1. VITAMINS
HARSHIT SHETH

2. Nutrients
Carbohydrates
Fats
Proteins
Vitamins
Minerals
Water

3. Vitamins
 The word "vitamin" comes from vita, the
Latin for "life“
 Everybody must eat a certain amount of
vitamins to stay healthy
 Vitamins are chemicals found in very
small amounts in many different foods.
Tiny quantities are enough for the needs
of the body
 If people live on a very limited range of
foods they may not get their proper share
of vitamins

4. Classification of
Vitamins Vitamins, of which there
are 14, are classified
into two main groups:
Water soluble and Fat
soluble
 Fat soluble – stored in
bodies fat tissue
 A, D, E & K
 Water soluble – not
stored in the body
 B vitamins, folic acid &
vitamin C

5. CLASSIFICATION
OF VITAMINS:
Vitamin B7
Vitamin B5

10. Vitamin C - Ascorbic
Acid
 Structure
 Metabolism
 oxidation/reduction
 dehydroascorbic acid
 dehydroascorbate
reductase
 glutathione (GSH)
 glutamate-cysteine-
glycine

11. Vitamin-C(Ascorbic acid)
 Vitamin C - helps to
maintain skin integrity,
absorb iron from the gut
and heal wounds, and is
important in immune
functions
Dietary sources:
 Vitamin C is found in citrus
fruit and juices, tomatoes,
spinach, potatoes, berries,
green and red peppers,
and broccoli

12. Functions of
Vitamin C
Enhances absorption of
iron
reduces iron to more
absorbable ferrous form
chelates with ferrous ion to
make it more soluble

13. Functions of
Vitamin C
Hydroxylation of proline and
lysine
post-translational reaction of
procollagen
hydroxylated collagen can be cross-
linked to triple helix collagen
Scurvy - weak collagen

14. Functions of
Vitamin C
Hydroxylation Reactions
Involves O2 and metal coenzyme
 (ferrous, cuprous)
Carnitine synthesis
Tyrosine synthesis & catabolism

15. Functions of
Vitamin C
Hydroxylation Reactions
Synthesis of Neurotransmitters
Dopamine
Norepinephrine
Serotonin
Bile acid synthesis

16. Functions of
Vitamin C
Antioxidant Activity
Reacts and removes active
oxygen species
Pro-oxidant Activity
Reduces metals to their pro-
oxidant forms

17. Scurvy
Bleeding gums
petechiae
easy bruising
impaired wound healing and
bone repair
joint pain
anemia

18. RDA for Vitamin C
10 mg/day prevents scurvy
historic RDA’s 45-70 mg (60mg
in 1989), 75mg in 2000
prevention of scurvy vs
antioxidant effect with
supplements?

19. Toxicity of Vitamin C
 UL adults: 2000mg/d
 Osmotic diarrhea
 Oxalate kidney stones
 Decreases uric acid reabsorption
resulting in increased risk of gout
 Affects diagnostic tests in feces and
gout
 fecal blood
 urinary glucose

20. VITAMIN B-COMPLEX

21. Thiamin- B1
Structure
pyrimidine ring
thiazole ring
methyl bridge

22. Thiamin : vitamin form
Thiamin pyrophosphate: coenzyme form
Pyrimidine ring Thiazole ring

23. Dietary sources: cereals, pulses, oil
seeds, nuts and yeast are goods
sources.
 In animal food like pork, liver, heart,
kidney, milk etc.
 RECOMMENDED DIETARY
ALLOWANCE: Adults: 1-1.5 mg/day.
Children: 0.7-1.2 mg/day.

24. Biochemical
Functions of B-1
 Oxidative Decarboxyation Reactions
 Pyruvate Dehydrogenase
 Pyr+CoA+NAD --> AcCoA+CO2 +NADH
 a-keto-glutarate dehydrogenase
 aKG+CoA+NAD-->SuccCoA + CO2+NADH
 important in CHO/energy metabolism

25. Biochemical
Functions of B-1
Transketolation
HMP pathway
Peripheral Nerve Function
TPP or TPPP
non-cofactor function
mechanism?

26. Thiamin
Deficiency
Beri-Beri
anorexia, fatigue, depression
effects on
cardiovascular system
nervous system

27. Infantile Beri-Beri
first 6 months
breast milk deficient in B-1
mother w/o symptoms
rapid onset
cyanosis, tachycardia, labored
breathing
heart failure and death

28. Wet Beri Beri
 symptoms similar to congestive
heart failure
 Pitting edema - trunk, limbs, face
 labored breathing, tachycardia
 rapid deterioration
 fatal cirulatory collapse
 responds rapidly to B-1
supplements

29. Dry Beri-Beri
no edema
progressive wasting
numbing and
weakening of
extremities
chronic infections

32. Assessment of
Thiamin Status
Urinary thiamin excretion
Blood or serum thiamin
concentration
[pyr + lac] in blood
erythrocyte transketolase
activity
stimulation with B-1

33. RIBOFLAVIN-B2
 Structure: 6,7 dimethyl isoalloxazine +
D-ribitol. Attached by nitrogen atom.

38. Niacin
Structure
Nicotinic Acid = Niacin
Nicotinamide =
Niacinamide

39. Cofactor Forms of
Niacin
 Nicotinamide Adenine Dinucleotide
 NAD
 nicotinamide-ribose-PP-ribose-adenine
 Nicotinamide Adenine Dinucleotide
Phosphate
 NADP
 nicotinamide-ribose-PP-(ribose-P)-adenine

40. Nicotinic Acid (Plant form)
Nicotinamide (animal form)
(reduced form)

41. Nicotinamide Adenine Dinucleotide
nicotinamide
adenine
If Phosphate here ->
NADP

44. Biochemical
Functions of B-3
Oxidation-Reduction
Reactions (NAD/NADH
 Dehydrogenases
 Electron Transport System
 Involved in energy production

45. Biochemical
Functions of B-3
Synthetic Pathways (NADPH)
 FA synthesis
 Cholesterol synthesis
 NEAA synthesis
 Purine & Pyrimidine synthesis

46. Deficiency of B-3
Pellegra
Dermatitis
 scaly dermatitis, sun exposed
Dementia
 confused, disoriented
Diarrhea
 irritation/inflammation of mucous membranes

49. Assessment of B-3
Status
Urinary excretion of niacin
metabolites
N-methyl nicotinamide
2-pyridone

50. Vitamin B-12
Structure
cobalamine
methyl
cobalamine
 transport and
coenzyme form
adenosyl
cobalamine
 storage and
coenzyme form

51. Dietary Sources
Animal products
 including milk and eggs
GI microorganisms
Vegan sources
 N-fixing legumes
 fortified grains
 vitamin supplements

52. Digestion &
Absorption of B12
Intrinsic Factor
 gastric glycoprotein
 binds with B12 in small intestine
 IF-B12 complex binds to B12receptor in
ileum for absorption
 B12 absorption requires functioning
stomach, pancreas, and ileum

53. Causes of B-12
Deficiency
Inadequate intake - rare
DRI adults 2.4 ug/d
Usual intake 7-30 ug/d
Malabsorption of B-12
IF deficiency
other GI tract problems

54. Functions of B12
Homocysteine to Methionine
 methionine synthetase
requires 5-methyl THF
deficiency of B12 results in “methyl-
trap” of folate
 results in megaloblastic anemia
 synergistic effect of B12 and folate

55. Functions of B12
Mutases
methyl malonyl CoA mutase
proprionyl-CoA ->->succinyl-CoA
accumulation of methyl-malonate
may inhibit AcetylCoA carboxylase

56. B-12 Deficiency
 Pernicious anemia
 megaloblastic anemia
 Methyl-folate trap
 Delayed or failure of normal cell division
due to impaired DNA synthesis
 neuropathy
 defective myelination
 progressive peripheral weakening
 unresponsive to folate
 upper limit to folate
supplementation/enrichment

57. Folic Acid / Folacin
Structure
 pteridine ring - PABA - glutamate
Stability
very sensitive to heat
easily oxidized
leached

58. RDA : 200 microgram/day.
During pregnance:400 microgram/day

59. Folate Functions
Single carbon metabolism

60. Folate
Functions
 Interconversion of serine and glycine
 ser + THF <---> gly + 5,10-Me-THF
 Degradation of histidine
 his->->->formiminoglutamate(FIGLU)
 FIGLU+THF -> glu + 5-forminino-THF
 histidine load test
 Functional test for folate status

61. Folate Functions
Purine and Pyrimidine
Synthesis
 dUMP + 5,10-Me-THF -> dTMP + THF
Methionine Synthesis
 homocysteine + 5-Me-THF -> MET +
THF
 MET as a methyl donor for choline
synthesis

62. Folate Deficiency
Megaloblastic Anemia
 decreased DNA synthesis
 failure of bone marrow cells to divide
 normal protein synthesis
 results in large immature RBC’s
 contrast with microcytic hypochromic
anemia

63. Folate Deficiency
Homocysteine
 Coronary Heart Disease risk factor ?
 genetic homocystinuria - premature
CHD
 hi [homocys] related to hi CHD risk
 lo [folate, B-12, B-6] related to hi CHD
risk
 lo intake of B-vit related to hi CHD risk

64. Folate and CHD
Nurse’s Health Study (JAMA 1998)
80,000 nurses, 14 yr follow-up
Relative Risk - highest vs lowest
quintile
RR = 0.69 for folate
RR = 0.67 for B-6
RR = 0.55 for folate + B-6

65. Folate and Neural
Tube Defects
Defects in formation of neural
tube (brain & spinal cord)
First two months gestation
Anencephaly
absence of cerebral hemispheres

66. Folate and Neural
Tube Defects
Spina bifida
 defective closure of vertebral column
 spinal cord protrusion from spinal
column results in damage to spinal
cord
 lower limb and hip paralysis
 rectal and bladder problems

80. Names and Roles
Vitamins
A retinol phototransduction
D cholecalciferol bone remodeling
E tocopherols antioxidant
K phytylmenaquinone
multiprenylmenaquinone
coagulation
bone remodeling
B1 thiamine carbohydrate metabolism
B2 riboflavin redox, respiration
B3
niacin redox
B6
pyridoxine
pyridoxamine
pyridoxal
aa metabolism
glycogenolysis
B5 Pantothenic acid tca, fa and cholesterol
B7 Biotin gluconeogenesis, tca, fa, aa
B12 cobalamin 1C&H metabolism
B9 Folic acid 1C metabolism
C ascorbic acid hydroxylation

81. Deficiencies and Sources
Vitamins
A - night blindness
preformed: liver, egg yolk, butter, milk
β-carotene: dark green and yellow veggies
D - ricketts, osteomalacia milk, fortified food, fish oils, egg
yolks, liver
E - neurologic?, hemolytic anemia veggie oils, nuts
K - bleeding disorders green leafy veggies, fruits, dairy products, veggie
oils, cereals, meats
B1 - beri-beri seeds, nuts, wheatgerms, legumes, lean meat
B2 - pellagra meats, nuts, legumes
B3 - pellagra meats, nuts, legumes
B6 - neurologic disease yeast, liver, wheatgerm, nuts, beans,
bananas
B7 - widespread injury corn, soy, egg yolk, liver, kidney,
tomatoes
B12 - pernicious anemia liver, kidney, egg, cheese
B9 - anemia yeast, liver, leafy veggies
C - scurvy citrus and soft fruits
B5 - none known yeast, grains, egg yolk, liver

82.  THANKS