Alcohol

Alcohol and Alcohol Production

• Chemically known as ethanol
• Provides 7 kcal/g
• Absorbed by simple diffusion
• Product of fermentation
  • Carbohydrates (mono and disaccharides) encourage growth of yeast
  • Yeast convert pyruvate (product of glycolysis) into alcohol and carbon dioxide
  • If starches used then starches such as barley are “malted” to produce simple carbohydrates
  • Beer is produced using malting cereal grain
  • Wine is produced by fermenting grapes
  • Distilled spirits are produced by fermenting organic (plant material) then separate the liquid products of fermentation
• Alcohol been in production for 10,000 years and 4,000 for beer!

Alcohol Metabolism

• Alcohol is readily absorbed into the blood and depends on gastric emptying
• It is distributed widely over body in fluid compartments
• Moves easily through cell membranes and damages cell membrane proteins as it diffuses
• Most damaging effects found in liver due to alcohol oxidation
• Metabolism of alcohol dependent on many factor
  • Gender, race, size, physical condition, what is eaten, alcohol content of beverage, and amount of sleep had
  • Ability to produce alcohol dehydrogenase (ADH) – an enzyme that metabolizes alcohol
  • Men metabolize 30% and women metabolize 10% of the alcohol ingested
  • Women develop alcohol related ailments more readily
• Alcohol metabolized primarily by the liver but alcohol can be excreted by the lungs
• Alcohol content of expired air has a constant relationship to the blood alcohol concentration
• Blood alcohol concentration
  • 0.08% - 0.10% considered legally drunk
  • 0.35% - 0.50% alcohol poisoning
  • > 0.50% coma or death
• Liver has three pathways of alcohol metabolism:
  • Alcohol dehydrogenase
    • Uses NAD to convert toxic alcohol into non-toxic metabolite acetaldehyde
    • Primary method of alcohol metabolism
    • Occurs in cytosol of liver cells
      
  • Microsomal ethanol oxidizing system (MEOS)
    • Uses oxygen and NADP to convert alcohol into acetaldehyde
    • Alternative pathway of alcohol metabolism and increases after chronic exposure to alcohol
    • Occurs in microsomes of liver cells
      
  • Catalase
    
  • Minor patheway for alcohol oxidation
    
  • Breaks down alcohol in the presence of hydrogen peroxie
  • Ocurs in peroxisomes of liver cells

Alcohol Benefits and Problems

• Benefits
  • One drink daily – one 12 ounce bottle of beer or wine cooler, one 5 ounce glass of wine, 3 ounces of sherry or liqueur, or 1.5 ounces of 80 proof distilled spirits
  • Decreased risk of coronary heart disease and ischemic stroke
  • May protect stomach from harmful bacteria
• Problems
  • Alcoholism
    • May interfere with nutrient intake
    • Can cause protein  and energy deficiencies
    • May lead to vitamin and mineral deficiencies
      • Example thiamine deficiency
        • Polyneuropathy (peripheral nerves malfunction)
        • Wernicke-Korsakoff syndrome
          • Wernike (acute phase)- mental confusion, vision impairment, and stupor
          • Korsakoff (chronic phase) - alcohol induced thiamine deficiency; amnesia, confabulation, attention deficit, disorientation, and vision impairment
  • Increases 5 of the 10 leading causes of death in the U.S. – heart disease, certain forms of cancer, cirrhosis of the liver, motor vehicle and other accidents, and suicides
  • No nutritional value
  • Produce cirrhosis of liver
  • Toxicity to fetus (Fetal alcohol syndrome)
  • Brain Damage
  • Carcinogenic effect
  • Hypertension
  • Myocardial depression; arrythmias; cardiomyopathy
  • Cause many social problems
    • Drinking at workplace
    • Failure to operate motor vehicles and other equipment
    • STDs
    • Unplanned pregnancy
    • Affect family especially children