1Vitamin - D (antirachitic vitamin)       BY         R.PARTHSARATHY
2    Introduction   Vitamin D is a steroid.   It is present in animals, plants and yeast.   Insoluble in water, soluble...
3Chemical structureMOST IMPORTANT FORMIt is considered asprohormone.BECAUSEFrom which1,25-dehydrocholesterolsynthesized. (...
4Metabolism
5Sources   Liver and viscera of fish.   Liver of animals which feeds on fish.   Eggs, butter and milk. But the cheapes...
6    Functions   Vitamin D acts on organs such as bone, kidneys, intestinal    mucosa for regulation of calcium and phosp...
7Functions
8Daily requirements   Children and infants : 400IU/day   Adults               : 200IU/day   Plasma concentration of 25-...
9       Deficiency manifestations   Deficiency of vitamin D produces rickets in growing children    with characteristic d...
10Deficiency manifestations    Pigeon’s chest    Bowed legs
11Toxicity   Vitamin D is fat soluble, and accumulation (from diet) in    the body can be toxic.   The long-term safe do...
12    Hyper-vitaminosis   Excess of vitamin D causes toxicity characterized by        Nausea        Anorexia        Diges...
13    Factors that influence    vitamin D status   Genetics       Vitamin D resistant rickets (hypophosphatemic rickets)...
14Thank you
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Vitamin-D

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Vitamin-D

  1. 1. 1Vitamin - D (antirachitic vitamin) BY R.PARTHSARATHY
  2. 2. 2 Introduction Vitamin D is a steroid. It is present in animals, plants and yeast. Insoluble in water, soluble in fat and organic solutions. Sensitive to oxygen, light and iodine. Heating and mild acidity can convert into inactive form.
  3. 3. 3Chemical structureMOST IMPORTANT FORMIt is considered asprohormone.BECAUSEFrom which1,25-dehydrocholesterolsynthesized. (active form)
  4. 4. 4Metabolism
  5. 5. 5Sources Liver and viscera of fish. Liver of animals which feeds on fish. Eggs, butter and milk. But the cheapest is the sunlight.
  6. 6. 6 Functions Vitamin D acts on organs such as bone, kidneys, intestinal mucosa for regulation of calcium and phosphorus metabolism. It promotes intestinal absorption of calcium and phosphorus. It promotes bone resorption and calcium mobilization to increase the levels of calcium and phosphorus.(PTH) Mineralization of bone is promoted by 1,25-dihydroxy D3. It is necessary for the development of bones and normal growth of the body. It also increases the citrate level of blood, bone, kidneys and heart tissues.
  7. 7. 7Functions
  8. 8. 8Daily requirements Children and infants : 400IU/day Adults : 200IU/day Plasma concentration of 25-OH D3 Average 25-30 ng/mL Range 8 - 60 ng/mL Levels < 10 ng/mL indicative of deficiency Levels > 150 ng/mL associated with toxicity
  9. 9. 9 Deficiency manifestations Deficiency of vitamin D produces rickets in growing children with characteristic defects in bone growth. Deficiency of vitamin D in adults is called osteomalacia which is characterized by - poor intestinal absorption of calcium and phosphorus. - rise in urinary phosphorous. - negative calcium balance. - muscular weakness and early fracture of bone. - loss of calcium and bowed legs.
  10. 10. 10Deficiency manifestations Pigeon’s chest Bowed legs
  11. 11. 11Toxicity Vitamin D is fat soluble, and accumulation (from diet) in the body can be toxic. The long-term safe dose of vitamin D is not known, however, 10,000 IU /day is safe in healthy adults All known cases of vitamin D toxicity have involved intake of or over 40,000 IU/day. The LD50 in man is unknown – there are no reported deaths from acute toxicity.
  12. 12. 12 Hyper-vitaminosis Excess of vitamin D causes toxicity characterized by Nausea Anorexia Digestive disturbances and calculi formation. Elfin facies
  13. 13. 13 Factors that influence vitamin D status Genetics  Vitamin D resistant rickets (hypophosphatemic rickets)  Vitamin D dependent rickets (type I)  Vitamin D dependent rickets (type II) Drugs Anticonvulsant drugs such as Diphenylhydatoin, phenobarbital Alcohol  low 25(OH)D level Age  Low epidermal con of 7-dehydrocholesterol  1-hydroxylase: less responsive to PTH Sex
  14. 14. 14Thank you

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