Lecture 31

Vitamins

• Vitamins: This is an organic substance that can not be produced by cells of body but needed in small amounts for normal metabolism
  
• Before we recognized vitamins - tested on animals to see whether they needed them or not
  
• Water soluble vitamins – (two types)
  
  • B vitamins – these are thyamin, riboflavin, folic acid, niacin, pyroxidine, pantothenic acid, biotin, cyanocobylamin (B-12), AND vitamin C (ascorbic acid)
    
    • Primates are only mammals that can not produce ascorbic acid
      
    • All except B-12 are actively absorbed in the small intestine – B-12 – lining of stomach makes intrinsic factor - This mixes with the intrinsic factor and the resulting complex is taken up by the illium
      
    • B-12 is has cobalt in name because it contains cobalt - the role of the element cobalt in metabolism is to be a part of B12 – don't need to take in cobalt
      
    • B12 is stored by the liver – it is the only H20 soluble stored by the liver – other H20 soluble vitamins are not stored by the liver and thus deficiencies can occur – B12 stored for year in liver – thus deficiencies in B12 are rare
      
• Fat soluble vitamins - Come in with rest of the fat – are A, D, E and K
  
  • Lack is not common unless not taking them in– K is not stored by liver – only one not stored of fat ones - Bacteria in stomach makes vit. K and is stored in colon – Only time you really get deficiencies when taking antibiotics
    

Elements

• Na+ cotransport with aminio acids and hexose, and K+ is taken in by solvent drag, Cl taken in by chlorine bicarb exchange
  
• Most elements are taken up in amounts that reach the intestines – exception Ca+, iron (Fe++/+)
  
  • Calcium uptake is regulated by vitamin D – increase amount of binding protein
    
  • The iron is taken up by a variety of mechanism in the cell – taken up by cell where there is a binding protein called apoferitan which will bind with the iron – reversible rxn – if we are taking iron away from this then it will break off (feritan) - Transferren goes around in blood – this seems to stay at 35% sat. if it drops below this it will pick up iron – if above will not – this iron will eventually sucked in to the luman – iron will be lost – iron toxicity is hard
    

Nutrition

• Protein – essential amino acid – this is considered this because they must be consumed available for normal protein metabolism – some can be made – these are non-essential aminio acids – essential ones valine , leucine, lysine, semi essential amino acids – can be generated but not in amounts necessary for growth – histidine, argining – must take in in correct balance
  
  • Need balance –protein is a well balanced protein – eat 100g of protein – body will uptake 100g – perfect balance
    
  • If add addlycine to 100g à 103 g now – only utilize 96 g – this throws balance off thus less absorbed – poorly balanced called biological values – high/low
    
  • Biological value – proteins with high bio value 1- milk or eggs – 2 – meat, 3- soy beans and alphalpha – good source of protein- quality à rice (not good source) and beans (fair quality) together form a good quality protein because the amino acids compliment each other – jello very poor souce of protein
    
  • Ruminents (cows, sheep) – can survive on a very low level of quality protein – this is because none of the protein they eat is absorbed by them – the luman bacteria breaks it down and then rebuilds essential amino acids to a nice balanced protien
    
  • Non-Ruminent herbivois (horses / rabbits) – need higher level of protein – these animals have an extremely large cecum – the only thing the bacteria gets out of the protein is not as good – protein absorption does not occur in cecum or colan – but it can get a lot of energy from its breaking it down to volatile fatty acids – runs on this for energy - feces have high quality bacteria – horses will eat its own feces – newborn fouls eat mothers feces good protein – inoculates GI tract so it can eat grass