Read the summary and the most important questions on food components and health

• Lipids

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• How is dietary fat is digested and absorbed?

  digestion involves breakdown of triglycerides to fatty acids

• What is  the basic chemical structure of the different types of fat (TG, cholesterol, phospholipid)

  Tryglycerides/triacylglycerols: consist of three fatty acids linked via a glycerol molecule
  
  Phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline. They have a polar side and an apolar side. This property is referred to as amphipathic

• Chemistry of lipids

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• Triglycerides are also referred to as triacylglycerols. Triglycerides are fats if they are solid at room temperature and oils if they are liquid at room temperature. What is the basic chemical structure of a triglyceride?

   Triglycerides consist of three fatty acids linked via a glycerol molecule.

•  Triglycerides consist of three fatty acids linked via a glycerol molecule. What is a fatty acid? And the fatty acids that are part of the triglyceride molecule differ in three major properties. What are those properties?

  Fatty acid =  a chain of hydrogenated carbon atoms connected to a Carboxyl Group.
  
  1. chain length
  2. degree of unsaturation, which means the number of double bonds. 
  

  • Unsaturated fatty acids have at least one double bond.
  • Now mono-unsaturated fatty acids have one double bond,
  • whereas poly-unsaturated fatty acids have at least two double bonds.

  3.point of unsaturation which describes where the double bonds are located in the fatty acid molecule.

• What is the nomenclature of the fatty acids and what are the two different nomenclature systems?

  • n or omega designation
  • delta designation

  
  both systems denote the carbon chain length, followed by the number of double bonds
  
  
  position of the double bonds:
  
  

  • the n or omega designation counts from the methylene and only indicates the position of the first double bond. 
  • So for instance n-6 or omega-6 means that the first double bond starts after 6 carbons, counting from the methylene and the next double bond will be positioned three carbons down.

  • delta designation and counts from the carboxylene and indicates the position of all double bonds.

• What are the main fatty acids in our diet? And what are 5 common fatty acids in our diet?

  Oleic and palmitic acid are the most abundant fatty acids in our food supply.
  
  5 common fatty acids in our diet:
  

  • palmitic acid  (c16:0)
  • tearic acid is (c18:0)
  • oleic acid (c18:1)
    
  • linoleic acid c18:2
    
  • linolenic acid (c18:3)
    

• That the firmness of the fat - whether it’s liquid or solid -is determined by?

  1. The types of fatty acids attached to the glycerol molecule.
  

  • The shorter the fatty acids attached, the lower the melting point of the fat
  • Low melting point means that the fat will be liquid at room temperature.
  • The more unsaturated the fatty acids that are attached, the lower the melting point.
    
  • Triglycerides composed of unsaturated fatty acids are therefore liquid at room temperature.
    

• Fat tissue

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• Now what is body fat?

  Fat tissue is composed of fat cells or adipocytes and these are very peculiar cells. Their main feature is a very large lipid droplet.
  Now in addition it contains the nuclei, mitochondria. But they are very much pushed to the outside. So it is a very efficient energy storage cell in the body.

• How does fat get stored in adipose tissue?

  1. consumption of a fatty meal
  2. processed in your GI tract
  3. put into specialized particles called chylomicrons
  4. these chylomicrons deliver the fat throughout your body.
  5. it mainly goes towards two organs: the muscle and the fat tissue.
  6. these two organs are characterized by the presence of a certain enzyme called lipoprotein lipase.
  7. lipoprotein lipase breaks down the triglycerides in the chylomicrons, allowing the fat to be taken up into these tissues.
  8. the activity of lipoprotein lipase dictates where the fat is going,

• What are the different functions of adipose tissue?

  • Heat insulator or cold insulator  (may be important for animals, but not for us)
  • is as an energy storage depot: when we eat too much energy, the excess is stored in the fat tissue.
    
  • endocrine function of adipose tissue: the ability of adipose tissue to produce hormones