BIOMED SCIE LECTURE 8 BMOL10030: Cardiovascular Disease III

• Fatty acids


  The carboxylic acid portion of all biologically derived triglycerides

  
• There are more than 70 known naturally occurring fatty acids

  
• Fatty acids


  • Polar end - carboxylic acid group (Hydrophilic)
  • Non-polar tail - hydrocarbon chain (Hydrophobic)

  
• Fatty acids (by number of double bonds)

  • 18:0
  • 18:1
  • 18:2
  • 18:3

  
• Hydrogenation


  A process that can turn liquid oil into solid fat
• Full hydrogenation


  • Produces waxy fat
• Partial hydrogenation


  • May produce trans fats
• Cis


  Double bonds on the same side
• Trans


  Double bonds on opposite sides
• Trans fats are more symmetrical and allow better packing than cis fats
• Hydrogenation process


  1. Bubbling hydrogen at 250 to 400°C

  2. Vegetable oil + metal catalyst (nickel or platinum)
• Partial hydrogenation


  Produces trans double bonds
• Oleic acid


  A cis unsaturated fatty acid that comprises 55–80% of olive oil

  
• Elaidic acid


  A trans unsaturated fatty acid often found in partially hydrogenated vegetable oils (up to 40% volume)

  
• By the 1960's, 60% of vegetable oil used in food was partially hydrogenated
• Oil rancidity


  Free radicals attack C=C bonds leading to decomposition (hydrolysis or oxidation)
• Products containing hydrogenated vegetable oils have a better shelf-life and can be reused again and again
• Denmark was the first country to ban the use of trans fats in restaurants in 2003
• The World Health Organisation aims to eliminate trans fats from food production by 2023
• 16 countries with highest proportion of coronary heart disease deaths caused by trans fat intake not implementing best-practice policies
• Cholesterol


  A vital component in animal cell membranes, made by the liver and comes from diet
• LDL (Low-density lipoprotein)


  Delivers cholesterol to cells for membrane production, considered 'bad'
• HDL (High-density lipoprotein)


  Scavenges cholesterol for return to the liver, considered 'good'
• Saturated fatty acid


  Increases LDL-C, decreases HDL-C

  
• Unsaturated fatty acid


  Decreases LDL-C, increases HDL-C

  
• Trans fatty acid


  Increases LDL-C, decreases HDL-C

  
• Atherosclerosis


  Damage to the inner lining of an artery and deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances can build up
• Cholesterol build up is caused by too much ('bad') LDL-Cholesterol in the plasma
• Factors that can decrease damage to vessel wall and LDL/HDL ratio


  • Exercise, maintaining 'healthy' BMI
  • Not smoking
  • Normal blood pressure, normal blood sugar
  • Avoiding foods with trans fats, high saturated fat and high cholesterol
• Stanol esters


  Chemicals known to reduce LDL-C in plasma
• 1. 3g of stanol esters per day proven to reduce LDL-C by about 10-15%
• Worldwide, almost 2 billion adults are overweight and 650 million are clinically obese
• In Ireland, 37% of people aged 15 and over are overweight and 23% are obese
• Predicted by 2030 in Ireland: Men 89% overweight / 48% obese, Women 85% overweight / 57% obese
• How obesity occurs


  • Excess calories consumed (food high in saturated/trans fat or carbohydrates) and not used up by physical activity is stored as adipose tissue
• Smokers are twice as likely to have a heart attack as people who have never smoked
• How smoking affects the body

  • Nicotine enhances the influence of adrenaline, increasing blood pressure by constricting blood vessels
  • Carbon monoxide causes endothelial dysfunction
  • Smoking makes platelets more active
  • Smoking decreases HDL (good) cholesterol
• Hyperglycaemia


  Leads to endothelial damage and plaque buildup
• Silent heart attack (silent ischemia)


  Neuropathy and nerve damage leads to a 'numbness', the diabetic does not sense touch, heat, cold or pain, leading to a silent heart attack
• People with diabetes are two to four times more likely to have a heart attack than someone without the disease