vitamines. lec 1 .2 .pdf

Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry The Ministry of Higher Education and Scientific Research AL-Ameen University Learning package In field of Biochemistry...

Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry The Ministry of Higher Education and Scientific Research AL-Ameen University Learning package In field of Biochemistry Presented to the 2st class students Of Collage of dentistry Designed by Dr.Elham Mudallal Aamer 2024/2025 1  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry Biochemistry Biochemistry: Is the study of chemical processes occurring in living tissues (change in material & energy). Biochemistry: The chemistry which study the molecular structure and function of organic compounds in living organisms (plants, insects, fish, birds, mammals and human beings). -The aim of biochemistry: Is to describe and explain all chemical processes of living organisms and their interactions with their environments both in health and disease condition. -These molecules include the six major compounds: 1- Carbohydrates 2- Protein 3- Fat (lipid) 4- Vitamins 5- Mineral 6- Water 2  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry -Human bodies consist of 65% H2O, 35% :1-organic compound including: A-Non – nitrogenous : 1. Lipids 2. Carbohydrates 3. Lactic 4. Glycerol B-Nitrogenous: 1. Proteins 2. Some lipids 3. Urea 4. Creatinine 5. Amino carbohydrates 6. Purine, Pyrimidine..etc. 2-Non-organic compound: 1-Salts 2. Free O2 3. Ammonia 4.Water. 3  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry Vitamins 1-Central ideas: 1-1: General view and definition of vitamins. 1-2: Classification of vitamins. 1-3: Properties of water-soluble vitamins. 1-4: Properties of fat-soluble vitamins. 1-5:Clinical significance 2: Performance Objectives: After studying this modular unit, you should be able to: 2.1. Define vitamin. 2.2 Classification of vitamins. 2.3. Enumerate clinical significance &daily need of each vitamin. 4  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry Vitamins Human nutrition consists of primary nutrients (carbohydrates, proteins and fats); in addition to this ,food should contain othere ssential substances which the body is unable to produce by transforming from other components. Such components include essential amino acids, essential fatty acids, mineral compounds and vitamins. - Vitamins definition : - Vitamins: Are organic compounds that function in a wide variety of capacities within the body. The most prominent function is as cofactors for enzymatic reactions. they generally cannot be synthesized by cells and must be supplied in the diet. -Biological importance : 1. Vitamins are essential for growth, maintenance and reproduction. 2. Do NOT yield energy when broken down. 3. Fat soluble vitamins are required for normal vision, blood clotting, bone formation and maintenance of membrane structure. 5  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 4. Most of the water soluble vitamins function as coenzymes or prosthetic groups of several enzymes involved in carbohydrate, lipid and amino acid metabolism etc. 5. Vitamins A and D act as steroid hormones. Vitamins differ from hormones in: 1-They are not produced within the organism. 2-Most of the vitamins have to be provided in the diet. -Excretion and storage: Excess hydrophilic vitamins taken from food are usually excreted quickly in urine from the body (with the exception of vitamin B12). On the other hand, fat-soluble vitamins may deposit in the body for a longer time: vitamins A and D, and vitamin K to a limited extent in the liver, and tocopherol in the adipose tissue. Toxicity manifestations (sometimes referred to as hypervitaminosis) Can only be found in vitamins A and D. They almost always occur as a consequence of wrong dosage for therapeutic use. 6  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 2. Classification of vitamins: All vitamins are broadly divided into two groups according to solubility. A-Water - Soluble Vitamins B-Fat - Soluble Vitamins. A-Water - Soluble Vitamins: The general characters: 1-Polar (soluble in water) 2-Easy absorbed 3-Not stored except B12 in liver. 4-Excreted in urine. The types of water - Soluble Vitamins : 1-Vitamin B1 (Thiamin):. Stable at cooking Lost in boiling process. Sources: cereal , egg yolk ,yeast , bread, rice, liver and milk. The dietary need from 1.0 - 1.5 mg/day for normal adults. Clinical sig. Beriberi (loss of appetite) 7  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 2-Vitamin B2 (Riboflavin): Functions: Has very important role in protein , carbohydrate and lipid metabolism Sources: eggs, milk, meat. The normal daily need: 1.2 - 1.7 mg/day for normal adults. Riboflavin decomposes when exposed to visible light. Clinical sig. 1-Cheilosis, 2-Weakness of the legs. 3-Vitamin B6 (pyridoxine): Found in liver, yeast, egg yolk, meat& cereals. The requirement from 1.4 - 2.0 mg/day for a normal adult (during pregnancy increases approximately 0.6 mg/day). Clinical sig. some types of anemia & affecting on the nervous system. 8  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 4-Vitamin B12 (Cyanocobalamin) Is complex compound consist from three molecules : ( Cobalt , cyanide and nucleotide) storage in liver. Sources: Vit b12 cannot be synthesis by human body and not fond in plant, so most be taken from animals sources: Liver, meat, fish, kidney ,milk and eggs. - Very important in RBCs formation. Clinical Significance: 1-Pernicious anemia due to autoimmune disease. 2-Bacteria utilized Vit B12 lead to its deficiency. 3- Malabsorption due to small intestine diseases. 9  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 5-Folic Acid: -Like B12 is very important in RBCs formation. Sources: - leafy vegetables as well as animal liver. Clinical Significance :- Folate deficiencies are rare due to the presence of folate in food but under condition of antibiotic therapy deficiency occur. But cause megaloblastic anemia. Daily requirements = 300 – 500 micrograms (intestinal microorganism several times the amount ) 6-Vitamin C (Ascorbic Acid): Sources ;- Fresh green vegetables , citrus fruits Effected by temperature. Deficiency in vitamin C leads to the disease scurvy.(Scurvy is occur duo to inadequate daily intake vitamin C. characterized by easily bruised skin, muscle fatigue, soft swollen gums, decreased wound healing and hemorrhaging) Daily need 30 mg -70 mg (more that in pregnancy) 10  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry B- Fat - Soluble Vit.: Include A , D , E , K. 1-Not Polar (soluble in fat). 2-Need fat to absorbed 3-Stored in body after absorption : A,D and K stored in liver while E in adipose tissue. 4-Not excreted in urine but may be excreted in bile and appear in urine. 5- Some kinds can be synthesized inside the body 6-They are transported in the blood, in lipoproteins or attached to specific binding proteins. 7-Stable to normal cooking conditions. 11  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry -The types of fat soluble vitamins: 1.Vitamin A (retinol) 2 Vitamin E (α-tocopherol) 3 Vitamin D (calciferol) 4 Vitamin K (2-methyl-1,4-naphthoquinone) 1-Vitamin A: (Retinol) The vitamin play important role in vision: the mechanism of through which vitamin A functions in visual system as Wald’s visual cycle. Vitamin A plays significant role in the photo-chemical phase of this process. -Two forms of vitamin A are present: A1 and A2. - Sources: 1-Animals products : fish, liver, oil, eggs, cheese, meats, milk, cream( A1) 2- plants products: potato ,spinach ,carrots (A2) -Deficiency of the vitamin occurs only after prolonged lack of dietary intake. -Destroyed by cooking & sun drying. - Vitamin A is weak antioxidant. -Vitamin A is stored in the liver. 12  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry - Clinical Significances; - 1- Night blindness. Vitamin A deficiency associated with poor vision in dim light 2- Keratomelacia. 3- Exophthalmia. -Daily needs: 300-750 μg -Toxicity(-Hypervitaminosis): High doses of vitamin A may be obtained from excessive ingestion of vitamin supplements or large amounts of liver or fish oils, which are rich in vitamin A. 2-Vitamin E: (α-tocopherol) Sources: Vegetable oils ,corn oil & wheat oil, liver, fish and meat. -Daily needs 30 I.U. Vitamin E natural antioxidant. Clinical sig. the deficiency accrue due to malabsorption 1-An increase in red blood cell fragility. 2- Muscular dystrophy. 13  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 3-Vitamin D: (calciferol) Vitamin D is a steroid hormone. Sources ;- Egg yolk , milk & fish oil Daily needs 200-400 I.U Functions : 1- Increased and regulate of calcium and phosphate absorption from small intestine to the blood. 2- Inhibiter calcium and phosphate excretion in the blood 3- Mineralization of bones (calcification of bones) Clinical Significance: 1. Vitamin D deficiency in children causes rickets. 2. Vitamin D deficiency in adults causes osteomalacia. -(Hypervitminosis D:) lead to hypercalcemia. Factors affecting on Vit. D level:- 1. Deficiency of calcium & phosphate. 2. Lack of sun-light. 3. Parathyroid gland hormones. 4-Inadequate food rich with Vit D. 14  Dr.Elham M.A Phd Pathological Analysis..Biochemistry \ Dentistry 4-Vitamin K: (2-methyl-1,4-naphthoquinone) (coagulation vitamin): There are two forms :K1 and K2 A-K1 :Found in green vegetables animals ,eggs and liver. B- K2: Produced by intestinal bacteria.(large intestine). -Maintenance levels of blood clotting proteins. -Naturally vitamin K absorbed from the intestines only in the presence of bile salts and other lipids through interaction with chylomicrons. Clinical significance: -In infants :The intestine of newborn infants is sterile, so vitamin K deficiency in infants is possible. -Deficiency in adults is rare accrue due to : a- Malabsorption. b- Antibiotic treatment can lead to deficiency in adults lead to reduced normal flora.in intestine.. ----------------------------------------------------------------------------- 15