Introduction of Vitamins

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DefinitionDefinitionVitamins are:Vitamins are:

A.A. Natural micronutrient organic Natural micronutrient organic substances.substances.

B.B. Obtained from animals, plants, and Obtained from animals, plants, and microorganisms.microorganisms.

C.C. Having Having specific biochemical functions specific biochemical functions in the in the human body (essential human body (essential for health maintenancefor health maintenance).).

D.D. RequiredRequired inin very tiny ( very tiny (mcgsmcgs) and ) and balancedbalanced amounts.amounts.

E.E. Not made in the body Not made in the body (or not in sufficient (or not in sufficient quantity)quantity)

Exceptions are: Exceptions are: ProvitaminsProvitamins

β-carotenoidsβ-carotenoids can replace can replace Vit. AVit. A..

Tryptophan containing proteins Tryptophan containing proteins can can replace replace Vit. B3 Vit. B3 (niacin).(niacin).

Exposure to sunlight Exposure to sunlight can replace can replace Vit. DVit. D..

Bacteria in the human colon synthesize Bacteria in the human colon synthesize Vit. Vit. K2 K2 menaquinonesmenaquinones, which can be absorbed., which can be absorbed.

F. F. Their Their deficiency resulted in a specific deficiency resulted in a specific diseasesdiseases..

Vitamins def. cont.Vitamins def. cont.

Tips to Remember

They are necessarThey are necessaryy dietary factors, not dietary factors, not produced by the body (produced by the body (except except

vitamin D3vitamin D3).).

They function as They function as co-factorco-factor (regulator) of (regulator) of metabolic reactions in the body.metabolic reactions in the body.

Daily requirement of most vitamins is Daily requirement of most vitamins is around around 1 mg.1 mg.

Classification of VitaminsClassification of Vitamins

Vitamins are classified by their Vitamins are classified by their chemical chemical and and biologicalbiological activityactivity. Till now . Till now 1313 vitamins are vitamins are universally recognized:universally recognized:

1- Fat soluble 1- Fat soluble (lipophilic) (lipophilic) vitamins:vitamins:

Vit. A Vit. A (Retinol, Retinal, Retinoic acid)(Retinol, Retinal, Retinoic acid)

Vit. D Vit. D (Vit. D3: Cholecalciferol, Vit. D2:(Vit. D3: Cholecalciferol, Vit. D2:Ergocalciferol) Ergocalciferol)

Vit. E Vit. E ((α-α-Tocopherol)Tocopherol)

Vit. K Vit. K (Vit. K1: Phylloquinones,Vit. K2: (Vit. K1: Phylloquinones,Vit. K2: Menaquinones)Menaquinones)

2-Water soluble vitamins:2-Water soluble vitamins:

(I) (I) Vit. B groupVit. B group

B1 (Thiamin)B1 (Thiamin)

B2 (Riboflavin)B2 (Riboflavin)

B3 (Niacin)B3 (Niacin)

B5 (Pantothenic acid)B5 (Pantothenic acid)

B6 (Pyridoxine)B6 (Pyridoxine)

B9 (Folic acid)B9 (Folic acid)

B12 (Cyanocobalamin)B12 (Cyanocobalamin)

(II) (II) Vit. C :Vit. C : (l-Ascorbic acid)(l-Ascorbic acid)

(III) (III) Vit. H:Vit. H: (Biotin)(Biotin)

Role of Vitamins in MetabolismRole of Vitamins in Metabolism

Vitamins have catalytic functions (co-factors) in the metabolic reactions and do not act as building substances (that is why the daily requirement is very small).

Since each vitamin has very specific function in metabolism, therefore, its deficiency will adversely affect one or more

biochemical reactions in certain organs and very characteristic deficiency symptoms will appeared.

Cases of Vitamin Deficiency and ToxicityCases of Vitamin Deficiency and Toxicity

(1). (1). AvitaminosisAvitaminosis: any disease caused by chronic : any disease caused by chronic oror longlongterm vitamin deficiency term vitamin deficiency oror caused by a defect caused by a defect in in metabolic conversion, such as tryptophan to metabolic conversion, such as tryptophan to niacin. niacin. It It leads to well defined symptoms leads to well defined symptoms e.g.e.g.

XerophthalmiaXerophthalmia due to due to Vitamin A deficiency.Vitamin A deficiency.

RicketsRickets due to due to Vitamin D deficiency.Vitamin D deficiency.

PellagraPellagra due to due to Vitamin B3 deficiency.Vitamin B3 deficiency.

Beriberi Beriberi due to due to Vitamin B1 deficiency.Vitamin B1 deficiency.

ScurvyScurvy due to due to Vitamin C deficiency.Vitamin C deficiency.

(2). (2). HypovitaminosisHypovitaminosis: Resulted from : Resulted from inadequate supplyinadequate supply of of one or more vitamins. It appears in the form of well one or more vitamins. It appears in the form of well defined symptoms as defined symptoms as skin changesskin changes, , reduced reduced

vitality vitality and and low resistance to infectionslow resistance to infections..

(3). (3). Latent hypovitaminosisLatent hypovitaminosis: A case of : A case of unrecognizable unrecognizable deficiency symptoms but deficiency symptoms but immediately appeared under sudden immediately appeared under sudden stress or stress or exposure to different exposure to different environment.environment.

(4). (4). Hypovitaminosis due to AntiHypovitaminosis due to Antivitaminsvitamins::ThiaminaseThiaminase in raw fish destroy in raw fish destroy Vit. B1Vit. B1..

AvidinAvidin in raw egg forming complex with in raw egg forming complex with biotin (biotin–avidin) prevents biotin (biotin–avidin) prevents absorption of biotin.absorption of biotin.

Linatine Linatine in linseed oil is antagonist to in linseed oil is antagonist to Vit. B6Vit. B6..

55. . HypervitamninosisHypervitamninosis:: A case which develops A case which develops only upon prolonged use of excessive amount only upon prolonged use of excessive amount of vitamins.of vitamins.

Hypervitaminosis AHypervitaminosis A

Symptoms include:Symptoms include:HeadacheHeadacheAbdominal painAbdominal painNausea or vomitingNausea or vomitingLethargyLethargyVisual changesVisual changesImpaired Impaired

consciousnessconsciousness

EXAMPLES:EXAMPLES:

Hypervitaminosis DHypervitaminosis D

Symptoms include:Symptoms include: PolyuriaPolyuria VomitingVomiting ConstipationConstipation HypertensionHypertension Seizures - can be Seizures - can be

fatalfatal

Medicinal applications of VitaminsMedicinal applications of Vitamins

Elimination of Elimination of hypovitaminosishypovitaminosis..

TreatmentTreatment of some diseases. of some diseases.

ProphylaxisProphylaxis against some diseases. against some diseases.

1- Fat soluble vitamins

Vitamins Medicinal applications

A 1 .Lowered resistance to infections.

2 .Dark-adaptation.

D 1 .Prophylaxis and therapy of rickets.

2 .Cases of bone atrophy.

3 .Improves tooth consistency.

E 1. In cardiac, vascular and muscular disorders.

2. Fat with high levels of unsaturated fatty acids absorption disorders.

K 1 .Disorders of blood coagulation.

2- Water soluble vitamins2- Water soluble vitamins

Vitamins Medicinal applications

B1 1. Beri beri.

2. Nervous inflammations, neuralgias.

3. Cardiac dysfunction caused by alcoholism.

B2 1. Ariboflavinosis.

2. Photophobia and blurred vision.

3. Corneal vascularization and eye itching

B3 1. Pellagra.

2. Multiple B-complex deficiency syndrome.

B5 Dermatitis and seborrhea.

2- Water soluble vitamins2- Water soluble vitamins

Vitamins Medicinal applications

B6 1. Irritability and convulsion.2. Hypochromic anemia.3. Peripheral neuritis..

B9 Megaloblastic anemia.

B12 1. Juvenile pernicious anemia.2. Gastrecotomy and celiac disease.3. Long term drug therapy as neomycin.4. Inflammatory lesions.

C 1. Scurvy.2. Poor wound healing.

Cases of addition of Vitamins to foodCases of addition of Vitamins to food

1. 1. Vitaminisation:Vitaminisation: Addition of vitamins to foods which Addition of vitamins to foods which do not necessarily contain them naturally do not necessarily contain them naturally

(Addition of vitamins A and D to margarine)(Addition of vitamins A and D to margarine)..

2. 2. Revitaminisation:Revitaminisation: Restoration of the original vitamin Restoration of the original vitamin contents of food that is lost during processing. contents of food that is lost during processing. ((FlourFlour loss about 70% of its Vit. B content; loss about 70% of its Vit. B content;

Skimmed milk Skimmed milk must be revitaminized with must be revitaminized with Vit. A Vit. A and D as they removed on skimming and D as they removed on skimming with fat).with fat).

3. 3. Standardization:Standardization: Compensation of seasonal Compensation of seasonal variations variations of vitamins in food of vitamins in food (e.g. Milk must (e.g. Milk must standardized standardized due to seasonal variation of due to seasonal variation of Vit. A).Vit. A).

4. 4. Enrichment:Enrichment: Addition of vitamins over the initial Addition of vitamins over the initial natural level e.g. in natural level e.g. in Milk and flourMilk and flour..

5. 5. Stabilization of food:Stabilization of food: Some food products show Some food products show change change in color and taste due to oxidation in color and taste due to oxidation by by light and air. light and air. Vitamins C and E Vitamins C and E ( water and ( water and fat soluble fat soluble antioxidants) are used to protect antioxidants) are used to protect food food from from oxidation and thus saving its oxidation and thus saving its nutritional nutritional value.value.

6. 6. Curing agents:Curing agents: Na ascorbate Na ascorbate is used to reduce the is used to reduce the amount of nitrite and nitrate (food stabilizer).amount of nitrite and nitrate (food stabilizer).

7. 7. Coloring of food productsColoring of food products:: The The carotenoidscarotenoids (natural fat (natural fat soluble pigments and pro-vitamin soluble pigments and pro-vitamin A) and A) and synthetic synthetic carotenoids as: carotenoids as: β-β-carotene, carotene, β-β-apo-8‘-apo-8‘-carotenal, and anthaxanthin are carotenal, and anthaxanthin are suitable for the suitable for the coloring of coloring of margarinemargarine and and cheese.cheese.

Formulation of VitaminsFormulation of Vitamins

Formulation of vitamins must solve the Formulation of vitamins must solve the following problems:following problems: 1.1. Organoleptic characters Organoleptic characters

2.2. Providing accurate known quantities. Providing accurate known quantities.

3.3. Stability. Stability.(a) by addition of stabilizer (as (a) by addition of stabilizer (as

antioxidants)antioxidants)(b) synthesis of stable derivatives(b) synthesis of stable derivatives

4. 4. Solubility.Solubility.transformation of water-soluble vitamins transformation of water-soluble vitamins into into fat soluble derivatives or fat soluble derivatives or vice versa.vice versa.

5.5. Administration route. Administration route.

Extremely sensitive to oxidation by oxygen or Extremely sensitive to oxidation by oxygen or light in presence of metal, heat or moisture.light in presence of metal, heat or moisture.

A. Stabilization for oily form of Vit. A was A. Stabilization for oily form of Vit. A was achieved by:achieved by:

Ester formation Ester formation as acetate or palmitate .as acetate or palmitate .Dissolving in Dissolving in vegetable oilsvegetable oils..Addition of Addition of antioxidantsantioxidants..Using Using complexing complexing agents.agents.

B. Stabilization for water soluble derivatives andB. Stabilization for water soluble derivatives andVit. A dry powder:Vit. A dry powder:

Deposit in gelatin as a carrier substance.Deposit in gelatin as a carrier substance.Use of emulsion form.Use of emulsion form.

Vitamin- AVitamin- A

Vitamin B1 (Thiamine)Vitamin B1 (Thiamine)

Inactivated at neutral or alkaline pH Inactivated at neutral or alkaline pH Unstable in light and moisture Unstable in light and moisture OxidizableOxidizable

1.1. Protect from light and moistureProtect from light and moisture..

2.2. Optimum stability at Optimum stability at pH 3 - 4.5pH 3 - 4.5. .

3.3. In the presence of vitamin B2 it is easily In the presence of vitamin B2 it is easily oxidized oxidized in aqueous solution to in aqueous solution to thiochromethiochrome. .

4.4. Thiamine.HNOThiamine.HNO33 is more stable than is more stable than

thiamine.HCl.thiamine.HCl.

5.5. Protect dry preparation from humidityProtect dry preparation from humidity..

Vitamin B2 (Riboflavin)

Unstable in light, alkaline medium, and with Unstable in light, alkaline medium, and with reducing agents – sparingly soluble in reducing agents – sparingly soluble in water water – unpleasant taste.– unpleasant taste.

1.1.Use solubilizers Use solubilizers e.g. nicotinamide or salicylic e.g. nicotinamide or salicylic acid or acid or use Sodium salt of riboflavin-5'-use Sodium salt of riboflavin-5'-phosphate phosphate more water soluble.more water soluble.

2.2.For oral use, For oral use, formulate it in coated formformulate it in coated form..

3. In aqueous solution it acts as oxidizing agent 3. In aqueous solution it acts as oxidizing agent for Vit. B1, C and folic acid.for Vit. B1, C and folic acid.

Vitamin B5 (Pantothenic acid)Vitamin B5 (Pantothenic acid) Very sensitiveVery sensitive

Its Its Ca and Na Ca and Na salts are more stable in salts are more stable in absence of moisture.absence of moisture.

The The alcohol form alcohol form (Pantothenol; panthenol; (Pantothenol; panthenol; D-pantothenyl alcohol) is used in aqueous D-pantothenyl alcohol) is used in aqueous preparations.preparations.

Vitamin B12 (Cyanocobolamine)Vitamin B12 (Cyanocobolamine)

Stable in acidic medium Stable in acidic medium but unstable at high but unstable at high temperature and in presence of vitamin B1, B3, temperature and in presence of vitamin B1, B3, vitamin C, and some heavy metals.vitamin C, and some heavy metals.

Fat Soluble VitaminsFat Soluble Vitamins

(Vitamin A and Carotenoids)(Vitamin A and Carotenoids)

Vitamin A exists in animal foods in the form of retinol esterified with fatty acids (usually as retinyl palmitate).

In the body retinol can be oxidized to retinal or retinoic acid which have 2 specific functions:

Vitamin A and Carotenoids

Retinal plays a central role in the function of retina. Retinoic acid helps regulate gene expression and cell development.

The 3 compounds The 3 compounds retinol,retinol, retinal and retinal and retinoic acid retinoic acid are collectively are collectively referred as Vit. Areferred as Vit. A. . Vit. A is carried in the blood through a retinol-Vit. A is carried in the blood through a retinol-binding protein (RBP). RBP is synthesize in binding protein (RBP). RBP is synthesize in the liver.the liver.

CarotenoidsCarotenoids (provitamin A) exist in plant (provitamin A) exist in plant foods.foods.

The most common type is β-carotene The most common type is β-carotene which can be absorbed as such or after which can be absorbed as such or after splitting splitting by by intestinal cells intestinal cells into Vit. A . into Vit. A .

A large A large carrot contains carrot contains 15 mg of β-15 mg of β-carotenecarotene which can supply enough which can supply enough vitamin A for daily requirement.vitamin A for daily requirement.

Conversion of Carotenoids to Conversion of Carotenoids to RetinoidsRetinoids

Enzymatic conversion of Enzymatic conversion of carotenoids occurs in carotenoids occurs in intestinal cells or liverintestinal cells or liver, , forming 2 molecules of forming 2 molecules of retinal and finally retinol retinal and finally retinol and retinoic acids.and retinoic acids.

Provitamin A carotenoidsProvitamin A carotenoids Beta-caroteneBeta-carotene Alpha caroteneAlpha carotene Beta-cryptoxanthinBeta-cryptoxanthin

All-All-transtrans-Retinol-Retinol All-All-transtrans-Retinal-Retinal

All-All-transtrans-Retinoic acid-Retinoic acid

11

22

33

4455

6677

88

1111

101099

12121313

14141515

1111

11-11-ciscis-Retinal-Retinal

Structure of different forms of Vitamin AStructure of different forms of Vitamin A

Absorption of Vitamin AAbsorption of Vitamin A

RetinoidsRetinoids Retinyl esters broken down to free retinol Retinyl esters broken down to free retinol in in

small intestine with the help of bile and small intestine with the help of bile and digestive enzymes.digestive enzymes.

Once absorbed, retinyl esters reformed in Once absorbed, retinyl esters reformed in intestinal cells.intestinal cells.

90% of retinoids can be absorbed by this 90% of retinoids can be absorbed by this mode of absorption.mode of absorption.

CarotenoidsCarotenoids Absorbed intact but the absorption rate is Absorbed intact but the absorption rate is

much lower.much lower. Intestinal cells can convert carotenoids into Intestinal cells can convert carotenoids into

retinoids. retinoids.

Source and Concentration of Vit. A and β-CaroteneSource and Concentration of Vit. A and β-Carotene

Foods rich in vitamin A (retinol ) Serving size μgFoods rich in vitamin A (retinol ) Serving size μgBeef liver 100g 9100Beef liver 100g 9100Cod liver oil (very rich source) 10g 2550Cod liver oil (very rich source) 10g 2550Egg 1 whole 110Egg 1 whole 110

Others: kidney, dairy products, butter, fortified margarine.Others: kidney, dairy products, butter, fortified margarine.

Foods rich in β- and other carotenoids Serving size μg Vit. A Foods rich in β- and other carotenoids Serving size μg Vit. A Carrot 1, large 810Carrot 1, large 810Sweet potato 1, large 920Sweet potato 1, large 920Spinach and broccoli 10 g 460Spinach and broccoli 10 g 460

Others: red palm oil apricots, peaches, melon, pumpkin.Others: red palm oil apricots, peaches, melon, pumpkin.

Do you know?Do you know?Natural carotenoid supplements are Natural carotenoid supplements are preferable micronutrients (Why?)preferable micronutrients (Why?)

Answer:Answer:1.They contain, along with β-carotene (the 1.They contain, along with β-carotene (the precursor of Vit. A), a mixture of other precursor of Vit. A), a mixture of other important carotenoids, including important carotenoids, including luteinlutein and and lycopenelycopene, which has additional health , which has additional health benefits: benefits:

LycopeneLycopene (red pigment of tomato) is (red pigment of tomato) is a potent antioxidant and decrease the risk a potent antioxidant and decrease the risk of prostate cancer and cataract.of prostate cancer and cataract.

lutein/zeaxanthin lutein/zeaxanthin (yellow stereo-(yellow stereo-isomeric pigments in leafy vegetables) isomeric pigments in leafy vegetables) which give the yellow colour to the which give the yellow colour to the macula macula lutea lutea in the retina.in the retina.

2. Less toxic than Vit. A.2. Less toxic than Vit. A.

luteinlutein

LycopeneLycopene

Functions of Vitamin A

1. Vision:Vit. A plays a central role in the

transformation of light energy into nerve impulses which perceived by brain as vision.

Deficiency: Night blindness

Role of Vitamin A in VisionRole of Vitamin A in Vision

Retinal Retinal turns visual light into nerve signals in turns visual light into nerve signals in retina of eye.retina of eye.

Retinoic acid Retinoic acid required for structural required for structural components (Cones and Rods) of eye :components (Cones and Rods) of eye :Cones in the retinaCones in the retina

Responsible for vision under bright lightsResponsible for vision under bright lightsTranslate objects to color visionTranslate objects to color vision

Rods in the retinaRods in the retinaResponsible for vision in dim lightsResponsible for vision in dim lightsTranslate objects to black and white visionTranslate objects to black and white vision

Mechanism of Action of Retinal in Night Vision

Rhodopsin,Rhodopsin, is a biological pigment in photoreceptor cells of is a biological pigment in photoreceptor cells of the retina that is responsible for the first events in the the retina that is responsible for the first events in the perception of light. It is extremely sensitive to light, perception of light. It is extremely sensitive to light, enabling vision in low-light conditionsenabling vision in low-light conditions..

Rhodopsin consists of the protein moiety Rhodopsin consists of the protein moiety opsinopsin and a  and a reversibly covalently bound cofactor, reversibly covalently bound cofactor,  11-cis retinal. 11-cis retinal.

The process of night vision occurs via G-protein coupled The process of night vision occurs via G-protein coupled receptors called receptors called opsins opsins which contain which contain the chromophore the chromophore (A chromophore absorbs and transmits (A chromophore absorbs and transmits light energy) light energy) 11-cis 11-cis retinalretinal. . 

When struck by photon, When struck by photon, 11-cis 11-cis retinal undergoes photoisomerization to all-trans retinal undergoes photoisomerization to all-trans retinalretinal which  which changes the conformation of changes the conformation of the the opsin GPCR opsin GPCR (G-protein-(G-protein-coupled receptor) leading to formation of signal cascade coupled receptor) leading to formation of signal cascade massages and sent to brain.massages and sent to brain.

Cessation of dark current takes place.Cessation of dark current takes place.

Mechanism of Action of Retinal in Night VisionMechanism of Action of Retinal in Night Vision

2. Skin and mucus membrane health : Vit. A promotes proper growth of skin epithelial cells and mucous membranes of the respiratory, gastrointestinal, and genitourinary tracts.

Deficiency: Xerosis (mucus-secreting cells are replaced by keratin producing cells) dry skin and dry eye

(xerophthalmia).

Stages of xerophthalmia:Stages of xerophthalmia: ( (Early signs of xerophthalmia include Early signs of xerophthalmia include dry conjunctiva and night blindness).dry conjunctiva and night blindness).

The first occurrence of The first occurrence of Conjunctival xerosis Conjunctival xerosis (glistening (glistening white white plaques formed of thickened epithelium, usually triangular) plaques formed of thickened epithelium, usually triangular) Corneal xerosis Corneal xerosis (haziness or a granular pebbly dryness of the (haziness or a granular pebbly dryness of the cornea) cornea) Corneal ulceration (keratomalacia) Corneal ulceration (keratomalacia) dryness of dryness of conjunctiva and later of cornea.conjunctiva and later of cornea.

XerophthalmiaXerophthalmia

Dry SkinDry Skin

3. Immune system.3. Immune system.

Vit.A increases resistance to infection by:Vit.A increases resistance to infection by:Maintaining the integrity of the skin epithelial Maintaining the integrity of the skin epithelial

cells cells and and mucous membrane barriersmucous membrane barriers against bacteria, viruses, and parasites.against bacteria, viruses, and parasites.

Enhancing antibody production.Enhancing antibody production.

Increasing number and activity of macrophages, Increasing number and activity of macrophages, T cells and natural killer (NK) cells and T cells and natural killer (NK) cells and

enhance production of tumor necrosis enhance production of tumor necrosis factor-factor-alpha (TNF-α).alpha (TNF-α).

Deficiency:Deficiency: Impaired Immunity Impaired Immunity (frequent (frequent infections, especially in respiratory system). infections, especially in respiratory system). In In countries where children are not immunized, countries where children are not immunized, infectious infectious disease like measles have relatively disease like measles have relatively higher fatality rates.higher fatality rates.

4. 4. Hormone synthesisHormone synthesis..Vit. A is required for Vit. A is required for synthesis of steroid synthesis of steroid hormoneshormones (corticosteroids, androgens and (corticosteroids, androgens and estrogens) and production of human growth estrogens) and production of human growth hormone (hormone (GHGH).).

5. Reproduction5. Reproduction..Vit. A maintains sperm count and sperm Vit. A maintains sperm count and sperm motility motility in males. In females, in males. In females, deficiency is deficiency is associated with associated with infertility and spontaneous infertility and spontaneous abortionabortion..

6. Cell growth and development.6. Cell growth and development.

7. Formation of red blood cells.7. Formation of red blood cells.Vit. A plays an important role in Vit. A plays an important role in mobilizing mobilizing ironiron stores to build new red blood cells. stores to build new red blood cells.

Uses of Vitamin A in Prevention & TherapyUses of Vitamin A in Prevention & Therapy

1.1. Treatment of Night blindness.Treatment of Night blindness.

2.2. Treatment of Skin/scalp Disorders: Treatment of Skin/scalp Disorders: e.g e.g Psoriasis, Acne vulgaris, Psoriasis, Acne vulgaris, Dandruff, Dandruff, Eczema, Premature aging of skinEczema, Premature aging of skin

3.3. Help in treatment of Help in treatment of ear infections, ear infections, conjunctivitis, bronchitis, pneumonia, and conjunctivitis, bronchitis, pneumonia, and infectious diarrheal disease.infectious diarrheal disease.

4.4. Cancer treatmentCancer treatment: large doses of retinoic acid : large doses of retinoic acid may reduce growth and recurrence of certain may reduce growth and recurrence of certain forms of skin cancer. forms of skin cancer.

5. 5. Cosmetics:Cosmetics: Vit. A derivatives are used Vit. A derivatives are used as anti-as anti-agingaging, being absorbed through the skin and , being absorbed through the skin and increases the rate of skin turnover, and a increases the rate of skin turnover, and a temporary increase in collagen giving a more temporary increase in collagen giving a more youthful appearance.youthful appearance.

6. Gastric ulcers:6. Gastric ulcers: Vit. A maintain gastric mucus Vit. A maintain gastric mucus production and reduce stress ulceration in production and reduce stress ulceration in traumatized or burned patients.traumatized or burned patients.

7. Combination of iron + Vit. A7. Combination of iron + Vit. A may be effective may be effective than iron alone in treating iron-deficiency than iron alone in treating iron-deficiency anemiaanemia..

1.1. Consumers of alcoholic beverage Consumers of alcoholic beverage are liable to are liable to Vit. A deficiency .Vit. A deficiency .

2.2. Patients taking Patients taking some medicationssome medications (birth control (birth control pills, methotrexate, drugs sequestering bile pills, methotrexate, drugs sequestering bile acids e.g. cholestyramine or chitosan).acids e.g. cholestyramine or chitosan).

3.3. Chronically ill people or recovering from Chronically ill people or recovering from surgery.surgery.

4.4. Patients under cancer treatment Patients under cancer treatment (radiation and (radiation and chemotherapy).chemotherapy).

5.5. Cases that may impair Vit. A balance (chronic Cases that may impair Vit. A balance (chronic diarrhea, cystic fibrosis, and kidney or liver diarrhea, cystic fibrosis, and kidney or liver disease).disease).

PEOPLE AT GREATER RISK OF PEOPLE AT GREATER RISK OF DEVELOPING DEVELOPING VITAMIN A VITAMIN A DEFICIENCYDEFICIENCY

Vitamin A ToxicityVitamin A Toxicity1.1. InfantsInfants and and childrenchildren are more susceptible than are more susceptible than

adults adults to vitamin A toxicity.to vitamin A toxicity.

2.2. Vitamin A is a Vitamin A is a teratogenteratogen and high doses ( and high doses (more than more than 10000 μg retinol) may produce birth defects10000 μg retinol) may produce birth defects, ,

even even with exposure for 1week in early pregnancy.with exposure for 1week in early pregnancy.

3.3. Pregnant women should avoid excess intake of Pregnant women should avoid excess intake of vitamin A vitamin A from supplements and from from supplements and from vitamin vitamin A- rich foods, such as liver (100 g contains A- rich foods, such as liver (100 g contains nearly nearly 10000 μg retinol).10000 μg retinol).

4.4. Daily dose should not exceed 2500 μg during Daily dose should not exceed 2500 μg during pregnancy pregnancy or better replaced by cartenoids (their or better replaced by cartenoids (their conversion to Vit. A in the body is tightly conversion to Vit. A in the body is tightly regulated, thus carotenes do not produce regulated, thus carotenes do not produce vitamin vitamin A toxicity).A toxicity).

Signs and Symptoms of Vitamin A toxicity Signs and Symptoms of Vitamin A toxicity

1.1. Bone pain and joint swelling.Bone pain and joint swelling.

2.2. Nausea , vomitting and diarrhoea.Nausea , vomitting and diarrhoea.

3.3. Dry skin and lips.Dry skin and lips.

4.4. Hair loss.Hair loss.

5.5. Headache and blurred vision.Headache and blurred vision.

6.6. Enlargement of the liver and spleenEnlargement of the liver and spleen..

7.7. Reduced thyroid activity.Reduced thyroid activity.

8.8. High blood calciumHigh blood calcium

Drug interactions with Vitamin ADrug interactions with Vitamin A

1. Other retinoid medications has higher risk of cumulative toxicity with Vit. A supplement.

2. Use of mineral oil impairs absorption of all fat soluble vitamins, including A.

3. Cholesterol-lowering drugs (e.g. cholestyramine) and Aluminium-containing antacids inhibit absorption of Vit. A.

4. Alcohol, barbiturates, caffeine, cortisone, tobacco, and very high levels of Vit. E deplete Vit. A.

5. Over use of alcohol and Vit. A together increase the possibility of liver damage.

Some Products of Synthetic Retenoids (orally or Some Products of Synthetic Retenoids (orally or topically)topically)

13-cis-Retinoic acid (Tretinoin or Accutane)13-cis-Retinoic acid (Tretinoin or Accutane)

Used in treatment of acneUsed in treatment of acne

EtretinateEtretinate AcitretinAcitretin

Used in treatment of psoriasisUsed in treatment of psoriasis

THANX