Vitamins 2 The Nature of Vitamins - PowerPoint Presentation

1. Vitamins

2. 2The Nature of VitaminsVitamins were discovered at the beginning of the twentieth century.An essential, non-caloric, organic nutrient needed in tiny amounts in the diet for normal function, growth and maintenance.They are not a source of calories.

3. Vitamins may be considered as organic compounds required in the diet in small amounts to perform specific biological functions for normal maintenance of optimum growth and health of the organism.The Nature of Vitamins

4. There are about 15 vitamins, essential for humans.They are classified as fat soluble and water soluble vitamins.Fat soluble: A, D, E and KWater soluble: C and B group.The B complex vitamins may be sub divided into (B1, B2, B6, biotin etc) and hematopoietic (folic acid and B12).The Nature of Vitamins

5. 5Classification of Vitamins

6. 6Fat Soluble VitaminsVitamins A, D, E and KRequire bile for absorption, dissolve in fat before they are absorbed in the blood stream to carry out their functions.Excesses of these vitamins are stored in the liver.Because they are stored, they are not needed every day in the diet.

7. 7Vitamin A

8. 8In plants, vitamin A only exists in its precursor form.Beta-carotene, the most abundant of these carotenoid precursors, has the highest vitamin A activity.Retinol (active form stored in the liver) converted by cells into its other two active forms, retinal and retinoic acid, as neededImportant for sightDeficiency causes ~500,000 cases of “night blindness” worldwideGenetically engineered rice with high Vitamin A can prevent night blindnessVitamin A

9. Vitamin A plays a role inGene expressionVisionMaintenance of body linings and skinImmune defensesGrowth of bones and of the bodyNormal development of cellsReproductionVitamin A

10. Vitamin A is part of the rhodopsin molecule, a pigment within the cells of the retina.When light falls on the eye, it bleaches rhodopsin, which breaks off the vitamin A, initiating a signal that conveys the sensation of sight to the optic center of the brain.Vitamin A and Eyesight

11. A more serious deficiency of vitamin A occurs when the protein keratin accumulates and clouds the eye’s outer vitamin A-dependent part, the cornea.Keratinization of the cornea can lead to xerosis (drying) and then progress to thickening and permanent blindness, xerophthalmia.About 500,000 of the world’s vitamin A-deprived children become blind each year due to xerophthalmia.Vitamin A and Eyesight

12. Vitamin A is needed by all epithelial tissue which includes the protective linings of the lungs, intestines, vagina, urinary tract, and bladder. If vitamin A is deficient, cells fail to make mucus and secrete keratin, the same protein found in hair and nails. Keratinization makes the tissues dry, hard and cracked which makes they are more susceptible to infection.Vitamin A and Skin

13. Vitamin A has a reputation as an “anti-infective” vitamin.Body’s defenses depend on an adequate supply.Vitamin A assists in growth of bone (and teeth).In children, failure to grow is one of the first signs of poor vitamin A status.Vitamin A and Immunity & Growth

14. Animal Sources EggsMeatCheeseMilkLiverKidneyCodFish oil Plant SourcesMost are orange or yellow in color CarrotsSweet PotatoesCantaloupePink GrapefruitApricotsBroccoliSpinachVitamin A Sources

15. 15Also known as Calciferol due to its role in calcium absorptionMain role is to maintain calcium and potassium levelsIt is the only fat soluble vitamin that can be synthesized with the presence of sunlightCan be made from cholesterol Vitamin D

16. Role of Vitamin DVitamin D functions as a hormone to:Regulate blood calcium and phosphorus levels, thereby maintaining bone integrityTo replenish blood calcium, Vitamin D Works in three ways:Increases Calcium Absorption from the G.I. tractHelps to withdraw calcium from boneIncreases calcium retention in the kidney.

17. Vitamin D stimulates maturation of cells, including immune cells that defend against diseaseVitamin D acts on genes, affecting how cells grow, multiply, and specializeDeficiencies may includeHigh blood pressureSome common cancersRheumatoid arthritisMultiple sclerosisPsoriasisRole of Vitamin D

18. Body makes it own:Dehydrocholesterol in the skin exposed to sunlightEnergy transforms it into a pre-vitamin D moleculeBody heat provides energy to change pre-vitamin D into inactive Vitamin DInactive Vitamin D activated in two stepsFirst, in the LiverSecond in the KidneyWhether made with the help of sunlight or obtained from food, vitamin D undergoes chemical transformations in the liver and kidneys to activate it.Sources of Vitamin D

19. How Vitamin D synthesized by Sunlight?When ultraviolet light from the sun shines on a cholesterol compound in human skin, the compound is transformed into a vitamin D precursor and is absorbed directly into the blood.Over the next day, the liver and kidneys finish converting the precursor to active vitamin D.Sunlight presents no risk of vitamin D toxicity; sun breaks down excess vitamin D in the skin.

20. Vitamin D DeficienciesIn children: Rickets (malformed bones, bow legs)In adults: Poor mineralization of bone results in osteomalacia.most often occurs in women with low Calcium intake, repeated pregnancies, low sun-exposure, and long breastfeeding with infantsloss of Calcium from bone and change of shapeBrittle, soft, and deformed bones

21. Vitamin E Alpha TocopherolTocopherolTocopheryl (Acetate, Succinate)

22. Vitamin E is an antioxidant.Oxidative damage occurs when highly unstable molecules known as free radicals, formed normally during cell metabolism, run amok and disrupt cellular structures. AntioxidantReduce the energy of the free radicalStop the free radical from forming in the first placeInterrupt an oxidizing chain reaction to minimize the damage of free radicals

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24. Protects cell membranes and other fat-soluble parts of the body (LDL cholesterol) from oxidationPrevent oxidation of LDL↓ Atherosclerosis↓ Risk of mortality from Ischemic Heart Disease.Promotes normal growth and developmentPromotes normal red blood cell formationActs as anti-blood clotting agentPlays some role in the body’s ability to process glucoseAlso been known to aid the process of wound healingVitamin E

25. Deficiencies are almost never seen in healthy humans.A classic vitamin E deficiency occurs in premature babies born before the transfer of the vitamin from mother to the infant, which takes place in the last weeks of pregnancy.Infant’s RBC lyse and infant becomes anemicSuppresses the immune system because vitamin E protects White Blood CellsLack of vitality Lethargy Apathy Inability to concentrateMuscle weaknessVitamin E Deficiency

26. Vitamin K

27. Contributes to synthesis of seven blood clotting factorsMain function of vitamin K is to help synthesize proteins that involved in blood clotting.Contributes to the modification of prothrombin to thrombinThrombin is required in the clotting process to convert fibrinogen, to fibrin which is the clotting material.Works as a cofactor for the synthesis an enzyme that makes key bone proteins.Roles of Vitamin K

28. Vitamin K DeficiencyWho is at risk for deficiency?newborns, people on long-term antibiotics Deficiency results in tendency for bleeding.Vitamin K ToxicityToxicity is rare and there is no Tolerable Upper Intake Level.Toxicity causes jaundice and may occur if supplements of a synthetic version are given too enthusiastically.

29. Water-Soluble Vitamins Vitamin C and the B Complex

30. B Complex Vitamins

31. Scientific Names Common NamesThiamin B1Riboflavin B2Niacin Nicotinic acidB6 PyridoxineFolacin Folate, Folic acidB12 Cobalaminpantothenic acidBiotinVitamin B Complex

32. B vitamins act as coenzymesCoenzyme function (coenzymes help enzymes do their jobs)Prosthetic Group: physically become part of an enzyme complexOthers are more loosely attachedMay be part of the active site in the enzyme.The B Vitamins

33. Thiamin, riboflavin, niacin, pantothenic acid, and biotin – participate in the release of energy from the energy nutrientsFolate and vitamin B12 help cells multiplyVitamin B6 helps the body use amino acids to synthesize proteinsB Vitamin Roles in Metabolism

34. B Vitamin Roles in Metabolism

35. B Vitamin DeficienciesIn a B vitamin deficiency, every cell is affected. Symptoms includeNauseaSevere exhaustionIrritabilityDepressionForgetfulnessLoss of appetite and weightImpairment of immune responseAbnormal heart actionTeary, red eyesPain in muscles

36. B1 Thiamin Important in:Producing energy from carbohydratesPlays a critical role in the energy metabolism of all cells. Occupies a site on nerve cell membranes.Proper nerve functionStabilizing the appetitePromoting growth and good muscle toneATP production

37. Thiamin DeficiencyBeri-Berianorexia, fatigue, depressioneffects on cardiovascular systemnervous system

38. B-2 RiboflavinImportant in:Energy productionCarbohydrate, fat, and protein metabolismFormation of antibodies and red blood cellsCell respirationMaintenance of good vision, skin, nails, and hairIt is the central component of the cofactors ( flavin mononucleotide = FMN and flavin adenine dinucleotide = FAD) and is therefore required by all respiratory flavoproteins.

39. B-2 DeficiencyItching and burning eyesBloodshot eyesDermatitisOily skinDigestive disturbances (stomatitis)

40. Participates in energy metabolism of every cell.Important in:energy productionmaintenance of skin and tongueimproves circulationmaintenance of nervous systemhealth of the digestive trackB-3, Niacinamide, Niacin, Nicotinic Acid

41. Cofactor Forms of NiacinIt is converted into nicotiamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphat (NADP) which have vital role in metabolism.It involved in detoxification of xenochemicals, DNA repair, and the production of steroid hormones in the adrenal gland.

42. Biochemical Functions of B-3Oxidation-Reduction Reactions (NAD/NADH)DehydrogenasesElectron Transport SystemInvolved in energy productionSynthetic Pathways (NADPH)FAs. synthesisCholesterol synthesisPurine & Pyrimidine synthesis

43. B-3 Deficiency4 D’s of Niacin deficiency (called pellegra):Dermatitis: skin inflammationDiarrhea: poor absorption, irritation/inflammation of mucous membranesDementia: no energy to think, confused, disorientedDeath: if untreated Gastrointestinal disturbance, loss of appetiteHeadache, insomnia, mental depressionFatigue, aches, and painsNervousness, irritability

44. B-6 Pyridoxine Vitamin B6 participates in more than 100 reactions in body tissues.Important in:Production of red blood cellsconversion of tryptophan to niacin (B-3)

45. B-6 Pyridoxine It is the precursor of pyridoxal phosphat : cofactor for the enzyme aromatic amino acid decarboxylase.ImmunityNervous system functionsReducing muscle spasms, cramps, and numbnessMaintaining proper balance of sodium and phosphorous in the bodyPlays important roles in the synthesis of hemoglobin and neurotransmittersCritical to fetal nervous system development

46. B-6 DeficiencyNervousness, insomniaLoss of muscle control, muscle weaknessConvulsionsArm and leg crampsWater retentionSkin lesions

47. B-12 CobalaminImportant in:proper nerve functionproduction of red blood cellsmetabolizing fats and proteinsprevention of anemiaDNA reproductionenergy production?Vitamin B12 and folate are closely related: each depends on the other for activation.Main roles: helps maintain nerves and is a part of coenzymes needed in new blood cell synthesis.

48. Intrinsic factor is a compound made by the stomach needed for the absorption of B12.A few people have an inherited defect in the gene for intrinsic factor, which makes B12 absorption poor.Vitamin B12 must be injected to bypass the defective absorptive system.This anemia of the vitamin B12 deficiency caused by a lack of intrinsic factor is known as pernicious anemia.Vitamin B12

49. B-12 DeficiencyPernicious anemiaMegaloblastic anemia Methyl-folate trap Delayed or failure of normal cell division due to impaired DNA synthesisNeuropathy defective myelinationprogressive peripheral weakeningunresponsive to folateupper limit to folate supplementation/enrichment

50. FolateFolate: naturally occurring form in foodsFolic acid: synthetic form of folate added to foods and supplementsFolic acids or folacin Latin folium leaf is abundantly found in green leafy vegetables.Functions:Vital for DNA synthesisMaintain new cells, including red blood cellsHelp body use amino acidsReduces risks of some cancers

51. The daily requirement of folic acid is around 200 μg. For women capable of becoming pregnant, it is recommended that they consume (400 ug/day) of folate as supplements or fortified foods in addition to folate containing foods.Folate requirement

52. Folate DeficiencyFolic acid deficiency is probably the most common vitamin deficiencyObserved primarily in the pregnant women, in both developed and developing countries.The pregnant women, lactating women, and women on oral contraceptives are also susceptible to folate deficiency.

53. Folate DeficiencyDeficiency symptomMegaloblastic Anemiadecreased DNA synthesisfailure of bone marrow cells to dividenormal protein synthesisresults in large immature RBC’scontrast with microcytic hypochromic anemia

54. Folate and Birth DefectsAdequate intakes of folate during pregnancy can reduce a woman’s chances of having a child with a neural tube defect (NTD). World prevalence: 400,000 live births with NTDs/yrNTD arise in the first days or weeks of pregnancy, long before most women suspect they are pregnant. Defects in formation of neural tube (brain & spinal cord)

55. Panthothenic acid (Greek : Pantos-everywhere) formerly known as chick anti – dermatitis factor. Its metabolic role as Coenzyme A is also widespread.The function of pantothenic acid are exerted through coenzyme A or CoA ( A for acetylation) .Coenzyme A is a central molecule involved in all the metabolism (carbohydrate, lipid and protein).It play a unique role in integrating various metabolism pathways.More than 70 enzymes that depend on coenzyme A are known.Pantothenic Acid

56. The burning feet syndrome pain and numbness in the toes, sleeplessness, fatigue, neuromuscular degeneration and adrenocortical insufficiency.Pantothenic Deficiency

57. Vitamin C (ascorbic acid)

58. Functions of Vitamin CEnhances absorption of ironCollagen FormationBile acid synthesisAntioxidant Activity

59. Vitamin C Deficiency Deficiency: called scurvyMost scurvy symptoms are due to collagen breakdownLoss of appetiteGrowth cessationBleeding gumsSwollen ankles and wristshemorrhages in the skin, muscle &bone↓wound healing AnemiaRed spots on skinWeaknesslow resistance to infections