Alcohol in the Body

Alcohol in the Body

• Alcohol, for chemists, is a class of organic compounds containing hydroxyl groups (e.g., glycerol). Commonly, alcohol refers to the intoxicating ingredient in beer, wine, and liquor, chemically known as ethyl alcohol or ethanol.
• Alcohols act as lipid solvents, dissolving lipids from cell membranes. This rapid penetration destroys cell structures, making them effective disinfectants.
• Ethanol is less toxic than other alcohols when sufficiently diluted and consumed in small doses. Alcohol is a drug, modifying body functions, and offers benefits and hazards.
• A "drink" is defined as one glass of wine, two beers, one-half ounce of pure ethanol, or one "shot" of 80-proof (40%) whiskey. One standard drink contains the same amount of pure alcohol.
• Moderate alcohol use is up to two drinks per day for men and one drink per day for women. Individual tolerances vary.
• Alcohol is treated as a substance with special privileges in the body. Its effects on the GI tract, liver, and brain are significant and often observed almost immediately.

Effects of Alcohol on the GI Tract

• When the stomach is full of food, alcohol absorption into the bloodstream slows significantly, reducing its immediate effect on the brain.
• Carbohydrate and high-fat snacks slow alcohol absorption, ensuring it remains in the stomach longer.
• Alcohol absorbs quickly across the empty stomach lining, reaching the brain within minutes. This leads to a faster, more immediate euphoric effect and creates a dependency loop.
• Women typically produce less alcohol dehydrogenase, an enzyme that breaks down alcohol in the stomach. This leads to higher blood alcohol concentrations and faster intoxication rate for women compared to men.
• Alcohol is rapidly absorbed in the small intestine, receiving priority treatment over other nutrients, leading to faster and more significant effects. Alcohol is rapidly metabolized for quick elimination, which reflects its potential toxicity and the lack of storage capability.

Impact of Alcohol on the Liver

• Liver cells are the first to receive alcohol-laden blood.
• The alcohol dehydrogenase enzymes in liver cells are responsible for oxidizing alcohol, but the presence of alcohol can disrupt normal liver activity.
• Alcohol can cause liver cells to focus on metabolizing alcohol, leaving less capacity to process fatty acids. This disruption leads to fatty liver, even when the individual stops drinking.
• The maximum rate of alcohol breakdown in the liver depends on the amount of alcohol dehydrogenase available as well as the individual's body size, past drinking history, current health status, and the quantity of food consumed.
• Excessive alcohol intake can lead to liver damage and can permanently impair its function.

Alcohol Metabolism

• Alcohol is metabolized in the liver through a process that involves the conversion of ethyl alcohol into acetaldehyde, then to acetate, a substance that plays a role in energy metabolism. Alcohol dehydrogenase and acetaldehyde dehydrogenase are the key enzymes in this process.
• The liver's priority treatment of alcohol can impair its handling of drugs and nutrients. The MEOS system plays a significant role in metabolizing alcohol as well as drugs and other substances and its efficiency increases with repeated exposure to alcohol.
• Alcohol's metabolism can interfere with the metabolism of other drugs that the body intakes. The rate at which alcohol is eliminated from the body is much faster than when many other drugs are absorbed.

Alcohol Disposal

• The primary disposal method is through liver metabolism but about 10% also leaves the body through breath and urine. This 10% expulsion rate is the basis for breathalyzer and urine testing.
• Legal limits for blood alcohol content vary by jurisdiction, but are typically set at 0.08% or less.

Effects on the Brain

• Alcohol is a narcotic, sedating inhibitory nerves more effectively than excitatory ones. This results in a depressive effect on the brain.
• Alcohol affects the frontal lobe, impairing judgment. The midbrain's speech and vision centers are also affected.
• Voluntary muscular control can be compromised, and finally, respiration and heart function are impacted. High doses can lead to death because the functions controlling breathing and heartbeat are affected and subdued.

Effects on the Liver

• The synthesis of fatty acids increases with alcohol exposure, leading to fatty liver. This is the first stage of liver deterioration.
• Continued alcohol intake can lead to irreversible liver damage, with the formation of fibrous scar tissue in the liver cells (fibrosis). At the most severe stage, where liver cells are extensively damaged and the liver becomes scarred, the condition is known as cirrhosis.
• Liver cells, unlike brain cells, can regenerate with proper nutrition and abstinence from alcohol.

Dehydration

• Alcohol depresses the production of the antidiuretic hormone (ADH), leading to increased urination.
• Water loss can lead to dehydration, and the urge to drink more alcohol while already dehydrated. Therefore, drinking water when thirsty and before drinking alcohol can help mitigate the negative effects.

Malnutrition/Weight

• Alcohol often replaces meals in heavy drinkers, leading to malnutrition.
• Excessive alcohol consumption provides energy but lacks vital nutrients (e.g., B vitamins).
• Alcohol contributes to central obesity ("beer belly") due to its caloric intake and nutritional deficiency.

Effect of Alcohol on Nutrient Metabolism

• Chronic alcohol abuse hinders nutrient absorption and disrupts the metabolism of numerous nutrients.
• Folate is a critical B vitamin that is severely affected by alcohol, causing its loss in the liver, its increased excretion in the kidneys, and the impairment of its ability to operate properly in the digestive system.
• Folate deficiency can damage liver cells and the small intestine and be linked to liver damage, heart disease and colorectal cancer.
• Alcohol interferes with folate's ability to convert homocysteine into methionine. This imbalanced leads to an excess of homocysteine and an insufficient supply of methionine, negatively impacting cell growth, especially in rapidly dividing tissues. Other B vitamins are also affected.

Signs of Alcoholism

• Tolerance: individuals progressively need more alcohol to feel its effects.
• Withdrawal: symptoms like anxiety and seizures occur when alcohol intake is reduced suddenly.
• Impaired Control: individuals continue drinking despite negative consequences and/or attempts to control their alcohol consumption.
• Disinterest: neglecting relationships, work, or personal responsibilities due to alcohol.
• Time: significant time and effort are spent obtaining or consuming alcohol, or recovering from its effects.
• Cravings, impaired ability, problems.

Health Effects of Heavy Alcohol Consumption

• A multitude of health issues can arise due to heavy alcohol use, affecting various body systems. These include liver damage, cardiovascular diseases, bone loss and numerous types of cancers. Malnutrition is another significant effect of chronic heavy drinking.