vitamin c, sources, functions,deficiency

1. VITAMIN C or
ASCORBIC ACID

2. • Functions
• Clinical features & morphology of scurvy
Vitamin C

3. • Water soluble vitamin
• 70 percentage of vitamin C is lost in the
process of cooking
• Most animals & plants can synthesize ascorbic
acid from glucose
• Man, higher primates, guineapigs & bats
cannot synthesize ascorbic acid

4. Dietary sources of vitamin C
• Amla ( Indian gooseberry- 700 mg/100 g)
• Guava, lime, lemon
• Green leafy vegetables
• Milk &
• Animal products like liver & fish

5. Functions of vitamin C

6. 1. It can change between ascorbic acid &
dehydroascorbic acid
• Most physiological properties of vitamin are
explained by this redox system

7. 2 . Ascorbic acid is necessary for the post
transilational hydroxylation of proline & lysine
residues
lHydroxy proline & hydroxy lysine form cross links
in collagen- gives tensile strength to fibers
lThis process is necessary for the normal
production of supporting tissues like osteoid,
collagen, and intercellular cement substances of
capillaries

8. 3 . Tryptophan metabolism
l Hydroxylation of tryptophan to 5-hydroxy
tryptophan- formation of serotonin

9. 4 . Tyrosine metabolism
lOxydation of parahydroxyphenylpyruvate to
homogenitisic acid

10. 5 . Iron metabolism
lVit C reduces ferric iron to ferrous state, which
is preferentially absorbed from intestine

11. 6 . Hemoglobin metabolism
lReconversion of met-hemoglobin to
hemoglobin

12. 7 . Folic acid metabolism
lHelps the enzyme folate reductase to reduce
foluc acid to tetrahydrofolic acid
lThus helps in maturation of RBC

13. 8 . Steroid synthesis
lHas some role in adrenal steroidogenesis
lVit C is present in adrenal cortex- depleted by
ACTH stimulation

14. 9 . Stimulates phagocytic action of WBC

15. 10 . Vit C is concentrated in the lens of eye
Regular intake of vit C reduces risk of
cataract formation

16. 11 . Antioxidant property
lAbility to scavenge free radicals directly
lParticipate in metaboluc reactions that
regenerate antioxidant form of vit E

17. CLINICAL FEATURES &
MORPHOLOGY OF
SCURVY

18. lGross deficiency of vit C
lCharacterised by bone diseases in growing
children & by hemorrhages & healing defects
in both children & adults

19. SYMPTOMS OF SCURVY
• Symptoms of scurvy generally develop after 3
months of severe or total vit C deficiency, they
include;
lWekness & fatigue
lBruising easily & bleeding from weakened blood
vessels, conn: tissue & bones due to collagen loss
lHair & teeth loss
lGingivitis: gums become painful, swollen &
spongy

20. • Infantile scurvy (Barlow's disease): infants
have pain when they move & lose their
appetite.
• Infants do not gain weight as they normally do
• In infants & children bone growth is impaired
& bleeding & anemia may occur
• In infants between 6 to 12 months of age diet
should be supplemented with vitamin C
sources

21. • Hemorrhagic tendency: collagen is abnormal
& intercellular cement substance is brittle. So
capillaries are fragile, bleed under minor
pressure
• Subcutaneous hemorrhage manifested as
petechiae in mild deficiency & as ecchymoses
or hematoma in severe conditions
• In severe cases hemorrhage may occur in the
conjunctiva & retina.

22. • In bones, deficiency results in failure of
osteoblast to form the intercellular ground
substance osteoid
• The resulting scorbutic bone is weak &
fractures easily
• Hemorrhage into joint cavity lead to painful
swelling of the joint

23. • Microcytic hypochromic anemia is seen
• Poikilocytosis & anisocytosis are also common
• Reason for anemia may be:
• -loss of blood by hemorrhage
• -decreased iron absorption
• -decreased THFA

26. OBESITY

27. Obesity
• Pathogenesis
• Metabolic changes

28. • Obesity is defined as a state of increased body
weight, due to adipose tissue accumulation, that
is of sufficient magnitude to produce adverse
health effects
• One method to measure fat accumulation is to
find the Body Mass Index(BMI)
• BMI- (wt in kg)/ (height in meters)2
• Normal range- 18 to 25 kg/m2
• 25-30-overweight, greater than 30 kg/m2-obesity

29. • Obesity results when-
• -calorie intake exceeds utilisation
• -lnactivity & sedentary lifestyle
• -genetic predisposition
• -diseases like hypothyroidism & cushing's
disease

30. PATHOGENESIS
• Adipose mass is increased due to enlargement
of adipose cells due to excess lipid deposition
& increase in number of adipocytes
• Excess consumption of nutrients

31. MORPHOLOGIC FEATURES
• Increased adipose stores in subcutaneous
tissues, skeletal muscles & internal organs like
kidneys, heart, liver & omentum
• Fatty liver is more common

32. MATABOLIC CHANGES
1 . Hyperinsulinemia
Hyperglycemia due to a state of insulin
resistance
2 . Type 2 DM
Obesity exacerbate the diabetic state

33. 3 . Hypertension
Due to increased blood volume
4 . Hyperlipoproteinemia
Normally plasma cholesterol circulates in
blood as LDL
Obesity associated with VLDL & mildly with
LDL

34. 5 . Atherosclerosis
Risk of MI & stroke
6 . Nonalcoholic fatty liver
May progress to cirrhosis
7 . Cholilithiasis
8 . Hypoventilation syndrome (pickwickian
syndrome)

35. 9 . Osteoarthritis
Due to wear & tear following trauma to joints
10 . Cancer

36. THANK YOU