Effects of Alcohol on the Body

Introduction

• Ethyl alcohol (ethanol) is the type of alcohol humans ingest.
• Video discussion points:
  • Effects of alcohol on the liver and brain.
  • Symptoms of intoxication or being drunk.
  • Safe amounts of alcohol consumption.

Alcohol Absorption

• Pathway: Esophagus → Stomach → Bloodstream
• Stomach absorption: Small amount absorbed through mucosal lining.
  • Absorption speed depends on stomach contents (faster on an empty stomach).
  • Fat & protein slow absorption and gastric emptying.
• Small Intestine: Major site of alcohol absorption
• Post-absorption: Alcohol travels to the liver via the hepatic portal vein.

Liver Metabolism

• First Conversion: Alcohol → Acetaldehyde
  • Enzyme: Alcohol dehydrogenase
  • Co-factor: NAD
  • Acetaldehyde is more toxic than alcohol.
• Second Conversion: Acetaldehyde → Acetate
  • Enzyme: Aldehyde dehydrogenase
  • Requires NAD, occurs in mitochondria.
• High Levels of Alcohol: Overwhelm liver pathways, leading to potential negative effects
  • Other pathways activated: Microsomal Ethanol Oxidizing System (creates reactive oxygen species) & Peroxisomes (also produce acetaldehyde).

Circulation to Other Organs

• Unmetabolized Alcohol: Circulates through the body, reaches kidneys, sweat glands, lungs.
  • Excreted through breath (basis for breathalyzer tests).

Brain Effects

• Prefrontal Cortex: Inhibits reasoning, thinking, planning, judgment, impulse control (leads to risky behavior).
• Hippocampus: Affects short-term memory, causes blackouts.
• Cerebellum: Impairs movement, balance, coordination (causes stumbling, loss of balance).
• Pituitary Gland: Inhibits anti-diuretic hormone (increases urination, potential dehydration).
• Medulla Oblongata: Suppresses vital life functions (breathing, heart rate, reflexes); high levels can be fatal (alcohol poisoning).

Safe Alcohol Consumption

• General Findings: All science agrees alcohol is toxic.
• Guidelines:
  • 2020-2025 Dietary Guidelines for Americans: No more than 2 drinks/day for males, 1 drink/day for non-pregnant females.
  • Some experts suggest no more than 2 drinks/week for optimal health.
  • Complete abstinence as an option.
• Factors Influencing Safety:
  • Lower safe dose for females (body size, water/fat ratio, alcohol dehydrogenase levels).
  • Zero safe levels for pregnant individuals, those with alcohol use disorder, liver/pancreatic diseases.

Conclusion

• Goal: Provide information for informed decisions on alcohol consumption.
• Potential interests: Effects of caffeine on the brain.