What Alcohol Does to Your Body, Brain & Health

Overview

• Alcohol is one of the most commonly consumed substances on Earth, used for recreational, medicinal, and other purposes.
• Effects of alcohol on our biology range from individual cells to organs and organ systems in our brain and body.
• Inebriation affects thinking and behavior.
• Low to moderate amounts of drinking may or may not be better for health than zero alcohol consumption.
• Severe alcohol intake, binge drinking, and hangovers will be discussed.
• Genetic differences for alcohol and alcoholism will be explored.
• Alcohol consumption in young people can be especially detrimental.

Key Points:

• High levels of alcohol consumption (12–24 drinks per week) can cause neurodegeneration, particularly in the neocortex.
• A recent study found that even low to moderate amounts of alcohol consumption (1–2 drinks per day) can cause thinning of the neocortex and loss of neurons in other brain regions.
• Chronic alcohol intake, even at low levels, can disrupt the brain.
• Maintaining steady blood glucose levels is essential for energy, focus, and overall well-being.
• Getting a good night’s sleep is crucial for mental health, physical health, and performance. Temperature regulation plays a significant role in sleep quality.
  

History of Alcohol Consumption

• Humans have been consuming alcohol for thousands of years 
  • Archaeological evidence from Mesopotamia (5000 years ago)
  • First distillation in China (1^st century)
• Used for nutritional purposes, medicinal purposes, and to change internal state

Chemistry and Biology of Alcohol

• Alcohol is both water-​​soluble and fat-soluble 
  • Can pass into all cells and tissues of the body
• Three main types of alcohol: isopropyl, methyl, and ethyl (ethanol)
  • Only ethanol is fit for human consumption, but still toxic
• Ethanol is converted into acetaldehyde (more toxic) and then into acetate (usable fuel) 
  • Conversion process is metabolically costly and provides empty calories

Effects of Alcohol Consumption

• Regular drinkers or those with a genetic predisposition to alcoholism may feel energized and alert for longer periods when drinking
• Occasional drinkers may experience a brief period of feeling good before transitioning into tiredness and impaired motor function
• Being drunk is a poison-​​induced disruption of neural circuits

• Different effects on individuals can predict predisposition to alcoholism or regular drinking habits
  Effects of Alcohol on the Brain and Body

• Alcohol consumption affects the brain and body in various ways

• Alcohol crosses the blood-​​brain barrier (BBB) and affects neurons and glial cells in the brain
• Prefrontal cortex activity is suppressed, leading to impulsive behavior and less inhibition
• Alcohol affects memory formation and storage, leading to blackouts and forgetting events
• Habitual and impulsive behavior circuits are strengthened with regular alcohol consumption, even if not daily 
  • This can lead to increased impulsivity and habitual behavior even when not drinking
  • Abstinence from alcohol for 2–6 months can reverse these changes in neural circuits
• Food can slow the absorption of alcohol into the bloodstream if consumed before or during alcohol intake 
  • Eating after already being inebriated will not sober a person up but may blunt the effects of additional alcohol consumption

• Alcohol affects serotonin levels in the brain, which are involved in mood and feelings of well-being

  • Serotonin levels are not necessarily associated with depression, but drugs that increase serotonin (e.g., SSRIs) can still be helpful for treating depression
    SSRIs and Depression

• SSRIs can help alleviate depression

  • Not always associated with side effects
  • Dosage is important
• SSRIs likely support relief from depression by changing neural circuits, not necessarily by increasing serotonin itself 
  • Increasing serotonin with SSRIs likely changes neural circuits involved in mood, allowing people to feel better through neuroplasticity

Alcohol and Serotonin

• Alcohol disrupts mood circuitries at first, making them hyperactive 
  • People become talkative and feel good after a few sips of alcohol
• As alcohol wears off, serotonin levels and activity of circuits drop 
  • People feel less good and often consume more alcohol to restore the feeling of well-being

Predisposition to Alcoholism

• Some people have gene variants or are chronic drinkers that make them feel better with increasing amounts of alcohol 
  • These individuals have a higher threshold for alcohol’s sedative effects
  • They may be at a higher risk for developing alcoholism
• Blackout drunk: when people drink and do things while awake but have no recollection of those activities due to the shutdown of neurons in the hippocampus

Alcohol and the Hypothalamic-​​Pituitary-​​Adrenal (HPA) Axis

• Alcohol affects the hypothalamus, which controls primitive functions like rage, sex drive, temperature regulation, appetite, and thirst
• The hypothalamus provides signals to the pituitary gland, which releases hormones into the bloodstream that communicate with the adrenal glands 
  • Adrenal glands release adrenaline (epinephrine) and cortisol, which are involved in stress response

• Regular alcohol consumption can cause changes in the HPA axis, resulting in more cortisol being released at baseline when not drinking

  • This leads to increased stress and anxiety when not consuming alcohol
    Genetic Predisposition to Alcoholism

• Genetic variants can make people more likely to become alcoholics

• Changes in the hypothalamic-​​pituitary-​​adrenal axis can lead to increased alertness with alcohol consumption
• Long-​​term plastic changes in neural and hormone circuitry can result from chronic alcohol consumption 
  • Can lead to less resilience to stress, higher baseline stress, and lower mood overall
• Genes involved in alcoholism are primarily related to serotonin receptors, GABA receptors, and the HPA axis 
  • Combine with environmental factors like social pressures, trauma, and patterns of abuse
• People with low levels of alcohol dehydrogenase may feel sick from alcohol consumption 
  • More common in certain Asian cultures
• Age plays a role in alcoholism 
  • Starting to drink at a younger age greatly increases the risk of developing alcohol dependence
  • Delaying the onset of drinking can reduce the probability of developing alcohol use disorder

Positive Effects of Alcohol

• Documented positive effects of alcohol exist but are few and far between
  Negative Effects of Alcohol on Gut-​​Brain Axis

• Alcohol disrupts gut microbiome

  • Kills healthy gut bacteria
  • Allows bad bacteria to pass from gut to bloodstream
• Alcohol metabolism in the liver is pro-inflammatory 
  • Increases release of inflammatory cytokines (e.g., IL‑6, TNF-alpha)
• Converging effects of disrupted gut bacteria and liver inflammation in the brain 
  • Disrupts neural circuits controlling alcohol intake
  • Leads to increased alcohol consumption
• Especially prevalent in alcohol use disorder (12–24 drinks per week)

Repairing Gut Microbiome and Reducing Inflammation

• Consuming 2–4 servings of low-​​sugar fermented foods per day 
  • Examples: kimchi, sauerkraut, natto, kefir, low-​​sugar yogurt
  • Reduces inflammatory markers and improves gut microbiome
• Probiotics and prebiotics may also be beneficial

• Focusing on gut microbiome may help those who have previously consumed alcohol heavily or are trying to reduce alcohol intake and improve health
  Weaning Off Alcohol and Managing Stress

• Weaning off alcohol can lead to increased cortisol levels, causing anxiety and stress

• It’s important to expect and manage this stress during the process
• The Master Stress episode of the Huberman Lab podcast offers various tools for managing stress

Hangovers and Anxiety

• Hangovers can cause anxiety due to increased cortisol levels from alcohol consumption
• The Master Stress episode can also help with managing anxiety caused by hangovers

Sleep Quality and Alcohol

• Alcohol disrupts sleep quality, affecting slow wave sleep, deep sleep, and REM sleep
• Even one drink can negatively impact sleep quality
• Poor sleep quality contributes to hangover symptoms

Gut Microbiome and Hangovers

• Alcohol destroys healthy gut microbiota, leading to leaky gut and other issues
• Supporting gut microbiome health with low sugar fermented foods, probiotics, or prebiotics may help alleviate hangover symptoms

Headaches and Hangovers

• Headaches during hangovers are caused by vasoconstriction, a rebound effect after alcohol-​​induced vasodilation
• Nonsteroidal anti-​​inflammatory drugs (NSAIDs) can alleviate headaches, but may have negative effects on liver and gut microbiome

Myths and Tips for Hangover Relief

• Eating food won’t cure a hangover, but it can slow alcohol absorption
• Drinking more alcohol (hair of the dog) is a bad idea, as it only delays and worsens the hangover
• Cold exposure, such as cold showers, may help with hangover relief by increasing epinephrine levels and potentially accelerating alcohol metabolism

• However, be cautious with cold exposure during a hangover, as alcohol lowers core body temperature and can be dangerous when combined with cold water immersion
  Dealing with Hangovers

• Hangovers are multifaceted, involving multiple organs, tissues, and systems

• Factors contributing to hangovers:
• Disturbed sleep
• Disrupted gut microbiome
• Dehydration and disrupted electrolytes
• Depletion of epinephrine and dopamine
• Strategies to alleviate hangovers:
• Replenish gut microbiome with low-​​sugar fermented foods
• Use safe, deliberate cold exposure to spike adrenaline and increase dopamine
• Consume electrolytes before and after drinking
• Be mindful of the type of alcohol consumed, as some types cause worse hangovers due to higher levels of conjuners (e.g., brandy)
• Maintain a healthy gut microbiome

Types of Alcohol and Hangover Severity

• Hangover severity is not directly related to sugar content in alcoholic drinks
• Hangover severity is associated with the presence of conjuners (e.g., nitrites) in alcohol
• Ranking of alcoholic drinks by hangover severity (from least to most severe):
• Ethanol diluted in orange juice
• Beer
• Vodka
• Gin
• White wine
• Whiskey
• Rum
• Red wine

• Brandy
  Alcohol Effects and Tolerance

• Hangover recovery involves a multifaceted approach

• Tolerance to alcohol is a complex phenomenon with roots in the brain 
  • Reduced effects of alcohol with repeated exposure
  • Caused by changes in neurotransmitter systems due to alcohol’s toxicity
• Dopamine and serotonin play a role in alcohol tolerance 
  • Initial alcohol consumption increases dopamine and serotonin, creating a sense of well-being
  • Subsequent alcohol consumption reduces dopamine and serotonin release
  • Tolerance leads to less “feel good” effects and more negative effects from alcohol
• Abstaining from alcohol can help reset the brain’s neurotransmitter systems 
  • The duration of abstinence needed depends on individual factors

Alcohol and Health

• Resveratrol in red wine is not a strong argument for health benefits 
  • The amount of red wine needed for resveratrol benefits would cause other negative effects
• Low to moderate red wine consumption (1–4 glasses per week) may have some positive effects 
  • Stress reduction and other micronutrients in red wine could contribute to health benefits

• Alcohol consumption, even light to moderate, can reduce cortical thickness in the brain

  • The reduction in cortical thickness scales with the amount of alcohol consumed
    Negative Effects of Alcohol Consumption

• Alcohol consumption can lead to shrinkage of gray matter volume and white matter tracts in the brain

• Increased risk of cancer, particularly breast cancer 
  • 4–13% increase in risk for every 10 grams of alcohol consumed
  • Alcohol alters DNA methylation and gene expression, leading to increased cancer risk
• Alcohol consumption during pregnancy can lead to fetal alcohol syndrome 
  • Diminished brain, limb, and organ development in the fetus

Comparing Alcohol to Cigarette Consumption

• Ingesting 10–15 grams of alcohol a day (one beer or glass of wine in the US) is sometimes compared to smoking 10 cigarettes a day 
  • This comparison is not exact and can vary depending on factors such as predisposition to lung cancer and duration of inhalation

Offsetting Negative Effects of Alcohol

• Consumption of folate and B vitamins (especially B12) may partially offset the increased cancer risk associated with alcohol consumption 
  • This is not a guarantee and does not completely eliminate the risk
• Pregnant individuals should not consume alcohol to avoid fetal alcohol syndrome

Alcohol and Hangover Supplements

• Some hangover supplements include folate and B12, which may help with recovery but are not well-​​supported by scientific literature

• Adequate consumption of folate and B12 may partially offset some increased cancer risk from alcohol consumption, but this is not a guarantee
  Alcohol and Pregnancy

• Alcohol is a toxin, and there is no safe type or amount for pregnant women

• Fetal alcohol syndrome exists due to alcohol’s ability to disrupt cellular processes
• Alcohol is a mutagen, which can mutate DNA and disrupt the precise development of an embryo
• Pregnant women should not consume any alcohol

Alcohol and Hormones

• Alcohol can increase the conversion of testosterone to estrogen
• In females, this may increase the risk of estrogen-​​related cancers (e.g., breast cancer)
• In males, this can lead to growth of breast tissue, diminished sex drive, and increased fat storage
• Regular ingestion of alcohol is likely to increase estrogen levels in both males and females

Alcohol Consumption

• No consumption of alcohol is better for health than low to moderate consumption
• Low to moderate consumption is better than high consumption
• Consider the negative effects of alcohol on the gut microbiome and stress system

• Acquire tools and proficiency with stress modulation that don’t involve alcohol consumption