2. Organic
nutrients
Have no energy
value , not
structural
component of
tissues
Essential
nutrient
Vitamins
Are required in small amount for different
biochemical reactions to support
normal growth, maintenance &
reproduction
3. Sources of vitamins
8/3/2020Footer Text 3
Exogenous
source:
Diet Endogenous source:
i. Intestinal flora :
Vitamin K, B12, Biotin
ii. Steroid precursor in
skin: Vitamin D
iii. Tryptophan (AA):
Niacin
4. - Maintains optimum health
- Prevents acute deficiency
disorders
Intermediary metabolism &
energy release
Prophylactic use to prevent
chronic diseases Antioxidant function
Functions of
Vitamins
6. 6
Fat soluble vitamins
ī§ Hydrophobic, soluble in
fat solvent
ī§ Intestinal absorption
depends on fat absorption
ī§ LP / specific protein is
needed for transport in
blood
ī§ Not readily excreted in
urine
ī§ Storage : Significant, in
Liver & adipose tissues
ī§ Regular dietary supply :
Not needed
ī§ Toxicity: Common
ī§ Only vitamin K has
coenzyme activity
Water soluble vitamins
ī§ Hydrophilic, soluble in water
ī§ Intestinal absorption doesnât
depend on fat absorption
ī§ No need of LP/ specific
protein for transport in blood
ī§ Readily excreted in urine
ī§ Storage : Limited except for
vitamin B12 & folic acid (in
liver)
ī§Regular dietary supply :
Needed
ī§ Toxicity: Rare
ī§ Coenzyme activity: Common
8. 8/3/2020Footer Text 8
Vitamin Chemical name Active / Functional /
Coenzyme form
B1 Thiamine Thiamine pyrophosphate
(TPP)
B2 Riboflavin FAD (Flavin adenine
dinucleotide), FMN
B3 Niacin/ Nicotinic
acid/ Nicotinamide
NAD (Nicotinamide adenine
dinucleotide), NADP
B5 Pantothenic acid Coenzyme A (CoA-SH), Acyl
carrier protein (ACP)
B6 Pyridoxine Pyridoxal phosphate (PLP)
B7 Biotin Biotin
B9 Folic acid / Folate Tetrahydrofolate (FH4)
B12 Cobalamin Methyl cobalamin,
5â-Deoxy adenosyl
cobalamin
9. 8/3/2020Footer Text 9
These vitamins are chemically
not related to one another.
They are grouped together,
because,
all of them function in the cells
as coenzymes.
13. 8/3/2020Footer Text 13
B1 /
Thiamine
(TPP)
In glucose oxidation:
a. In oxidative decarboxylation reaction:
īŧ PDH: Pyruvate to Acetyl CoA & CO2
īŧ Îą-KGDH: Îą-KG to Succinyl CoA (in TCA
cycle)
b. For Transketolase enzyme of HMP shunt
Helps to
- maintain nerve conduction
&
- functioning of nervous system
14. Remember
ī§ Oxidative decarboxylation of pyruvate and Îą-KG have
key role in energy metabolism.
So, in thiamine deficiency, ATP production is decreased
with impaired cellular functions.
As glucose is the only fuel for neurons & as optimum
thiamine is specifically important for glucose oxidation,
the deficiency of thiamine will affect the activity of
nervous system.
14
15. ī§ Impaired oxidation of pyruvate to acetyl CoA forces the
pyruvate to be converted to lactate.
This lactate acts as vasodilator leading to increased venous
return, high output heart failure and edema.
ī§ Thiamine is useful in the treatment of beriberi, alcoholic
polyneuritis, neuritis of pregnancy /old age.
15
16. 8/3/2020Footer Text 16
B2 /
Riboflavin
(FMN,
FAD)
Concerned with energy metabolism
Coenzyme in oxidation â reduction process /
dehydrogenation process:
e.g.
- Oxidation of succinate to fumarate
- Oxidation of fatty acyl CoA to ι, β fatty acyl
CoA
17. 8/3/2020Footer Text 17
B3 / Niacin
(NAD,
NADP)
Same as Riboflavin
e.g.
- Oxidation of malate to oxaloacetate
- Oxidation of pyruvate to acetyl CoA etc
B5 /
Pantothenic
acid
(CoA-SH)
Formation of :
i) Active acetate (acetyl CoA):
īŧ For synthesis of FA, Ketone bodies,
cholesterol etc
īŧ Oxidizes in TCA cycle
ii) Active succinate (succinyl CoA):
īŧ For synthesis of heme
īŧ ketolysis
Helps in fatty acid oxidation
18. Therapeutic use of vit.B3
In the reduction of:
- Plasma LDL-C
- Plasma TAG
18
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B6 /
Pyridoxine
(PLP)
Coenzyme for transamination &
deamination of amino acids (Main
function)
Coenzyme of phosphorylase during
Glycogenolysis:
Decarboxylation of :
īŧ Histidine : to produce histamine
īŧ Glutamate: to produce GABA
Synthesis of :
īŧ Porphyrin & heme
īŧ Catecholamine
īŧ Serotonin
20. Causes of deficiency of vit. B6
ī§ Treatment of TB with Isoniazid (INH): Common cause
ī§ Rare causes:
Newborn infant fed with infant formula, women taking OCP,
Alcoholics.
20
21. Link of INH with vit. B6 deficiency
ī§ INH forms an inactive derivative with Pyridoxal
phosphate.
So, it is recommended to prescribe B6 rich diet during
treatment with INH
21
22. 8/3/2020Footer Text 22
B7 / Biotin
(Biotin)
Coenzyme of carboxylase (to catalyze
carboxylation reaction)
e.g.
- Pyruvate to oxaloacetate
- Acetyl CoA to Malonyl CoA
23. Biotin Antagonist
Avidin (protein present in egg white) :
It tightly binds with biotin hampering absorption of biotin.
So, addition of raw egg white in diet may cause biotin
deficiency
23
24. 8/3/2020Footer Text 24
B9 / Folic
acid
(FH4)
Acts as a carrier of 1-C units (CH3, CH2
group etc) from different amino acids to
use them for synthesis of :
īŧ Purines
īŧ Pyrimidines (dTMP)
īŧ DNA, RNA
īŧ Methionine etc
Helps in neural tube development in early
fetal life
25. Storage of Folic acid
ī§ In liver to some extent
ī§ Total body store is 12-15 mg
ī§ This amount can support body demand for 4-6 months
after stoppage of folic acid intake.
25
26. 8/3/2020Footer Text 26
B12 /
Cobalamin
(Methyl
cobalamin,
5â-Deoxy
adenosyl
cobalamin)
[Synonym:
ī§Extrinsic
factor of
castle
ī§Antipernicio
us anemia
factor]
Interconversion of homocysteine &
methionine reaction: This reaction helps to
īŧ maintain methionine store
&
īŧ ensure availability of FH4 & FH4
subsequently participates in purine, dTMP &
NA synthesis
Conversion of propionyl CoA to succinyl
CoA : Succinyl Co A enters TCA cycle
Maintains Myelin sheath & Epithelial cells
Hemopoiesis by ensuring availability of
FH4
29. Functional types of vit. B12
ī§ Cyanocobalamin: This is the commercial form.
ī§ Methyl cobalamin: It is the main circulating form.
ī§ 5â-deoxy adenosyl cobalamin: It is the main storage form.
ī§ Hydroxy cobalamin: Injectable preparations are in this
form.
29
30. Absorption & transport of vit. B12
ī§ Requires Intrinsic Factor for absorption
ī§ Is transported in blood with a protein called
transcobalamin.
30
31. Storage of vit. B12
ī§ Stored in liver ,
ī§ Total body store: 4-5 mg
ī§ Stored vitamin B12 is not depleted until 5-6 years after
cessation of intake or absorption
31
35. 8/3/2020Footer Text 35
Vitamin Deficiency
B3 / Niacin Pellagra , featured by 3 âDâ
īŧ Dermatitis
īŧ Diarrhoea
īŧ Dementia
B5 /
Pantothenic
acid
ī§ Peripheral nerve damage
ī§ Burning feet syndrome
ī§ Staggering gait
B6 / Pyridoxine ī§ Peripheral neuropathy: Due to lack of
serotonin, GABA, Catecholamine
ī§ Anemia: Due to lack of heme synthesis
ī§ Disorders of AA metabolism
36. 8/3/2020Footer Text 36
Vitamin Deficiency
B7 / Biotin ī§ Dermatitis
ī§ Glossitis
ī§ Nausea, anorexia
ī§ Impairment of carbohydrate & fat
metabolism
B9 / Folic
acid
ī§ Megaloblastic anemia : Failure of rapid
DNA synthesis
ī§ Growth failure
ī§ GIT disturbances
ī§ NTDs in fetus during pregnancy like spina
bifida, anencephaly etc
ī§ Hyperhomocysteinemia
37. Causes of Folate deficiency
ī§ Increased physiological demand of folic acid
ī§ Lack of dietary intake
ī§ Malabsorption
ī§ Blood loss
ī§ Drugs
37
38. 8/3/2020Footer Text 38
Vitamin Deficiency
B12/
Cobalamin
ī§ Megaloblastic anemia:
īŧHappens due to 2ndary deficit of FH4 as a
result of folate trap
ī§ Neurological disorders:
Due to irreversible & progressive
demyelination.
e.g.
īŧ Sub acute combined degeneration of
spinal cord
īŧ Peripheral neuropathy
īŧ Dementia
īŧ Optic atrophy
ī§ Hyperhomocysteinemia & atherosclerosis:
Homocysteine level in blood is related with
MI.
44. 8/3/2020Footer Text 44
Chemistry Source Function
ī§Derivatives
of hexose
ī§A reducing
agent
(Benedictâs
test will be
positive )
īŧCitrus fruits
īŧGreen chili &
green leafy
vegetables
ī§ Post-translational
maturation of collagen:
Done by hydroxylation of
proline & lysine residues
of collagen
ī§ Enhances absorption of
iron
ī§ Reduces serum
cholesterol concentration
ī§Acts as anti-oxidant
ī§Helps in synthesis of
Catecholamine & Steroid
hormone
45. Therapeutic use of vit. C
Recommended for treatment of:
ī§ Ulcer
ī§ Trauma
ī§ Burns.
45
46. 8/3/2020Footer Text 46
Clinical manifestation of
vitamin C deficiency:
Scurvy
(Caused by defective collagen
synthesis following vitamin C
deficiency)
47. 47
īŧ Swollen, spongy and
bleeding gums
īŧ Loosened teeth
īŧ Fragile blood vessels
īŧ Bleeding under the skin
and in deep tissues
īŧ Cutaneous bleeding
leading to woody leg due to
capillary hemorrhage
īŧ Spontaneous bruising
īŧ Joint : Swollen, hemorrhage
īŧ Epistaxis
īŧ Hemorrhage in GIT
īŧ Slow wound healing
īŧ Anemia (iron deficiency anemia)