Vitamins
Gastroenterology physiology
Fat soluble (A, D, E, K)
Fat soluble (A, D, E, K)
- A: Retinol/betacarotene
- Deficiency: epithelial degeneration (skin/lung/GUT/GIT), night blindness
- D: Cholecalciferiol (D3 skin UVB + food/sup), ergocalciferol (D2 sup)
- Rickets/osteomalacia
- E: Tocopherol
- deficiency: cerebellar or posterior column disfunction, haemolysis
- K:
- Bleeding
- B1: Thiamine
- Deficiency: Wet/dry beriberi, Wernicke's
- B2: Riboflavin
- B3: Niacin
- B5: Pantothenic acid
- B6: Pyridoxine
- B7: Biotin
- Deficiency: pale or grey skin, cracked sore tongue, depression, hallucinations, abnormal heart actions, loss of appetite, nausea, dry skin and scaly dermatitis, hair loss, muscle pain, and weakness and fatigue
- B9: Folate (in nature), folic acid (synthetic form):
- Deficiency: megoblastic anaemia, birth defects
- B12 (cobalamin): megablastic anaemia
- transcobalamin I in saliva bind B12 to protect it from low pH
- gastric intrinsic factor released from parietal cells in stomach
- pancreatic proteases in duodenum cleave B12 from TCI, it binds GIF
- absorbed into terminal ileal enterocytes, dissociated and associates with transcobalamin II for transport in blood
- Stored in TCI and TCIII so B12 levels normal in TCII def
- Deficiency:
- Neuro (can happen without megoblasts): Sub acute combine degeneration: irritability, developmental delay/regression, sensory deficits, hypotonia, sz
- Anaemia: pallor, weakness, fatigue, failure to thrive
- glossitis, vomiting, diarrhea, and icterus
- Shilling test investigates the cause: ?diet ?intrinsic factor ?pancreatic ?bacterial overgrowth
- B12 part of enzymes, def can cause methylmalonic acidauria, homocystinuria
- C: ascorbic acid