing from the nose or gums
• Excessive bleeding from GI tract
• Blood in the urine and stool
• Heavy menstrual bleeding
