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Vitamins B group Vitamin B1 (Thiamine) Vitamin B2 (Riboflavin)

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Presentation on theme: "Vitamins B group Vitamin B1 (Thiamine) Vitamin B2 (Riboflavin)"— Presentation transcript:

1 Vitamins B group Vitamin B1 (Thiamine) Vitamin B2 (Riboflavin)
Vitamin B3 or Vitamin P or Vitamin PP (Niacin) Vitamin B5 (Pantothenic acid) Vitamin B6 (Pyridoxine and Pyridoxamine) Vitamin B7 or Vitamin H (Biotin) Vitamin B9 or Vitamin M and Vitamin B-c (Folic acid) Vitamin B12 (Cyanocobalamin)

2 Vitamin B1 (Thiamine) Composed of a substituted pyridine and thiazole ring. Thiamine (vitamin B1) was the first of the water-soluble B-vitamin family to be discovered.

3 Natural Sources Thiamine are found in many nuts, seeds, brown rice, seafood, and whole-grain products (Grains are stripped of the B vitamin content during processing). Sunflower seeds are a particularly good source. Legumes, milk, and beef liver.

4 Stability Thiamine is destroyed by prolonged heat.
Food should be cooked in small amounts of water so that thiamine and other water-soluble vitamins don't leach out. Baking soda should not be added to vegetables as it breaks Vitamin B1. Avoid sulfite preservatives as it breaks Vitamin B1. Drinking tea with a meal will also drastically decrease the amount of thiamine that is absorbed by the body. Vitamin B1 is stable in acid, unstable in aqueous solutions of PH more than 5. It is readily oxidized by exposure to the atmospheric oxygen or by oxidizing agents to thiochrome. (blue fluorescence), used for the quantitative fluoremetric assay

5 Role of Thiamine It is an Co-factor for carbohydrates metabolism (Kreb’s Cycle). This role enable conversion of blood sugar (glucose) into biological energy. This is important for: Provide energy to the brain. Improve transmission of nerve impulses through the nerves by providing them with energy. Proper function of the heart muscles. Healthy mucus membrane. Maintenance of smooth and skeletal muscles. Formation of RBC’s.

6 In mammalian cells: Thiamine pyrophosphate (TPP) is a coenzyme for:
Thiamine HCl is converted to Thiamine Pyrophosphate Co-factor using ATP. Thiamine pyrophosphate (TPP) is a coenzyme for: pyruvate dehydrogenase. α-ketoglutarate dehydrogenase. These enzymes function in the metabolism of carbohydrates. Transketolase. Transketolase functions in: The pentose phosphate pathway to synthesize NADPH. The pentose sugars deoxyribose and ribose involved in nucleic acids biosynthesis.

7 Required Daily Amount The daily requirements are based on the number of calories in diet. It is about 0.5 mg/1000 calories. Average 1.5 mg/ day for 3000 calories. Daily requirement increase with high carbohydrate intake and for hard worker or athletes.

8 Structure Activity Relationship (SAR)
Essential features for activity: Methylene bridge. Amino group in the pyrimidine ring. Hydroxy ethyl group at the thiazole ring. Methyl group of pyrimidine ring, when replaced by: a- Ethyl or propyl groups gives an active compound. b- Butyl group gives inactive compound.

9 Vitamin antagonists Oxythiamine is a competitive inhibitor.
Neopyrithiamine prevent phosphorelation of hydroxy ethyl group that is essential for activity of the vitamin. Thiaminase in raw fish destroy vitamin B1

10 Diagnostic Testing for B1 Deficiency
Causes of Deficiency A lack of thiamine can be caused by: Malnutrition. A diet high in thiaminase-rich foods (raw freshwater fish, raw shellfish, ferns) Foods high in anti-thiamine factors (tea, coffee, nuts). Chronic consumption of alcohol. Diagnostic Testing for B1 Deficiency A diagnosis test for B1 deficiency can be determined by measuring transketolase levels of erythrocyte

11 Deficiency Beriberi: The syndrome typically causes poor appetite, abdominal pain, heart enlargement, constipation, weakness, swelling of limbs, muscle spasms, insomnia, and memory loss (all reversed on treatment). Wernicke-Korsakoff syndrome: Resulted from untreated Beriberi and characterized by confusion, disorientation, inability to speak, numbness or tingling of extremities, edema, nausea, vomiting, visual difficulties, and may progress to psychosis, coma, and death. Even in advanced states, this condition can be reversible if B1 is given.

12 Risk Factors for Deficiency
The leading risk factor for thiamine deficiency is alcoholism. Alcohol acts directly to destroy thiamine and increases it’s excretion. Liver cirrhosis, malabsorption syndromes, diabetes, kidney disease, or hypermetabolic conditions also have increased susceptibility to B1 deficiency. The elderly peoples with poor nutritional status and difficulties with absorption. Others with nutritionally inadequate diets, or an increased need as a result of stress, illness, or surgery may benefit from additional vitamin B1 intake. Use of tobacco products, or carbonate and citrate food additives can impair thiamine absorption.

13 Side Effects Interactions
In very unusual, large doses of thiamine may cause rashes, itching, or swelling. These reactions are more common with intravenous injections than oral supplements. Interactions Oral contraceptives, antibiotics, sulfa drugs, and certain types of diuretics may lower thiamine levels in the body. Taking this vitamin may also intensify the effects of neuromuscular blocking agents that are used during some surgical procedures. B vitamins are best absorbed as a complex, and magnesium also promotes the absorption of thiamine

14 Riboflavin, lactoflavin, Vitamin G
Vitamin B2 Riboflavin, lactoflavin, Vitamin G It chemically has a three rings structure (isoalloxazine) linked to ribityl moiety. Riboflavin is a yellow to orange- yellow powder, soluble in water (1:3000 to 1:20000) due to internal crystalline structure, urea or niacinamide are used to solubilize riboflavin when high concentrated solution needed.

15 Natural Sources Other sources: Milk, cheese, egg white and liver.
leafy green vegetables, almonds and mature soybeans Yeast. Other sources: Added as food colouring Fortify some foods as baby foods, breakfast cereals, sauces, processed cheese, fruit drinks and vitamin-enriched milk).

16 Required Daily Amount Stability
mg/day. Stability Vitamin B2 is unstable to light in both acidic and basic medium. Under acidic condition light produce lumichrome. In alkaline PH light produce lumiflavin. Both are inactive biologically.


18 Role of Vitamin B2 Riboflavin is converted to the active forms:
Riboflavin-Mononucleotide more correct Riboflavin-Monophosphate (FMN). Riboflavin-Adenine Dinucleotide more correct Riboflavin-Adenine Diphosphate (FAD). The Active forms work as co-enzymes for about 150 oxidation-reduction reactions involved in: Carbohydrate, Proteins and fat metabolism Activation of vitamin B12 and folate. Protection of erythrocytes and other cells from oxidative stress.

19 Absorption Riboflavin is absorbed in the proximal intestine.
Riboflavin is stored mainly in the liver, kidney and heart in the form of FAD (70- 90%) or FMN or Riboflavin.

20 Causes of Riboflavin Deficiency
Not getting enough of the vitamin from the diet. A result of conditions that affect absorption in the intestine. The body not being able to use the vitamin. An increase in the excretion of the vitamin from the body.

21 Ariboflavinosis Symptoms of riboflavin deficiency: Cracked and red lips. Inflammation of the lining of mouth and tongue. Mouth ulcers, angular cheilitis. Dry and scaling skin and iron-deficiency anemia. The eyes become bloodshot, itchy and sensitive to bright light. Angular cheilitis: is an inflammatory lesion at the corner of the mouth. Usually associated with a fungal (Candidal) or bacterial (Staphylococcal) infection The condition manifests as deep cracks or splits. In severe cases, the splits can bleed when the mouth is opened.


23 Diagnostic Testing of B2 Deficiency
A positive diagnostic test of serum riboflavin by measuring glutathione reductase levels of erythrocytes.

24 Risk Factors for Deficiency
People under high stress, including those experiencing surgery, chronic illnesses, liver disease, or poor nutritional status. Diabetics have a tendency to be low on riboflavin as a result of increased urinary excretion. Athletes, and anyone else with a high-energy output will need additional vitamin B2. The elderly due to nutritional inadequacy as well as problems with absorption.

25 Smokers and alcoholics are at higher risk for deficiency as tobacco and alcohol suppress absorption.
Birth control pills may possibly reduce riboflavin levels, as can phenothiazine tranquilizers, tricyclic antidepressants, and probenecid. Recent advances in human genetics indicate that certain genotypes are at greater risk for riboflavin deficiency than others.

26 Uses High doses of riboflavin(400 mg/day) have been shown to reduce the frequency and severity of migraine headaches by half in susceptible people. Riboflavin help decrease the incidence of cataracts. Improve memory. Riboflavin and vitamin C both help boost the body's level of glutathione which is an antioxidant. Healthy development of the fetus.

27 Interactions Probenecid (anti-gout) and propantheline bromide (anti-peptic ulcers) both delays and impairs absorption. Phenothiazines (antipsychotic drugs) increase the excretion of riboflavin, thus lowering serum levels. Oral contraceptives may also decrease serum levels. Tricyclic antidepressants may lower the levels of riboflavin in the body. Absorption of riboflavin is improved when taken together with other B vitamins and vitamin C. Riboflavin interferes with the absorption and effectiveness of anti-malarial (ex. chloroquine), tetracycline antibiotics and sulfa-containing drugs.

28 Assay Direct fluoremetry.
Lumiflavin method in which riboflavin is irradiated in alkaline medium to yielded a chloroform-soluble lumiflavin, measured fluoremetry. It is preferred in biological samples.

29 Vitamin B3 (Niacin, Nicotinic acid, Nicotinamide, Vitamin P, Vitamin PP)

30 Natural Sources Tuna is one of the best sources of niacin.
Most processed grain products are fortified with niacin. Cottage cheese, milk are highest in Tryptophan and about half of the Tryptophan consumed is used to make niacin.

31 Required Daily Amount About 7 mg/ 1000 calories. mg/day.

32 Role of Vitamin B3 It is act as co-enzyme in oxidation-reduction reactions: Catabolic reactions: NAD+/NADH Anabolic reactions: NADP+/NADPH

33 Pharmacokinetics Absorption: Transportation: Biosynthesis:
At low concentration by active transportation. At high concentration by passive diffusion. Transportation: Both Nicotinic acid (NA) AND Nicotinamide (NAm) bind to plasma proteins for transportation. Biosynthesis: The liver can synthesize Niacin from the essential amino acid Tryptophan, but the synthesis is extremely slow and requires vitamin B6 (60 mg of Tryptophan= 1mg of niacin). Bacteria in the gut may also perform the conversion but are inefficient.

34 Required Daily Amount mg/day

35 Deficiency Pellagra: A serious deficiency of niacin. The main results of pellagra can easily be remembered as "the four D's": diarrhea, dermatitis, dementia, and death. It is very rare now, except in alcoholics, strict vegetarians, and people in areas of the world with very poor nutrition. Milder deficiencies of niacin can cause dermatitis around the mouth and rashes, fatigue, irritability, poor appetite, indigestion, diarrhea, headache.


37 Risk Factors for Deficiency
Vegans, and others who do not eat animal protein, should consider taking a balanced B vitamin supplement. Others people under high stress, chronic illnesses, liver disease may need extra niacin and other B vitamins. People over 55 years old are more likely to have a poor dietary intake. Certain metabolic diseases also increase the requirement for niacin. Those who abuse nicotine, alcohol or other drugs are very frequently deficient in B vitamins, but use of niacin with alcohol can cause seriously low blood pressure.

38 General Uses Niacin in very large doses (2-3 g/day) is used to decrease blood cholesterol levels and reduce the risk of heart attack. In certain conditions (gout, diabetes, peptic ulcer, liver or kidney disease, and high blood pressure). Niacinamide used on a long-term basis to prevent the onset of juvenile diabetes (children). Treatment of Pellagra.

39 Side Effects In large amounts Niacin commonly causes flushing and headache. This can be avoided by taking it in the form of inositol hexaniacinate.

40 Interactions Niacin with high blood pressure medication may cause hypotension. Isoniazid inhibits the body's ability to make Niacin from tryptophan. Extra niacin may be required. Supplements may also be needed by women taking oral contraceptives. Cholestyramine and cholestipol (medications to lower cholesterol) should be taken at a different time than Niacin or they will reduce its absorption.

41 Transdermal Nicotine used with Niacin is likely to cause flushing and dizziness.
Carbamazepine (an antiseizure medication) is more likely to cause toxicity in combination with niacin. Nicotinic acid reacts with hemoglobin and myoglobin in meat to form a brightly coloured complex, and thus has been used as a food additive, typically to improve the colour of ground meat. Concomitant use of Niacin with Statin class drugs to lower cholesterol can cause myopathy.

42 Vitamin B5 (Pantothenic acid)
It is a peptide substance composed of Pantoic acid and b-Alanine. It can be present as the Calcium salt or the Alcohol “Pantothenol”.

43 Natural Sources Animal Sources: Plant Sources: Honey and Molasses.
Liver, kidney and Heart. Milk and Milk Products (Cheese, Yogurt and Butter). Plant Sources: Cereals Honey and Molasses. Yeasts.

44 Role of Vitamin B5 It is a part of Co-enzyme A that assists the following reactions: Formation of Sterols (Cholesterol and 7-Dehydrocholesterol). Formation of Fatty acids. Formation of Keto acids such as Pyruvic acid.

45 Required Daily Amount Deficiency
4 Years and over 10 mg Less than 4 years 5 mg Infants 3 mg Deficiency Rare to occur. When occur it leads to Paresthesias (is a sensation of tingling, pricking, or numbness of a person's skin).

46 Uses: Treat and prevent deficiency state.
Supplements in cases of inadequate diet. It is Described for: Diabetic neuropathy. Arthritis. In hair dyes.

47 Uses of Dexpantothenol
Topically for: Burning Itching Irritation To Relive gas retention.

48 Vitamin B6 Pyridoxine

49 Natural Sources Vitamin B6 is found in: Cereals, Beans, Meat, Liver, Fish, Yeast, Nuts and some fruits as Banana and Potatoes. It is also produced by bacterial flora in the colon.

50 Role of Vitamin B6 Vitamin B6 is needed for more than 100 enzymes involved in protein metabolism. It is also essential for red blood cell metabolism and hemoglobin formation. The nervous and immune systems need vitamin B6 to function efficiently. It is also needed for the conversion of Tryptophan (an amino acid) to Niacin (Vitamin B3). Vitamin B6 also helps maintain blood glucose within a normal range. When caloric intake is low vitamin B6 help to convert stored carbohydrate or other nutrients to glucose to maintain normal blood sugar levels.

51 Required Daily Amount Babies under six months 0.3 mg
Babies Six months to one year old 0.6 mg. Children 1- 3 years old 1.0 mg 4- 6 years old 1.1 mg 7- 10 years old 1.4 mg Males aged years 1.7 mg 15 years and older 2.0 mg Females years 1.4 mg Female years 1.5 mg Women age 19 years and older 1.6 mg Pregnancy 2.2 mg Lactation (2.1 mg). Adults mg

52 Causes of Deficiency Individuals with a poor quality diet or an inadequate B6 intake. Alcoholics because alcohol also promotes the destruction and loss of vitamin B6 from the body. Older people. Asthmatic children treated with theophylline because it decreases body stores of vitamin B6.

53 Deficiency Signs of vitamin B6 deficiency include:
Skin: Dermatitis (skin inflammation), Stomatitis (inflammation of the mucous lining of any of the structures in the mouth), Glossitis (is inflammation or infection of the tongue ). Neurological abnormalities: Depression, confusion, and convulsions. Vitamin B6 deficiency also can cause anemia.

54 Uses Treatment and Prevention of deficiency.
For people are high risk of deficiency. Can also described in: Acne Kidney stones Premenstrual syndromes Improve some CNS conditions.

55 Side Effects Too much vitamin B6 can result in nerve damage to the arms and legs. This neuropathy is usually related to high intake of vitamin B6 and is reversible when supplementation is stopped.

56 Interaction Some Drugs increase the excretion of Vitamin B6 by the body as: Chloramphenicol. Oral Contraceptives. Cycloserine. Isoniazide. L-Dopa

57 Vitamin B7 (Vitamin H, Biotin, Growth Factor, Co-enzyme R)
It is 2-Imidazolidinone tetrahydrothiophene-4-valeric acid.

58 Natural Sources Liver. Meat. Kidney Yeast Egg yolk Mushrooms
Milk and milk products.

59 Role of Vitamin B7 It is a co-enzyme for several carboxylation reactions. Important for carbon dioxide fixation. Important for Carbohydrates and Fats metabolism. Co-factor for Pyruvate carboxylase.

60 Required Daily Amount Deficiency
mg/day. Deficiency Only induced in experimental animals not observed in human: Skin lesions Retarded growth Hair loss

61 Biotin Antagonists Structural analogs:
Biotin sulfonate Desthiobiotin Imidazolidone acids. Avidin in Raw egg combines and inactivate Biotin.

62 Uses Treat and prevent deficiency conditions.
Supplement in cases of inadequate diet. In vitamin B-Complex to improve glucose metabolism. In skin disease as Acne and Dermatitis.

63 Vitamin B9 (Vitamin M, Vitamin B-c, Folic acid )
Conjugate of Pteridine, p-Aminobenzoic acid and Glutamic acid.

64 Natural Sources Liver. Yeast Fruits Leafy Vegetables
Milk and milk products.

65 Role of Vitamin B9 THF act as Co-enzyme for:
Leucopoiesis (Production of Leukocytes). Erythropoiesis (Production of Erythrocytes). Nucleoprotein synthesis.

66 Required Daily Amount Deficiency
mg/day. Deficiency Very rare due to: Malabsorption (due to alcoholism). Impaired Hepatic functions (due to alcoholism). Leads to: Glossitis (is inflammation or infection of the tongue ). Megaloblastic anemia Leucopenia

67 Biotin Antagonists Structural analogs: Sulfonamides.

68 Uses Treat and prevent deficiency conditions.
Supplement in cases of inadequate diet. Treatment of chronic intestinal and liver diseases.

69 B vitamins Deficiency Vitamin B1 (Thiamine) deficiency causes Beriberi. Symptoms of this disease of the nervous system include weight loss, emotional disturbances, Wernicke's encephalopathy (impaired sensory perception), weakness and pain in the limbs, periods of irregular heartbeat, and edema (swelling of bodily tissues). Heart failure and death may occur in advanced cases. Chronic thiamine deficiency can also cause Korsakoff's syndrome, an irreversible psychosis characterized by amnesia and confabulation. Vitamin B2 (Riboflavin) deficiency causes Ariboflavinosis. Symptoms may include cheilosis (cracks in the lips), high sensitivity to sunlight, angular cheilitis, glossitis (inflammation of the tongue), seborrheic dermatitis or pseudo-syphilis (particularly affecting the scrotum or labia majora and the mouth), pharyngitis, hyperemia, and edema of the pharyngeal and oral mucosa.

70 Vitamin B3 (Niacin) deficiency, along with a deficiency of tryptophan causes Pellagra. Symptoms include aggression, dermatitis, insomnia, weakness, mental confusion, and diarrhea. In advanced cases, pellagra may lead to dementia and death. Vitamin B5 (Pantothenic acid) deficiency can result in acne and Paresthesia, although it is uncommon. Vitamin B6 (Pyridoxine) deficiency may lead to anemia, depression, dermatitis, high blood pressure (hypertension) and elevated levels of homocysteine.

71 Vitamin B7 (Biotin) deficiency does not typically cause symptoms in adults but may lead to impaired growth and neurological disorders in infants. Vitamin B9 (Folic acid) deficiency results in elevated levels of homocysteine. Deficiency in pregnant women can lead to birth defects. Vitamin B12 (Cyanocobalamin) deficiency causes pernicious anemia, memory loss and other cognitive decline. It is most likely to occur among elderly people as absorption through the gut declines with age. In extreme (fortunately rare) cases paralysis can result.

72 (Cyanocobalamin, Antipernicious anemia factor)
Vitamin B12 (Cyanocobalamin, Antipernicious anemia factor)


74 Structure B12 is the most chemically complex of all the vitamins. The structure of B12 is based on a Corrin ring, similar to the Porphyrin ring found in Heme, Chlorophyll, and Cytochrome. The central metal ion is Co (cobalt). Four of the six coordinations od Co are provided by the Corrin ring nitrogens, and a fifth by a dimethylbenzimidazole group. The sixth coordination can be: Cyano group (-CN) Cyanocobolamin Hydroxyl group (-OH) Hydroxycobalamin Methyl group (-CH3) Methylcobalamin (MeB12) 5'-deoxyadenosyl group Adenosylcobalamin (AdoB12).

75 Natural Sources Bacteria such as Streptomycin and Bacillus present in the intestinal flora produce the vitamin required for man and animals. The vitamin is stored in the liver with estimated t1/2 400 days. B12 can be obtained from animal products only such as: Liver and Meat Fish and Eggs Milk and Dairy products

76 Pharmacokinetics Vitamin B12 in food is bound to the protein.
Hydrochloric acid in the stomach releases free vitamin B12. Once released vitamin B12 combines with a substance called intrinsic factor (IF). This complex can then be absorbed by the intestinal tract.

77 Role of Vitamin B12 Essential for the maturation of Erythrocytes.
Protects against Pernicious anemia. Essential for cell growth and reproduction. Essential for the formation of myelin and nucleoproteins.

78 Males and Females (μg/day)
Required Daily Amount Lactation (μg/day) Pregnancy (μg/day) Males and Females (μg/day) Age (y) N/A 0.9 1-3 1.2 4-8 1.8 9-13 2.8 2.6 2.4 14-18 19 and older

79 Causes of deficiency Inability to absorb vitamin B12 from food.
Vegetarians who do not consume any animals products. Stomach or intestinal disorder that limits the absorption of vitamin B12. Inadequate production of intrinsic factor (pernicious anemia). Competition for available B12 by parasites.

80 Symptoms of vitamin B12 deficiency
Pernicious Anemia: It is a type of Megaloblastic anemia characterized by decreased number of enlarged red blood cells. Neurological changes such as numbness and tingling in the hands and feet. Demyelination and irreversible nerve cell death. Difficulty in maintaining balance, depression, confusion, dementia, poor memory. In infants cause movement disorders and delayed development

81 Uses Treat and prevent deficiency conditions in combination with the intrinsic factor. Supplement in cases of inadequate diet or patient receiving antagonists. Radioactive B12 to diagnose Pernicious anemia. In combination with Folic acid to treat Megaloblastic anemia. Large doses (5- 10 g IV) of Hydroxycobalamin used in cyanide poisoning where it combine with cyanide ion to form harmless B12.

82 Interaction Some Drugs interfere with it absorption such as:
Alcohol, Aminosalicylic acid, Colchicine, Neomycin, Cholestyramine (Questran®), anticonvulsants (Phenytoin), the metformin (Glucophage®). Vitamin C supplements can destroy dietary vitamin B12 and should be taken 2 hrs after meals. H2 blockers include cimetidine, Proton pump inhibitors (PPIs) (omeprazole) reduce secretion of gastric acid and pepsin as a result reduce absorption of protein-bound (dietary) vitamin B12.

83 Vitamin C (Ascorbic acid, Anti- Scurvy)
Vitamin C is a water-soluble vitamin. Almost all animals and plants synthesize their own vitamin C. Vitamin C was first isolated in 1928 and in 1932 it was proved to be the agent which prevents scurvy.

84 Chemistry Vitamin C is a weak acid, called Ascorbic acid or its salts “Ascorbate”. It is the L-enantiomer of Ascorbic acid. The D-enantiomer shows no biological activity. Commercial vitamin C is often a mix of Ascorbic acid, Sodium ascorbate and/or other Ascorbates.


86 Sources Vitamin C is obtained through the diet by the vast majority of the world's population. The richest natural sources are fruits and vegetables.

87 Amount Plant source 4 Lettuce 60 Papaya 10 Apricot 3150 plum 3 Cucumber Strawberry Plum 2800 Camu Camu 2 Eggplant 50 Orange Watermelon 2500 Wolfberry Fig 40 Lemon 9 Banana 2000 Rose hip 1 Bilberry cantaloupe Carrot 1600 Acerola 0.5 Horned melon Cauliflower 8 Avocado 190 Red pepper 0.3 Medlar 30 Grapefruit Crabapple 130 Parsley 7 Peach 100 Guava 6 Apple 90 Kiwifruit Blackberry Broccoli 5 Beetroot 80 Loganberry Spinach Pear Redcurrant 20 Mango Tomato Lime Mandarin

88 Chemical Synthesis


90 Stability Ascorbic acid is reversibly oxidized to L- Dehydroascorbic acid on exposure to copper, heat and / or mild alkaline. Both ascorbic and dehydroascorbic acids are physiologically active forms of vitamin C. Further oxidation of L- Dehydroascrbic acid to 2,3-Diketo- gluconic acid and oxalate is irreversible. Ascorbic acid is strong reducing agent, serves as an anti-oxidant and co-factor in hydroxylation reactions.

91 Required Daily Amount Adults: 60 mg/day Children: 30 mg/day

92 Role of Vitamin C It is a cofactor in the synthesis of norepinephrine from dopamine. Vitamin C is also involved in a variety of metabolic processes including oxidation-reduction reactions and cellular respiration, carbohydrate metabolism, synthesis of lipids and proteins. vitamin C are attributed primarily to antioxidant and free radical scavenging effects that maintain proper immune system.

93 T-lymphocyte activity, phagocyte function, leukocyte mobility, and possibly antibody and interferon production seem to be increased by vitamin C. Involved in the synthesis of Collagen the major component of ligaments, tendons, cartilages and skin. Involved in tyrosine metabolism.

94 Vitamin C deficiency Fatigue, personality changes, decline in psychomotor performance and motivation. Vitamin C deficiency over 3-5 months results in Symptomatic Scurvy: In Adults: Scurvy leads to the formation of liver spots on the skin, spongy gums, and bleeding from all mucous membranes. The spots are most abundant on the thighs and legs, and a person with the ailment looks pale, feels depressed, and is partially immobilized. In advanced scurvy there are open, suppurating wounds and loss of teeth. Severe scurvy may progress to neuritis, jaundice, fever, dyspnea, and death.

95 In infants, symptoms: anorexia, irritability, growth retardation, thigh tenderness, pseudoparalysis, bleeding around the lower ends of the leg bones (femur and tibia) causing pain. If left untreated, scurvy can proceed to collagen deficiency, seizures, shock or sudden death. It was common between Sailors, Pirates and others who were on ships that were out to sea longer than perishable fruits and vegetables could be stored.

96 Diagnosis of Scurvy Fasting blood ascorbic acid levels:
levels below 0.10 mg/dL are considered deficient. levels of mg/dL are considered low. levels of 0.2 mg/dL or greater are acceptable levels greater than 0.6 mg/dL likely rule out scurvy. White blood cell ascorbic acid concentration is considered a more accurate measurement of vitamin C nutritional status: with a level of zero suggesting scurvy. 0-7 mg/dL suggesting deficiency. 8-15 mg/dL considered low. 15 mg/dL or greater is adequate vitamin C status.

97 Uses Oral Vitamin C: Preventing and treating scurvy.
Preventing deficiency in people with gastrointestinal diseases and those on chronic total parenteral nutrition or chronic hemodialysis. Increasing iron absorption from the gastrointestinal tract. Increasing the healing rate of wounds, burns, fractures, ulcers, and pressure sores. Preventing and treating the common cold and other viral infections, bronchitis, human immunodeficiency virus (HIV) disease.

98 Topically Vitamin C is used for:
Improving skin conditions, protecting against free radicals and pollutants. Improving photo-aged skin. It is also applied topically for ulcerative mucositis associated with radiation therapy.

99 Parenterally Vitamin C is used for:
Preventing and treating vitamin C deficiency. Correcting tyrosinemia in premature infants on high-protein diets.

100 Other Effects of Vitamin C
Decrease the risk of atherosclerosis and peripheral arterial disease. decrease the risk of developing mouth cancer and other cancers. Taking high doses of vitamin C orally might decrease the duration of cold symptoms by doses of at least 2 g/day. Taking vitamin C orally seems to decrease gastritis associated with acid suppressive therapy in patients with Helicobacter pylori infection.

101 Topical vitamin C can decrease the degree and duration of erythema.
Vitamin C orally along with antihypertensive medications appears to decrease systolic blood pressure, but not diastolic pressure. Consuming vitamin C from dietary sources seems to lower blood concentrations of lead in cases of toxicity. Reduce risk of Age-related mascular degeneration (AMD).

102 Side Effects Vitamin C is generally regarded as safe in amounts obtained from foods side effects are rarely reported including nausea, vomiting, heartburn, abdominal cramps, and headache. Dental erosion may occur from chronically chewing vitamin C tablets. High doses/toxicity: High doses of vitamin C greater than 2000 mg/day. These include kidney stones, severe diarrhea, nausea, and gastritis. Large doses may precipitate hemolysis in patients with glucose 6-phosphate dehydrogenase deficiency. Vitamin C is metabolized to oxalic acid. Increased consumption increases the urinary concentration of oxalic acid and increases the risk of oxalate stone formation

103 Effect of Vitamin C on some Drugs
Chromium: Vitamin C increases chromium absorption. Copper: High doses of vitamin C (1500 mg daily) can decrease serum levels of copper and the copper transport protein. Grape: Patients with hypertension who take both vitamin C (500 mg/day) and grape seed polyphenols (1000 mg/day) have significantly increased systolic and diastolic blood pressure. Vitamin B12: vitamin C can destroy dietary vitamin B12. Vitamin C supplements must be taken at least 2 hours after meals.

104 Acetaminophen (Tylenol): High doses of vitamin C (3 g) competitively inhibits sulfate conjugation of acetaminophen, increasing the half-life. Aluminum: Vitamin C can increase the amount of (Al) absorbed. Patients with renal failure who take (Al) compounds chronically should avoid vitamin C in doses above the RDA. Aspirin: Acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels . Chemotherapy: Vitamin C (antioxidants) during chemotherapy could reduce the activity of chemotherapy drugs which generate free radicals.

105 Estrogens: Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy including topical products. Warfarin (Coumadin): High doses of vitamin C may reduce the response to warfarin, possibly by causing diarrhea and reducing warfarin absorption.

106 Drugs affect Vitamin C level
Aspirin increases elimination of vitamin C. It reduces tissue and leukocyte uptake of vitamin C, leaving more in the plasma to be filtered into the urine. Diuretics increases urinary losses of vitamin C, due to increased water excretion. Estrogens can reduce vitamin C absorption or increase its breakdown. Smokers have lower plasma levels of vitamin C than nonsmokers due to increased use of vitamin C to counteract free radicals in cigarette smoke.

107 Doses For scurvy, 100-250 mg once or twice daily.
For treating the common cold, 1-3 g daily. During acute stress, vitamin C 1 g 3 times daily For chronic hemodialysis in adults, mg per day is recommended. For preventing sunburn, 2 g of vitamin C and 1000 IU vitamin E has been used.

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