Alcohol in the Body

Alcohol in the Body

• Alcohol, for chemists, is a class of organic compounds containing hydroxyl groups (e.g., glycerol).
• For most people, alcohol refers to the intoxicating ingredient in beer, wine, and liquor (ethyl alcohol or ethanol).
• Alcohols act as lipid solvents, dissolving lipids from cell membranes, destroying cell structures.
• Ethanol is less toxic than other alcohols when diluted and taken in small doses.
• Alcohol acts as a drug, modifying body functions, offering benefits and hazards.
• The Dietary Guidelines for Americans advise that alcohol, if consumed, should be done in moderation.

How many drinks constitute moderate use, and how much is "a drink"?

• A "drink" is defined as: one glass of wine, two beers, a drink with 1/2 ounce of pure ethanol, or one "shot" of 80 proof (40%) whiskey.
• These standard measures all contain the same amount of pure alcohol (1/2 ounce or 30 mL).

Moderation

• Individual tolerances for alcohol vary, making a one-size-fits-all daily amount impossible.
• Healthy individuals can consume up to 2 drinks/day for men and 1 drink/day for women (maximum, not average).
• The amount of alcohol a person can safely consume varies because it depends on genetics, health, gender, body composition, age, and family history.

Alcohol in the GI Tract

• Alcohol is quickly absorbed across the walls of an empty stomach, while a full stomach delays absorption.
• The stomach begins to break alcohol down using alcohol dehydrogenase.
• Women typically produce less alcohol dehydrogenase than men, resulting in more alcohol reaching the intestine for absorption.
• Alcohol is rapidly absorbed in the small intestine.
• Alcohol is given priority for treatment via absorption and metabolism before other nutrients. This ensures speedy disposal because it cannot be stored in the body and is potentially toxic.

Alcohol in the Liver

• Liver cells are the first to receive alcohol-laden blood.
• They are the only cells in the body capable of producing enough alcohol dehydrogenase to oxidize alcohol at an appreciable rate.
• The routing of blood through liver cells allows them to dispose of alcohol before it moves on.
• Alcohol disrupts normal liver activity.
• Liver cells normally utilize fatty acids as their primary fuel and package them as triglycerides.
• If alcohol is present, liver cells preferentially metabolize it, causing fatty acids to accumulate, potentially damaging liver structure, and impeding fat metabolism in the process.
• The amount of alcohol a liver can process depends on body size, previous drinking experience, food intake, and overall health. The maximum digestion rate is roughly 1/2 ounce of ethanol per hour.
• Excess alcohol over the liver's processing capacity circulates through the body until the enzymes have capacity.
• Alcohol dehydrogenase levels vary between individuals which may be hereditary or determined by recent food intake.
• The liver degrades proteins, including the alcohol-processing enzymes, which reduces its alcohol metabolism rate, as little as one day of fasting. This means that drinking after a period of not eating leads to faster and more pronounced effects.

Alcohol Metabolism

• Alcohol dehydrogenase oxidizes alcohol to acetaldehyde, a highly reactive toxic compound.
• High acetaldehyde concentrations in the brain and other tissues damage the body's systems, having far-reaching implications.
• Acetaldehyde dehydrogenase then converts acetaldehyde to acetate, which is further converted to acetyl CoA (crucial for metabolic processes).
• Alcohol metabolism's priority status is to ensure speedy removal and reflects that alcohol cannot be stored in the body and is potentially toxic.
• The niacin coenzyme is essential in various bodily metabolic processes; however, alcohol consumption leads to a slowdown.

Effects on the Liver

• Alcohol exposure accelerates fatty acid synthesis, leading to fatty liver—the first stage of liver deterioration.
• This interferes with nutrient and oxygen distribution to liver cells, but is reversible with abstinence.
• Continued fatty liver can lead to fibrosis, where liver cells die, forming fibrous scar tissue.
• Liver cell regeneration is possible with proper nutrition and abstinence, but cirrhosis (the advanced stage), represents the least reversible damage.

Alcohol Metabolism (Liver)

• The liver possesses an enzyme system (MEOS) that handles about one-fifth of a person's total alcohol consumption, metabolizing alcohol and various drugs.
• Alcohol stimulates enzyme production in MEOS leading to enhanced alcohol metabolism and tolerance.
• Alcohol competes with other drugs, altering their metabolism and making dosage determination difficult in users.

Alcohol Disposal

• Alcohol is primarily metabolized by the liver, but a 10% portion is cleared through the breath and urine.
• Breath and urine tests are used to determine blood alcohol concentration.
• Legal drunkenness varies across states; 0.08% blood alcohol concentration or less is generally the legal limit.

Effects on the Brain

• Alcohol is a narcotic, historically used as an anesthetic but lacking predictable effectiveness in dosage.
• Alcohol's sedation of inhibitory nerves overrules the excitatory ones, making the central nervous system a depressant, impacting all nerve cells.
• Alcohol affects judgment and reasoning centers in the frontal lobe, speech and vision centers in the midbrain, then voluntary muscular control in the cerebellum, ultimately affecting respiration and the heart with higher levels. Alcohol is a fatal dose if it reaches all brain centers.

Alcohol Blood Levels and Brain Responses

• Alcohol blood concentration varies with several factors, including dose, consumption rate, gender, and body weight.
• Various impacts on brain and bodily functions occur in tandem and are dependent on the concentration.
• Lethargy, slowed reflexes, slurred speech, impaired coordination, poor judgment, and loss of consciousness are all possible consequences of excessive alcohol consumption.

Dehydration

• Alcohol consumption can increase urination, as alcohol suppresses antidiuretic hormone (ADH) production, causing water loss.
• The body's water loss leads to thirst and increased alcohol consumption, worsening dehydration.
• Drinking water when thirsty and before and after alcoholic drinks can counteract this.

Malnutrition and Weight

• Alcohol often replaces meals in heavy drinkers, leading to malnutrition.
• It provides calories but lacks essential nutrients.
• Alcohol consumption contributes to body fat and central obesity.

Effect of Alcohol on Nutrient Metabolism

• Chronic alcohol abuse impairs nutrient metabolism and displaces nutrients from the diet.
• Most significantly impaired is folate (B9), affecting liver function and kidney excretion, impacting cell regeneration and potentially resulting in colorectal cancer.
• Alcohol disrupts homocysteine conversion to methionine, resulting in excess homocysteine—an adverse factor associated with heart disease.
• Alcohol also directly affects nutritional absorption and causes digestive system inflammation.

Signs of Alcoholism

• Tolerance: needing higher doses of alcohol to achieve intoxication.
• Withdrawal: experiencing anxiety, tremors, increased heart rate, and more upon cessation or significant reduction in alcohol intake.
• Impaired control: repeatedly failing to control drinking despite negative consequences.
• Disinterest: neglecting responsibilities and obligations for alcohol.
• Time: devoting an excessive amount of time obtaining, consuming, or recovering from drinking.
• Cravings, impaired abilities, and problems despite these negative indicators are also signs of potential problems.

Health Effects of Heavy Alcohol Consumption

• Alcohol increases the risk of many health problems, including but not limited to arthritis, bone loss, cancer (various types), fetal alcohol syndrome, heart disease, hyperglycemia and hypoglycemia, nerve disorders, obesity and psychological issues.

Coffee

• Coffee originated in northeast Africa, traveling through the Middle East and to Europe over the last 1200 years.
• Today, coffee is the second-most valuable commodity behind oil.
• It's commonly consumed globally, particularly in Europe and the United States (around 5.1kg/year and similar in the US).
• Coffee's alerting effect on the human brain has driven a desire to better understand its effects on the body.
• Some individuals are intolerant to coffee, experiencing irregular heartbeat or headaches—potential signs of individual variation.

Coffee Composition

• Coffee is a complex mixture of chemicals and caffeine, which is the primary source in many populations.
• It contains thousands of chemicals, including carbohydrates, lipids, nitrogenous compounds, vitamins, minerals, alkaloids, and phenolic compounds.
• The content of caffeine in a prepared cup can vary from 30mg to 175mg, depending on preparation.

Caffeine's Impact

• Caffeine is a psychoactive drug, interacting primarily through the antagonism of adenosine receptors.
• Adenosine is tied to drowsiness, so caffeine's action increases alertness in the central nervous system.

Coffee and Antioxidants

• Coffee is a significant source of antioxidants, particularly chlorogenic acid.
• Antioxidant activity varies by roast level, with maximum antioxidant activity commonly found in medium-roasted coffee.
• Diterpenes in unfiltered coffee are linked to increased cholesterol levels, but filtered coffee's impact is minimal.

Health Effects of Coffee

• Many studies link moderate coffee consumption to a lower risk of several chronic diseases like type 2 diabetes, certain kinds of liver damage, and Parkinson's disease.
• It may improve endurance during prolonged physical activity, and some evidence suggests a link to a reduced risk of cancer.

Negative Health Effects of Coffee

• Caffeine can have moderate effects on the cardiovascular system (e.g., high blood pressure, tachycardia, arrhythmia).
• It can decrease calcium absorption.
• Excessive caffeine intake during pregnancy has potential detrimental effects on the developing fetus.
• Excessive consumption may cause anxiety, nervousness, and other symptoms in children.

This quiz explores the chemical nature of alcohol, its effects on the body, and guidelines for moderate consumption. Participants will learn about the different types of alcohol, standard drink definitions, and the health implications of alcohol use. Test your knowledge on how alcohol interacts with human physiology.