Vitamins are organic substances that are essential for carrying out normal biochemical processes and physiological functions. They are divided into fat-soluble vitamins (A, D, E, K) and water-soluble vitamins. Fat-soluble vitamins are stored in the liver and excessive intake can lead to toxicity, while water-soluble vitamins are excreted and toxicity does not occur. Vitamins must be activated in the body and deficiencies can cause specific syndromes, while adequate intake through a balanced diet meets daily requirements.

1. Vitamins

2. • Vitamins are organic substances that are essential for
carrying out the normal biochemical processes and
physiological functions of body.
• These are non-energy compounds and required in very
small quantities.
• The vitamins generally serve as cofactors for the enzymes
required in intermediary metabolism.

3. • The main source of vitamins is diet.
• A balanced diet supplies adequate amounts of vitamins to fulfill
the daily requirements.
• Humans cannot synthesize vitamins in the body except some
vitamins such as Vit. D in skin, and Nicotinamide from
tryptophan.
• Lack of particular vitamin leads to specific deficiency syndromes.
Vitamin deficiencies occur due to inadequate intake,
malabsorption, increased tissue needs, increased excretion,
certain genetic abnormalities and drug-vitamin interactions.

4. The vitamins have been broadly divided into
two groups:
Fat-soluble vitamins: vit. A, vit. D, vit. E and vit.-K.
These vitamins are stored by the body, mainly in the liver.
Excessive intake of these can lead to toxicity due to
accumulation, known as hypervitaminosis.
Water-soluble vitamins: vit B complex group, vit. C.
These vitamins are least stored and toxicity does not occur.
The excess of vitamins are rapidly metabolized and readily
excreted in the urine.

5. Vitamers
• The different chemical forms and precursors of a vitamin are known
as Vitamers of that particular vitamin.
• These vitamers have generally similar molecular structure and
show vitamin- activity in a vitamin deficient biological system.
• All vitamers may not possess equal vitamin potency.
Examples of vitamers include cyanocobalamin, hydroxocobalamin,
methylcobalamin and 5- deoxyadenosylcobalamin:- which are all
vitamers of Vit B12 and all possess B12 activity.
Similarly, both niacinamide and nicotinic acid are vitamers of vit-B3
(Niacin).

6. These vitamins need to be activated to their active forms in
the body for their actions. The active forms of some of the
vitamins are as follows:
Vitamins Active Forms
Vitamin-A Retinal(Stored as Retinol)
Vitamin-D 1,25 Dihydrocholecalciferol
Vitamin- E α-Tocopherol
Vitamin- K Napthaquinone
Vitamin-C L- Ascorbic acid
Vitamin-B1 (Thiamine) Thiamine pyrophosphate
Vitamin-B2 (Riboflavin) Flavin-mononucleotide (FMN)
Vitamin-B3 (Niacin) Nicotinamide adenine dinucleotide (NAD)
Vitamin-B5 (Pantothenic acid) Coenzyme-A
Vitamin-B6 (Pyridoxine) Pyridoxal phosphate
Vitamin-B9 (Folic acid) Tetrahydrofolate
Vitamin-B12 (Cynocobalamine) 5-Methyl cobalamine

7. FAT SOLUBLE VITAMINS

8. Vitamin- A
• There are various natural forms of Vitamin A (vitamers) such
as Retinol (vit A1), Dehydroretinol (vit A2) and Carotenoids.
• Dietary Sources: Carrot (richest plant source), red
cabbage, turnip, spinach, mango etc. are some of the plant
sources. Marine fish liver oil such as cod, halibut (richest
animal source), fresh water fish, egg yolk, milk, cheese,
butter are some of the animal sources.

9. Physiological functions:
• Essential for proper functioning of Rod cells in the visual
cycle; hence the night vision. Vision in the dim light
depends upon proper functioning of Rods. Prevents night
blindness and Xerophthalmia.
• Maintenance of normal epithelium all over body.
• As antioxidants (vitamin-A,C,E are more potent
antioxidants in nature) and anti cancer properties.
• Enhances immune functions and prevents recurrent
infections like measles, malaria and diarrhoea, etc.
• In reproduction, for normal spermatogenesis and foetal
development.
• Bone growth in children.

10. • Deficiency Symptoms: These are seen when there is a
long term deprivation and the stores are depleted. A
disturbance in the physiological roles manifests as the
deficiency symptoms.
Some of the symptoms are:
• Eye: Xerosis (dryness) of eye, ‘Bitot’s spots’,
keratomalacia (softening of cornea), corneal opacities,
night blindness (nyctalopia) progressing to total blindness.

11. • Epithelium: Dry and rough skin with papules
(phrynoderma), hyperkeratinization, atrophy of sweat
glands, keratinization of bronchopulmonary epithelium.
Increased tendency to urinary stone formation due to
shedding of ureteric epithelial lining which acts as a nidus.
• Immunity: increased susceptibility to infection such as
diarrhoea, measles etc.
• Reproduction: Sterility due to faulty spermatogenesis,
abortions, foetal malformations and growth retardation
etc.

12. Recommended dietary allowance (RDA)
• Daily requirement and for prophylaxis of vit A deficiency
during infancy, pregnancy, lactation, hepatobiliary
diseases, steatorrhoea: 3000–5000 IU/day.
• Treatment of established vit A deficiency: 50,000–100,000
IU i.m or orally for 1–3 days followed by intermittent
supplemental doses.
• Skin diseases like acne, psoriasis, ichthyosis. Retinoic
acid and 2nd or 3rd generation retinoids are used.

13. Hypervitaminosis-A
• It can occur due to regular intake of excessive vit-A
>100,000 IU /day for more than three weeks. The toxicity
symptoms commonly seen are nausea, vomiting,
headache (due to increased intracranial tension and also
known as Pseudotumor-cerebri ), itching, erythema,
dermatitis, exfoliation, hair loss, bone and joint pains, loss
of appetite, irritability, etc. Daily intake should not exceed
20,000 IU.

14. Vitamin-A has been included in National
Immunization Programme of India.
• A total 17-lac unit of vitamin-A is supplemented to child.
• A total of 9 mega doses are to be given from 9 months of
age to 5 years.
• 100,000 IU at 9 months with measles immunization,
• 200,000 IU at 16-18 months with DPT booster,
• 200,000 IU every 6 months upto the age of 5 years.

15. Vitamin- D
• Vitamin D is the collective name given to antirachitic
substances found in foods and synthesized in the body
and activated by UV radiation.
• D1: mixture of antirachitic substances found in food—only
of historic interest.
• D2: ergocalciferol or calciferol is made by UV irradiation,
eg. ergosterol in plants and also present in irradiated foods
such as yeasts, fungi, bread, milk etc..
• D3: cholecalciferol synthesized in the skin under the
influence of UV rays.

16. • Vitamin D2 and D3 undergo two successive
hydroxylations: first in the liver to form 25-hydroxy
cholecalciferol and second in the proximal tubules of the
kidney to form 1,25- dihydroxy cholecalciferol which is the
most physiologically active form of the vit-D i.e. calcitriol.

18. Dietary sources: Halibut liver oil (richest source), codfish
liver oil, other animals liver oil and synthesis in body as
explained above.
Physiological functions:
• Vitamin-D increases absorption of calcium and phosphates
from GIT and tubular reabsorption from renal tubules.
• It increases both serum calcium and calcitonin levels.
• It increases the bone mineralization and thus bone-mineral-
density (BMD) (deficiency leads to rickets in children and
osteomalacia in adults).

19. Deficiency Symptoms: Deficiency may occur in cases of
malnutrition, poor Sun exposure, intestinal malabsorption ,
chronic liver disease and chronic renal failure cases.
Manifestations may be in the form of:
• Rickets in children which may present in the form of
various bony deformities such as bow legs, bossing of
skull, chest deformities etc.
• Osteomalacia in adults which may present in the form
bone tenderness and decreased bone mineral density
(BMD) and predisposition to fractures.

20. • Recommended dietary allowance (RDA):
• Prophylactic dose is 400 IU/day and
• Therapeutic dose of nutritional vit D deficiency is 3000–
4000 IU/day.
• This is given to prevent and treat rickets in children and
Osteomalacia in adults.
• 300,000–600,000 IU can be given orally or i.m. once in 2–6
months.
• Recommended Daily Allowance if Sun exposure is adequate:
• Children: 5µgm/day,
• Adult: 2.5µgm/day,
• Pregnant/Lactating women: 10µgm/day
*1 μg of cholecalciferol = 40 IU of vit D.

21. Hypervitaminosis-D
• It can occur due to chronic intake of large doses
approximately 50,000 IU/day.
• Manifestations are hypercalcaemia, weakness, fatigue,
vomiting, diarrhoea, sluggishness, polyuria, albuminuria,
ectopic Ca2+ deposition in soft tissues, blood vessels,
parenchymal organs(calcinosis), renal stones or
nephrocalcinosis, hypertension, growth retardation in
children.

22. Vitamin D preparations: Supplementation is required in
many cases. A few preparation of Vit-D are as follows:
• Calciferol (Ergocalciferol, vit D2) : Filled in gelatin
capsules 25,000 and 50,000 IU caps.
• Cholecalciferol (vit D3) : As granules for oral ingestion and
oily solution for i.m. injection.
• Calcitriol : 0.25–1 μg orally daily or on alternate days
• Alfacalcidol : It is 1 α-OH D3—a prodrug that is rapidly
hydroxylated in the liver to the active form of vit D i.e. 1,25
(OH)2 D3 or calcitriol. Available in cap. form.
• Calcipotriol is a preparation for local use and useful in the
treatment of psoriasis.

23. Vitamin-E
• There are a number of tocopherols, of which α-tocopherol
has the most potent vit-E activity. It is also the most
abundant form of vit E.
• Dietary sources Wheat germ oil is the richest source,
others are cereals, nuts, spinach and egg yolk.

24. Physiological functions
• It is the most powerful antioxidant.
• It protects the unsaturated lipids in cell membranes from
free radical oxidation damage.
• It plays an important role in preventing the risk of
myocardial infarction, Alzheimer disease etc.
• It has a lipotropic action.
• It stabilizes RBC membrane and also enhances the use of
Vit-A.

25. Deficiency Symptoms: Deficiency of this vitamin may lead
to heamolytic anaemia, retinopathy, skeleton myopathy and
peripheral neuropathy with spinocerebellar degeneration.
Recommended dietary allowance (RDA)
• The estimated daily requirement of vit. E is 10 mg.
*1 mg of α-tocopherol= 1.49 IU of vit E.

26. Some conditions where Vit-E is useful are:
• G-6-PD deficiency: 100 mg/day
• In Retrolental fibroplasia, in premature infants exposed to high
oxygen concentrations can be reduced by 100 mg/kg/day oral
vitamin E.
• Acanthocytosis: 100 mg /week i.m.
• Fibrocystic breast disease, nocturnal muscle cramps and
intermittent claudications: 400–600 mg/day.
Hypervitaminosis-E
• No toxicity has been reported even with large doses of vit-E for
long periods.
• Some side effects are abdominal cramps, loose motions and
lethargy.

27. Vitamin-K
• Vitamin K (Koagulation vitamin) is essential for the
coagulation process.
• It is not directly involved in the clotting process but
required for the synthesis of four clotting factors in the
liver cell: Factor II,VII,IX and X.

28. • It occurs naturally in two forms:
• Phylloquinone (K1) from plant source and
• Menaquinone (K2) which is synthesized by colonic
bacteria (E. coli) in the colon.
• K3 is the synthetic form and is available as Fat-soluble
forms (Menadione, Acetomenaphthone) and water-
soluble forms (Menadione sod. Bisulfate and
Menadione sod. Diphosphate).

29. • Dietary sources: Green leafy vegetables such as
cabbage, spinach and liver, cheese, cereals, nuts, and
egg yolk etc. Wheat germ oil is the richest source.
Physiological functions:
• Vit-K is essential for formation of clotting factor-II, VII,
IX, X, protein-C & S.

30. Deficiency Symptoms
• Vit-K is only temporarily concentrated in liver and this
store can be exhausted within one week.
• The deficiency of vit-K occurs due to liver disease,
obstructive jaundice, malabsorption, long-term
antimicrobial therapy which alters intestinal flora.
• The most important manifestation is bleeding tendency
due to lowering of the levels of prothrombin and other
clotting factors in blood.
• Haematuria is usually first to occur;
• sites of bleeding are gastrointestinal tract, nose and under
the skin where it presents in the form of haemorrhagic
spots.

31. Recommended dietary allowance (RDA)
• Normal adult requirement is 50–100 μg/day.
• As it can be synthesized in the colon, even 3–10 μg/day
may be sufficient.
Some conditions where Vit-K is useful are:
• For prevention of haemorrhagic disease of the newborn: All
newborns specially premature infants have low levels of
prothrombin and other clotting factors.
• Vit K 1 mg i.m. soon after birth has been recommended
routinely.
• Alternatively, 5–10 mg i.m. to the mother 4–12 hours before
delivery can be given.

32. • Menadione (K3) should not be used for this purpose as
patients with G-6-PD deficiency and neonates are
especially susceptible. In the newborn menadione or its
salts can precipitate kernicterus.
• As an antidote in overdose of oral anticoagulants.
• In patients suffering from liver disease (cirrhosis, viral
hepatitis) .
• Patients on prolonged antimicrobial therapy.

33. • Patients with obstructive jaundice or malabsorption
syndromes (sprue, regional ileitis, steatorrhoea, etc). The
therapy given is Vit-K 10 mg i.m./day, or orally along with
bile salts for better absorption.
Hypervitaminosis-K
• It has not been reported.
• Only severe allergic or anaphylactoid reactions can
occur with iv injection of vit-K formulations.

34. WATER-SOLUBLE
VITAMINS

35. B complex group of vitamins
• The vitamins of this group all generally found together in
the food; hence are collectively termed as vitamin B-
complex.
• Most of these are found in both vegetarian and non-
vegetarian sources except vit-B12, which is not found in
vegetable sources, but is found only in various non-
vegetarian sources.
• The B-complex vitamins have been divided conventionally
into three subgroups according to the major functions in
which they are involved.

36. These are:
• Energy forming B-complex vitamins: Vitamin- B1, B2, B3,
B5, B6, B7 (Biotin)
• Hematopoietic B-complex vitamins: Folic acid (Vitamin-
B9), B12
• Non B complex group: Vit-C or ascorbic acid

37. Thiamine or Vitamin-B1 or Aneurine
Dietary sources: Cereals, pulses, nuts, green vegetables,
yeasts, egg and meat.
It is found in the outer layers of the cereals and is heat labile.
Physiological functions
• Its active form thiamine pyrophosphate acts as a
coenzyme in the carbohydrate metabolism.
• It also plays some role in nerve conduction.

38. Deficiency Symptoms
• Deficiency is mainly dietary in nature.
• In addition, raw fish, shellfish, coffee and tea inhibit the
absorption of vitamin-B1.
• Some common manifestations are:
• Beriberi (acute manifestation of B1 deficiency)
Dry Beri-Beri Wet Beri-Beri
 Mostly involves peripheral nervous
system.
 The common signs and symptoms
are: peripheral neuropathy, muscles
atrophy, muscles weakness, wrist &
foot drop.
 Mostly involves cardiovascular
system.
 The common signs and symptoms
are: tachycardia, oedema,
cardiomegaly, high output cardiac
failure.

39. • The treatment involves i.v./i.m. injection of vitamin-B1
given in a dose of 2-10 mg OD, till the symptomatic
improvement occurs. Then treatment is given orally.
• Infantile beriberi: In this condition, newborn of vitamin-B1
deficient mother presents with signs and symptoms of
Beri-Beri.
• To manage this condition, prophylactically 2-10mg/day
Vitamin-B1 is supplemented to pregnant mother or infants.

40. • Wernick’s encephalopathy: It is most commonly seen in
severe alcoholic individuals. Patient presents with global
confusion, ophthalmoplegia and cerebral ataxia and
these features combined with psychosis are called
Koraskoff’s psychosis. (confabulation)
• To prevent this condition thiamine is given in a dose of 100
mg/day intravenously.
Transketolase (product of HMP shunt) test is done to detect vitamin-B1 deficiency.

41. Recommended dietary allowance (RDA): 1-2 mg/ day.
Therapeutic uses:
• Prophylactically: 2–10 mg daily is given in infants, pregnant
women, chronic diarrhoea and patients on parenteral
alimentation.
• Beriberi—100 mg/day i.m. or i.v. till symptoms regress. After it,
maintenance doses are given orally.
• Acute alcoholic intoxication: Thiamine 100 mg is added to each
vac of glucose solution infused. In Korsakoff’s psychosis, 100
mg/day is given parenterally.
• In neurological disorders.
Adverse effects
• Thiamine is nontoxic. Sometimes, hypersensitivity reactions can
occur on parenteral injection.

42. Riboflavin or Vitamin-B2
• Dietary sources: Dairy milk products, liver, meats, egg,
cereals, pulses, yeast, green vegetables and sprouts etc.
• Physiological functions: Its active form acts as
coenzyme in the oxidation-reduction reactions and
carbohydrate metabolism.

43. Deficiency Symptoms
• Ariboflavinosis: The deficiency of vitamin-B2 usually
presents with angular stomatitis, cheilosis,
seborrheic dermatitis and geographical ulcer on
tongue.
• For therapeutic purpose in Ariboflavinosis:
Riboflavin is given in a dose of 2–20 mg/day oral or
parenteral till the symptoms subside.
Recommended dietary allowance (RDA): 1-2 mg/
day.

44. Niacin or Vitamin-B3
• Dietary sources: Liver, meats, egg, fish,cereals,
wholegrains, , nuts etc.
• Physiological functions: Nicotinic acid is readily
converted to its amide which is a component of the
coenzyme Nicotinamide-adenine-dinucleotide (NAD) and
its phosphate form (NADP) involved in oxidation-reduction
reactions involved in cellular respiration, glycolysis and
fatty acid oxidation.
• Nicotinic acid is also a lipid-lowering agent.

45. Deficiency Symptoms
• Pellagra: A deficiency of Niacin may present with 4 Ds:
diarrhoea, dermatitis, dementia and death. Along with these
features, anaemia and hypoproteinaemia are also seen.
These feature are commonly seen in malnourished and
alcoholic individuals .
• To treat this condition, niacin is given twice daily in a dose of
200 to 500 mg orally.
• Hartnup’s disease: Another deficiency of Niacin,
particularly by tryptophan, which is a precursor of niacin
formation. Supplementation of niacin is curative.

46. • Recommended dietary allowance (RDA): 15-20 mg/
day.
• Therapeutic uses:
• Pellagra treatment: Niacin is given twice daily in a dose
of 200 to 500 mg orally.
• Dyslipidemia: Nicotinic acid also used for managing
dyslipidemia in a dose of 250 mg BD to 2.0gm/day in
sustained release form or three divided doses.
• Hartnup’s disease: in which tryptophan transport is
impaired, need niacin supplementation.

47. Pantothenic acid or Vitamin-B5
• Dietary sources: Liver, meats, egg yolk, fish, cereals,
wholegrain, nuts, vegetables, etc.
• Physiological functions: It is a component of coenzyme-
A which functions in carbohydrate, fat, steroid and
porphyrin metabolism.

48. • Recommended dietary allowance (RDA): 2-7 mg/day.
Therapeutic uses:
• 1. For the treatment of burning foot syndrome, 50-100 mg
/day is given.
• 2. Sometimes it is used to treat postoperative paralytic
ileus.

49. Deficiency Symptoms:
• It has been thought to be one of the causing factor of
leg cramps, paraesthesia and flatulence.
• Burning Foot Syndrome (Nutritional megalalia) may
occur due to deficiency of pantothenic acid and seen in
individuals expose to heavy antibiotic therapy or colonic
resection or severe malnutrition.

50. Pyridoxine or Vitamin-B6
Pyridoxine, Pyriodoxal and Pyridoxamine are related
naturally occurring pyridine compounds that have vit B6
activity and are vitamers of vit B6.
• Dietary sources: Widely distributed in the food products
of plant and animal origin such as vegetables, soybean,
wholegrain, eggs, liver, meat, etc.

51. Physiological functions:
• Pyridoxine is converted to its coenzyme form i.e.
pyridoxal phosphate.
• Pyridoxal phosphate dependent enzymes
(transaminases, hydroxylases and decarboxylases) are
involved in synthesis of nonessential amino acids,
GABA and aminolevulinic acid (first step in the
synthesis of haeme).

52. Deficiency Symptoms:
• Peripheral neuropathy: Presents with tingling sensations
of lower limbs. Isoniazid and OCPs produce a pyridoxine
deficiency state.
• Sideroblastic anaemia: Can be treated by administration of
50–200 mg/day pyridoxine phosphate.
• Seborrheic dermatitis, glossitis, growth retardation,
premenstrual tension, mental confusion, lowered seizure
threshold and convulsions.
Recommended dietary allowance (RDA): 0.8 mg/1000Kcal (2 mg/
day).

53. Therapeutic uses:
• Prophylactically in alcoholics, infants and patients with
deficiency of other B complex vitamins: 2–5 mg daily.
• To prevent and treat isoniazid, hydralazine and
cycloserine induced neurological disturbances: 10–100
mg/day.
• To treat mental symptoms in women on oral
contraceptives: 50 mg daily.
• Pyridoxine responsive anaemia may be benefited by large
doses of pyridoxine: 50–200 mg/day.

54. Biotin or Vitamin-B7 or vitamin H
• Biotin is a sulfur containing organic acid found in many
food items.
• Some intestinal bacteria synthesize biotin which is also
absorbed.
• Its deficiency can be caused by eating raw egg white for
months to years.
• Egg white contains a protein named “Avidin” which binds
biotin strongly and prevents its absorption.
• Dietary sources: Liver, egg yolk, meat, nuts are the other
source.

55. Physiological functions:
• Biotin is a coenzyme for five carboxylases in the body and is
essential for amino acid catabolism, gluconeogenesis and
fatty acid metabolism.
• It is also essential for gene stability because it is covalently
attached to histones.
• Deficiency Symptoms: Deficiency can occur due to regular raw
egg white intake, colonic resection or severe malnutrition or
heavy exposure to antibiotics.
• Symptoms are : anorexia, glossitis, seborrheic dermatitis,
alopecia, fatigue and muscular pain.
Recommended dietary allowance (RDA): 0.2 mg /day.
• Therapeutic dose in case of deficiency symptoms is 10-20 mg
/day.

56. Folic acid or Vitamin-B9
• In 1941, Mitchell isolated an antianaemia principle from
spinach and called it ‘folic acid’ (from leaf).
• Folic acid is present in the food as polyglutamates.
• Each folic acid molecule may have 2-8 molecules of
glutamic acid.
Dietary sources: Green leafy vegetables(spinach), Liver,
egg, meat, milk. It is also synthesized by gut flora, but this is
largely unavailable for absorption.

57. Physiological functions: Folic acid is inactive as such and is reduced to the coenzyme form
in two steps:
• FA is converted to DHFA by by folate reductase (FRase) and then to THFA by
dihydrofolate reductase (DHFRase).
• THFA mediates a number of one carbon transfer reactions which are essential in
the synthesis of purines and pyrimidines.
• These purines and pyrimidines are essential in DNA synthesis.

58. Deficiency Symptoms: These can occur due to dietary
deficiency, malabsorption syndrome, excessive demand, liver
diseases or drug induced.
The manifestations are:
• Megaloblastic anaemia
• Neural tube defects: Neural tube defects, including spina
bifida in the offspring, due to maternal folate deficiency.
This can be prevented by administration of folic acid
started 3 month before conception till 1st trimester followed
by iron with calcium.
• Epithelial damage: Glossitis, enteritis, diarrhoea,
steatorrhoea.etc.
• General debility, weight loss, sterility.

59. • Recommended dietary allowance (RDA): Dose: 2 to 5
mg/day, prophylactic 0.5 mg/day.
Therapeutic uses:
• Megaloblastic anaemias, Nutritional folate deficiency,
• Increased demand: pregnancy, lactation, infancy, during
treatment of severe iron deficiency anaemia, haemolytic
anaemias.
• Pernicious anaemia.
• Malabsorption syndromes: Tropical sprue,coeliac disease,
idiopathic steatorrhoea, etc.
• Antiepileptic therapy: patients on prolonged
phenytoin/phenobarbitone therapy
• Prophylactic of folate deficiency: during pregnancy to
prevent neural tube defects in foetus.

60. Vitamin-B12
• Cyanocobalamin and hydroxocobalamin are complex cobalt
containing compounds present in the diet and referred to as vit-B12.
Dietary sources
• Richest source is liver, which contains large deposite of vitamin-
B12 and that is sufficient for 2-5 years. Other sources are kidney,
sea fish, egg yolk, meat, cheese.
• The only vegetable source is legumes (pulses) which get it from
microorganisms harboured in their root nodules. Vit B12 is
synthesized by the colonic microflora, but this is not available for
absorption in man. The commercial source is Streptomyces
griseus.
• Animal food product contain higher amount of Cynocobalamine
than plant products.

61. Physiological functions:
• Vit-B12 is intricately linked with folate metabolism.
• The active coenzyme forms of B12 generated in the body are
deoxy-adenosyl-cobalamin (DAB12) and methyl-cobalamin
(methyl B12).
• It links the carbohydrate and lipid metabolisms.
• It is needed in the synthesis of phospholipids and myelin
sheath .
• Vit-B12 is essential for cell growth and multiplication.
• Deficiency Symptoms: Vitamin-B12 deficiency may occur due
to strict vegetarian diet, pernicious anaemia, severe
malabsorption, surgical resection of terminal ileum or stomach.

62. Deficiencies of vitamin-B12 manifest as:
• Megaloblastic anaemia.
• Subacute combined degeneration of spinal cord (SACD).
• Peripheral neuritis which usually presents with loss of fine
touch, vibration and proprioception, paresthesias and
depressed stretch reflexes. If these features are present with
psychosis, it is called Megaloblastic madness. To prevent this
condition administer 1000µgm vitamin-B12 weekly for 8
weeks.
• Glossitis, GI disturbances and damage to epithelial structures.
Recommended dietary allowance (RDA): Adult- 1-3 µgm/day,
pregnancy and lactation 3–5 μg/day.

63. Therapeutic uses
• Treatment of vit-B12 deficiency: vit B12 is used alongwith
1–5 mg of oral folic acid and an iron preparation to get best
results.
• Prophylaxis: when there are definite predisposing factors for
development of deficiency.
• Tobacco amblyopia: hydroxocobalamin provides some
benefit by trapping cyanide derived from tobacco to form
cyanocobalamin.
• Mega doses of vit B12 have been used in neuropathies,
psychiatric disorders, cutaneous sarcoid and as a general
tonic to allay fatigue, improve growth. The value of these uses
is questionable.
Adverse effects: Even large doses of vit-B12 are quite safe.
Allergic reactions have occurred on injection, probably due to
contaminants. It should never be used by IV route.

64. Vitamin- C
• Ascorbic acid is an organic acid with structural similarity to
glucose. It is a potent reducing agent and l-form is
biologically active.
• Vitamin-C is sensitive to heat.
• Dietary sources: Citrus fruits (lemons, oranges), black
currants, crane berry, ley berry, guava, tomato, leafy
vegetables, sprouts, mango and green chilies.
• Breast milk contain more vit-C than cow’s milk.
• Indian gooseberry (Amla) is the richest source of
vitamin- C.

65. Physiological functions:
• Vit-C plays important role in many oxidative and other
metabolic reactions.
• It is essential for the formation and stabilization of collagen.
Therefore, it plays essential role in tissue repair and
formation of cartilage, bone and teeth.
• It acts as an antioxidant, improves immunity and prevents
cataract formation also.
• It plays an important role in absorption of iron and
conversion of folic acid to folinic acid; therefore helps in RBC
production [erythropoiesis].
• It plays an important role in biosynthesis of adrenal steroids,
catecholamines, oxytocin, vasopressin and bile acid.

66. • Deficiency Symptoms: Scurvy [swollen and bleeding
gums], Delayed wound healing, anemia, growth
retardation, brittle bones, etc.
• Recommended dietary allowance (RDA): 40-60mg/day.

67. Therapeutic uses:
• Prophylactic dose: In deficiency susceptible individuals] is 50-
100 mg daily.
• Therapeutic dose in scurvy treatment is 500-1500 mg/day.
• To acidify urine in UTI treatment: 1 gm TDS.
• Anaemia: To enhance the iron absorption [500 mg BD; along
with iron tablets].
• To improve immunity and wound & fracture healing after
surgery, injury, etc given in a dose of 500 mg daily along with
Zinc.
Adverse effects: Renal oxalate stone formation can occur when
higher doses are taken for longer durations.