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Vitamin & Mineral Deficiency

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Vitamin & Mineral Deficiency

  2. 2.  Thirteen vitamins are necessary for health  Vitamins A, D, E, and K are fat-soluble, and all others are water-soluble
  3. 3.  The distinction between fat- and water- soluble vitamins is important.  Fat-soluble vitamins are more readily stored in the body, but they may be poorly absorbed in fat malabsorption disorders
  4. 4.  A deficiency of vitamins may be  primary (dietary in origin) or  secondary because of disturbances in intestinal absorption, transport in the blood, tissue storage, or metabolic conversion
  5. 5. Vitamin A  Vitamin A is the name given to a group of related compounds  retinol (vitamin A alcohol),  retinal (vitamin A aldehyde),  retinoic acid (vitamin A acid)  The generic term retinoids encompasses vitamin A in its various forms and both natural and synthetic chemicals that are structurally related to vitamin A
  6. 6. Functions of vitamin A  Maintenance of normal vision  Cell growth and differentiation  Metabolic effects of retinoids  Host resistance to infections
  7. 7. Vitamin A Deficiency  Earliest manifestations of vitamin A deficiency is impaired vision, particularly in reduced light (night blindness).  Persistent deficiency gives rise to a series of changes involving epithelial metaplasia and keratinization.
  8. 8.  The most devastating changes occur in the eyes and are referred to as xerophthalmia (dry eye).  First, xerosis conjunctivae  Buildup of keratin debris in small opaque plaques (Bitot spots) and, eventually,  Erosion of the roughened corneal surface with softening and destruction of the cornea (keratomalacia) and total blindness.
  9. 9.  Epithelium lining the upper respiratory passage and urinary tract is replaced by keratinizing squamous cells (squamous metaplasia)  Another very serious consequence is immune deficiency
  10. 10.  Vitamin A Toxicity  Acute  Chronic  Well-established teratogenic effects of retinoids – contraindicated in pregnancy
  11. 11. Vitamin D  Major function of the fat-soluble vitamin D is the maintenance of adequate plasma levels of calcium and phosphorus  Metabolic functions,  Bone mineralization, and  Neuromuscular transmission
  12. 12.  Rickets (in children whose epiphyses have not already closed)  Osteomalacia (in adults), and  Hypocalcemic tetany [Extracellular concentration of ionized calcium, which is required for normal neural excitation and the relaxation of muscles]
  13. 13.  Normal reference range for circulating 25- (OH)-D is 20 to 100 ng/mL;  concentrations of less than 20 ng/mL constitute vitamin D deficiency  Causes  Diet deficiency  Limited exposure to sunlight  Renal disorder
  14. 14. Morphology.  Basic derangement in both rickets and osteomalacia is an excess of unmineralized matrix
  15. 15. Rickets  Most common during the first year of life.  The gross skeletal changes depend on  the severity and duration of the process  the stresses to which individual bones are subjected.
  16. 16.  During the nonambulatory stage of infancy, the head and chest sustain the greatest stresses.  Craniotabes  Frontal bossing and a squared appearance to the head  Rachitic rosary  Pigeon breast deformity
  17. 17.  Ambulating child deformities are likely to affect the spine, pelvis, and tibia lumbar lordosis and bowing of the legs
  18. 18.  In adults, the lack of vitamin D deranges the normal bone remodeling that occurs throughout life.  Production the excess of persistent osteoid that is characteristic of osteomalacia.  Bone is weak and vulnerable to gross fractures or microfractures, which are most likely to affect vertebral bodies and femoral necks.
  19. 19. Non-Skeletal Effects of Vitamin D  Effective against infection by Mycobacterium tuberculosis (stimulates the synthesis of cathelicidin, an antimicrobial peptide from the defensin family)  Innate and adaptive immunity  Gene expression (>200 genes)  Ca colon, prostrate, breast
  20. 20. Vitamin C (Ascorbic Acid)  Scurvy, characterized principally by  bone disease in growing children and  by hemorrhages and healing defects in both children and adults  Vitamin C is present in milk and some animal products (liver, fish) and is abundant in a variety of fruits and vegetables
  21. 21. Function  Best-established function of vitamin C is the activation of prolyl and lysyl hydroxylases from inactive precursors, providing for hydroxylation of procollagen  Collagen, which normally has the highest content, of hydroxyproline, particularly in blood vessels, accounts for the predisposition to hemorrhages in scurvy
  22. 22.  Antioxidant properties  scavenge free radicals directly and  Act indirectly by regenerating the antioxidant form of vitamin E