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 distillation which separates liquids yielded from 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 alcohol into acetaldehyde
  • Microsomal ethanol oxidizing system (MEOS)
  • Uses oxygen and NADP to convert alcohol into acetaldehyde
  • Catalase – found 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

Chapter Objectives

After reading chapter eight - A student should be able to

  1. Discuss the process of fermentation
  2. List and discuss the factors that effect alcohol metabolism
  3. Describe in detail the following processes: alcohol dehydrogenase, catalase, and microsomal ethanol oxidizing system
  4. List and discuss benefits and problems associated with alcohol consumption