This document provides information about Vitamin A, including its key features, functions, deficiency, toxicity, and sources. It discusses how Vitamin A is necessary for vision, gene transcription, immune function, embryonic development, and other processes. Deficiency can cause night blindness and keratomalacia, while toxicity may result in headaches, vomiting, and other issues. Good sources include liver, egg yolks, dairy products, carrots, and other orange and dark green vegetables.

1. O n e S t e p To w a r d s S h a r i n g K n o w l e d g e … .
E x a m i n a t i o n P e r s p e c t i v e
B y
M a n o j P r a j a p a t i
M . S . ( P h a r m ) N I P E R
S A S N a g a r

2. Drug Toxicity and Antidotes

7. Vitamins

8. The detailed study of Vitamins begun with
discovery of vitamin B1 in 1912 in rice bran by
Polish biochemist Casimir Funk.
Funk Proposed the name “VITAMIN” (vital
amines), however is was clarified by that time
that not all vitamins are amines.

9. Classification
According to their solubility characteristics vitamins can be divided in
two categories; i.e. Lipid soluble and water soluble vitamins
Lipid soluble water soluble
A, D, E and K B and C
 hydrophobic compounds, absorbed
efficiently with lipids,
 transport in the blood in lipoproteins or
attached to specific binding proteins,
 more likely to accumulate in the body,
 more likely to lead to hypervitaminosis
 Function: mainly as enzyme cofactors,
 hydrophilic compounds dissolve easily in
water,
 not readily stored, excreted from the body,
 their consistent daily intake is important.
 Many types of water-soluble vitamins are
synthesized by bacteria

10.  Vitamins are essential substances that our bodies need to
develop and function normally.
 An organic compound required as a nutrient in tiny amounts by
an organisms.
 It cannot be synthesized in sufficient quantities by an organism,
and must be obtained from the diet.
 Vitamins performs diverse biological functions:
Hormone-like functions as regulators of mineral metabolism (vit. D),
Regulators of cell and tissue growth and differentiation ( vit. A)
Antioxidants ( vit. E, C)
Enzyme cofactors

12. Vitamin A – Key Features
Exam Prospective
☺ Biologically active forms - retinoids: retinol, retinal, retinoid acid.
☺ Major vit. A precursors (provitamins) → plants carotenoids.
☺ Vit. A is necessary to form rhodopsin (in rodes, night vision) and iodopsins (photopsins,
in cones – color vision) - visual pigment.
☺ Retinaldehyde is a prosthetic group of light-sensitive opsin protein.
☺ Absorption of light → conformation changes of opsin → photorhodopsin.
☺ Deficiency of vit. A leads to night blindness.
☺ Vitamin A is an important antioxidant.
☺ Keratomalacia is disorder of Vitamin A deficiency
☺ Retinoic acid regulates the transcription of genes - acts through nuclear receptors
☺ Retinoic acid is necessary for the function and maintenance of epithelial tissues.

13. Vitamin A Deficiency
☺ Ttransformation of respiratory epithelium – loss of protective airway function
(antibacterial properties) → bronchitis.
☺ Conversion of the urinary tract epithelium → higher frequency of urinary stone formation
☺ Immunosuppression
☺ Impairment of reproductive function (both in men and women).
Vitamin A - toxicity
☺ Acute symptoms - headache, vomiting, impaired consciousness.
☺ Chronic intoxication – weight loss, vomiting, pain in joints, muscles, blurred vision, hair
loss, excessive bone growth.
☺ Both vit. A excess and deficiency in pregnancy are teratogenic – retinoic acid is gene
regulator during early foetal development
☺ Carotenoids are non toxic - accumulation in tissues rich in lipids (the skin of babies
overdosed with carrot juice may be orange).

14. Metabolic functions of vitamin A
☺Vision
☺Gene transcription
☺Immune function
☺Embryonic development and
reproduction
☺Bone metabolism
☺Haematopoieis
☺Skin health
☺Antioxidant activity
Sources of vitamin A
cod liver oil
meat
egg
milk
dairy products
 carrot
 broccoli
 spinach
 papaya
 apricots

15. Vitamin B
Vitamin B1: Thiamin
 Part of coenzyme thiamin pyrophosphate (TPP)
 Play key role in Energy metabolism
 Used in the Conversion of pyruvate to acetyl CoA in glucose metabolism
 Participates in citric acid cycle in mitochondria
 Essential for nerve activity and muscle activity
Deficiency
–Malnourished and alcoholics
– Wernicke–Korsakoff syndrome
–Beriberi
Dry – nervous system
Wet – cardiovascular system
 Prolonged cooking destroys thiamin
 Leaches into water when boiling or blanching foods

16. Found in: meat, legumes, and whole, fortified, or enriched grain products, cereals and
breads. Yeast and wheat germ.

17. Vitamin B2: Riboflavin
Functions:
 Electron transport chain (see below) or as intermediate electron carriers
 As a coenzyme for: xanthine oxidase, aldehyde oxidase, pyridoxine phosphate oxidase,
glutathione reductase
 Synthesis of folate
 Monoamine oxidase metabolism – neurotransmitters
 Prevention of cataracts
 Treatment of migraine headaches
 Serves as coenzyme in energy metabolism, Flavin mononucleotide , Flavin adenine dinucleotide
• Carries hydrogen atoms and their electrons to electron transport chain
• Each time it does this, 2 molecules of ATP are generated
Deficiency
– Inflammation of membranes
Destruction of riboflavin
– Ultraviolet light
– Irradiation
– Not destroyed by cooking

18. Found In: milk and milk products, eggs, meat and legumes

19. Vitamin B3: Niacin
 Two chemical structures
• Nicotinic acid
• Nicotinamide
Major form of niacin in blood
 Two coenzyme forms participate in metabolic reactions
Nicotinamide adenine dinucleotide (NAD)
- Carries hydrogen atoms and their electrons to electron transport chain
Deficiency
• Pellagra
• Symptoms: 3 Ds
• Diarrhea
• Dermatitis
• Dementia
Toxicity
 Naturally occurring: no harm
 Supplements or drugs
- “Niacin flush”
- Nausea, vomiting, liver damage, glucose intolerance
 Potential health benefits of large doses of nicotinic acid: may lower LDL
cholesterol

20. Sources:
•Fish (tuna and halibut), beef, chicken, turkey, pork (nicotinamide).
•Enriched cereals and breads, whole grains, seeds, and legumes (bound to carbs as
niacytin; bound to peptides as nyacinogen).
•Coffee and tea!!!
•Synthesized in liver from tryptophan

21. Vitamin B5: Pantothenic Acid
Functions:
• A part of coenzyme A
•Acetylates sugars, proteins, fatty acid metabolites
•Oxidative decarboxylation of pyruvate
•Synthesis of cholesterol, bile salts, ketones, fatty acids, steroid hormones
• A part of 4’-phosphopantetheine
•Prosthetic group for acyl carrier protein (ACP) in fatty acid synthesis
• Wound healing
• Cholesterol metabolism; pantethine
Excretion – primarily urine
Toxicity – rare; tingling hands and feet
Nutrient and Drug Interactions:
• Oral contraceptives containing both estrogen and progesterone

22. Sources: virtually all foods; high in meats, egg yolk, potatoes, mushrooms,
legumes and whole grain cereals, royal jelly from bees
Deficiency of this
vitamin results in
nausea, vomiting,
certain
gastrointestinal tract
disorders,
paresthesia,
inadequate growth,
anemia, fatty liver and
failure in gaining
weights.

23. Vitamin B6: pyridoxine,
pyridoxal, pyridoxamine and their phosphate derivatives
Functions:
 Coenzyme (>100 reactions) most in amino acid metabolism
•Transamination
•Decarboxylation
 Initial step in glycogen metabolism
•Glycogen phosphorylase
 Amino acid metabolism
 Urea metabolism
 Conversion of tryptophan to niacin or serotonin
 Synthesis of heme, nucleic acids, & lecithin
 Influences cognitive performance, hormone activity, and immune function

24. Deficiency: relatively rare
Symptoms include: sleepiness, fatigue, cheilosis, glossitis, stamatitis, and neurological
problems; alteration of magensium and calcium metabolism; impairs niacin synthesis;
inhibits homocysteine metabolism
Isoniazid (anti-tuberculosis med): B6 antagonist
Impacts amino acid metabolism
Toxicity: sensory and peripheral neuropathy (100 mg/day);
High doses used for hyperhomocysteinemia, carpal tunnel syndrome, premenstrual
syndrome, depression, muscular fatigue, and autism.

25. Sources: Pyridoxine in plant sources; pyridoxal phaophate and pyridoxamine phosphate
primarily in animal products
Overall found in meats, whole-grain products, vegies, bananas, and nuts, also fortified cereals;
processing influences availability

26. Vitamin B7: Biotin
 Coenzyme critical in citric acid cycle
Facilitates first step in cycle (entry point for acetyl-CoA
Participates in breakdown of fatty acids and amino acids
 Participates in gluconeogenesis and fatty acid synthesis
 Deficiency is very rare, no known toxicity
Widely distributed in foods, needed in small amounts (30 mcg/day)
Raw egg white consumption
Deficiency symptoms:
hair loss, rash, neurological impairment
•Lethargy, depression, hallucinations, muscle pain, parathesia, anorexia, nausea,
alopecia, dermatitis
•May occur during pregnancy
•May occur with excessive consumption of alcohol
•Is known as a teratogen in mammals

27. Sources: liver, soybeans, egg yolk, cereals, legumes, nuts; found combined to lysine
(biocytin) or other proteins; intestinal bacteria can synthesize biotin

28. Vitamin B9: Folic Acid
(folacin; folate; pteropolyglutamate)
 Secretion by liver into bile
 Synthetic form (folic acid) 1.7x more bioavailable than natural form (folate)
 Supplementation or careful monitoring of dietary folate adequacy recommended for all
women of childbearing age
 To get 400 mcg/d, at least 5 servings of fruits and vegetables recommended
Functions:
 Coenzyme – accepts one-carbon groups then donates them in synthetic reactions (histidine,
serine, glycine, methionine)
 Plays a role in reducing blood homosysteine levels

29.  Needs rise during pregnancy
- Closure of neural tube, from which brain and spinal cord develop, occurs during
first few weeks
- Low folate status in mother can cause brain and spinal cord disorders, and even
death of infant/fetus
Deficiency;
 Impairs cell division and protein synthesis
 Red blood cells and GI tract cells falter
 Anemia
 GI tract deterioration
 Primary deficiencies: due to inadequate intake or increased need
 Secondary deficiencies: drugs
Anti-cancer meds (folate antagonists)
Heavy use of aspirin or antacids
Oral contraceptives
Smoking

30. Toxicity
 Can occur from natural or supplemental/fortified sources
 Primary concern: can mask B12 deficiency, since early signs of B12 deficiency are
usually due to impaired folate activity
Sources: mushrooms, green leafy vegies, legumes, citrus fruits, and liver; raw foods have
more than cooked

31. Vitamin B12: Cynocobalamin
 Vitamin B12 and folate depend on each other for activation
 Very important for DNA synthesis, cell replication
 Individual roles of vitamin B12
Maintains myelin sheath, promotes normal growth of nerve cells
Involved in bone cell metabolism/activity
Deficiency
 Inadequate absorption or intake
Lack of hydrochloric acid or intrinsic factor
 Individuals at risk
Older adults: atrophic gastritis
Vegans
Those with anemia of folate deficiency
 Symptoms of vitamin B12 deficiency
Moderate: cognitive impairment
Severe: creeping paralysis

32. Deficiency; megaloblastic, macrocytic anemia;
 Symptoms include: pallor, fatigue, sortness of breath, palpitations, insomnia, tingling and
numbness in extremities, abnormal gait, loss of concentration, memory loss, and possibly
dementia.
 Anemia can be corrected with large doses of folate, but the neuropathies cannot.
 Associated with risk factors for coronary heart disease via homocysteine production
 Most deficiencies associated with:
 Malabsorption (long term vegetarians; vegetarian children and infants; changes in intrinsic
factor production;
 GI diseases such as sprue;
 Prolonged use of H blockers and proton pump inhibitors

33. Sources: all naturally occurring B12 is made by microorganisms; we get ours from animals
that have B12 from microorganisms
Meat, meat products, poultry, fish, shellfish, and eggs (yolk), milk and milk products, tobacco.

34. Vitamin C: Ascorbic Acid
o Naturally found in citrus fruits and many other vegetables
o It is an essential nutrient in human diet necessary to maintain connective tissue.
o Vitamin C cannot be produced or stored by humans and must be obtained through the diet.
Functions,
 It is critical for building collagen. Collage is the connective tissue protein which cements the
cells and tissues together.
 This vitamin helps in the formation of strong blood vessels.
 Vitamin C also helps in holding the teeth and bones firmly in their sockets.
 It plays an important role as an antioxidant, by regenerating oxidized vitamin E in the
membranes.
 It reduces the ferric ion (Fe3+) to ferrous (Fe2+) ion and thus helps in the absorption of iron.
 This vitamin is essential for rapid healing of wounds.
 Vitamin C helps fighting bacterial infections.

35. Deficiency;
Severe deficiency of vitamin C leads to a disease named scurvy. Scurvy is characterized by
easy bruising and hemorrhaging of the skin, loosening of the teeth, bleeding of the gums and
disruption of the cartilages supporting the skeleton.
Recommended amount of vitamin C for different age groups is as follows:
The benefits of vitamin C may include protection against immune system
deficiencies, cardiovascular disease, prenatal health problems, eye disease,
and even skin wrinkling

36. Sources of Ascorbic Acid
The main sources of Vitamin C are raw and fresh vegetables. Orange, grape, lime and lemon
are especially very rich in vitamin C. Other sources of this Vitamin include Bell peppers,
Broccoli, kiwi, Strawberries etc.

37. Vitamin D: Cholecalciferol
Two distinct forms of Vitamin
Cholecalciferol (Vitamin D3) is the natural form of the vitamin D occurring in foods. It can
be formed under the skin from 7-dehydrocholesterol by the influence of sunlight/UV
radiation.
Ergocalciferol (vitamin D2) is a synthetic form of the vitamin D which has the same
activity as the natural vitamin. It is produced by the UV radiation of ergosterol, a
compound which can be extracted from yeast. This form of vitamin is added to margarine
and baby foods.
Functions:
 Vitamin D is essential for the development of bones and teeth.
 Vitamin D also helps in strength and repair of bones and teeth.
 Vitamin D is important for absorption of calcium (Ca) and phosphorus (P) from the
small intestine.
 Vitamin D helps in uptake of calcium (Ca) and phosphorus (P) by the bones and teeth.

38. Deficiency
Children receiving an inadequate supply of vitamin D develop rickets due to inadequate
deposition of calcium and phosphorus in bones. Premature infants are more susceptible to
rickets than full term infants. In adults inadequate supply of vitamin D causes osteomalacia,
a condition in which the bones become soft, weak and painful.
Fat helps in the absorption of vitamin D and bile is essential for its
absorption. Vitamin D enters into the general circulation via lymph
and is largely stored in liver and kidneys.

39. Sources of vitamin D
Vitamin D is not widely distributed in nature and the best sources are fish liver
oil. Milk, butter and egg yolk are the only foods in the ordinary diet that contain
vitamin D. Vitamin D can also be obtained by exposure to sunlight.

40. Vitamin E: α-Tocopherol (Beauty Vitamin)
Functions:
 The principal role of vitamin E appears to be as an antioxidant. By accepting oxygen,
vitamin E can prevent the oxidation of vitamin A in the intestinal tract, thus making vitamin
A available for body use.
 Vitamin E also reduces the oxidation of the poly unsaturated fatty acids, thereby helping to
maintain normal cell membrane.
 It protects the red blood cells against hemolysis.
 Vitamin E is required by animals and by humans for the normal reproductive processes.
 It also plays an important protective role during ageing of cells.
Deficiency of vitamin E
Vitamin E deficiency causes the following disorders in animals
Reproductive failure
Hemolysis of red blood cells
Muscular dystrophy

41. Sources: Wheat germ oil & corn germ oil are the rich natural sources whereas the
Vegetable oils and the fats are good sources while Cereals and animal foods are fair sources
of vitamin E.

42. Vitamin K: Menaquinone
 Vitamin K is also known as the antihemorrhagic vitamin. The following are the three
compounds with biological activity similar to vitamin K,
Phylloquinone which can be generally obtained in green leafy vegetables
Menaquinones which are synthesized by the intestinal bacteria
Menadione which is a synthetic compound. It yields Phylloquinone on metabolism
 Functions:
It is mainly needed for formation of prothrombin, a substance necessary for blood clotting.
Intestinal bacteria normally synthesize substantial amounts of vitamin K.
 Deficiency of vitamin K
The deficiency of vitamin K results in low prothrombin level and increased blood clotting time.
Consequently, deficiency of vitamin K lead to hemorrhagic and bleeding conditions not only in
adults but also in infants and new borns.
 Vitamin K requirement depends on the amount of vitamin K formed by the intestinal bacteria.
The more the endogenous vitamin K formation, less will be the dietary requirement.

43. Sources of vitamin K
 The best sources of vitamin K are the green leafy vegetables like spinach, cabbage etc.
 Good sources of vitamin K are cauliflower, wheat germ, etc.
 Carrots and potatoes are fair sources. Milk, meat and fish are poor sources

44. T H A N K
Y O U
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