How Alcohol Is Absorbed & Metabolized In The Body
Alcohol’s main ingredient, ethanol, travels through the stomach and small intestine before it starts to be absorbed. Once absorbed, alcohol travels to the liver to be broken down or metabolized.
The liver plays the largest role in metabolizing alcohol. It contains enzymes that break alcohol down into smaller parts, or metabolites.
Drinking too much alcohol can put you at a higher risk for liver damage. Other parts of the body that are exposed to alcohol, such as the blood vessels, pancreas, and heart, can also be at risk due to long-term alcohol use.
The Absorption Of Alcohol In The Body
Alcohol’s main ingredient is almost always ethanol, which is broken down by the human body in a specific way. Other additives and ingredients are broken down differently.
When you drink alcohol, some of it is immediately absorbed by body tissue in your mouth and esophagus. Most alcohol goes to your stomach, where it travels to the small intestine and travels to your liver. Over 90% of all alcohol ingested is broken down in the liver.
Other parts of your body, like your pancreas, brain, and gastrointestinal tract play small roles in alcohol metabolism. These parts of the body may be at higher risk for the harmful effects of alcohol. About 5% of alcohol leaves the body unchanged through excretion (urine).
Your Liver & Alcohol Intake
Once ethanol reaches your liver, it starts to be broken down by the enzyme alcohol dehydrogenase (ADH).
ADH breaks down alcohol into acetaldehyde, a toxic substance. Acetaldehyde is then broken down by aldehyde dehydrogenase (ALDH) into acetate, a less toxic substance.
Acetate can be broken down further into carbon dioxide and water. Ethanol, acetate, and acetaldehyde all travel through your bloodstream to the kidneys, where they are excreted through urine. An average human liver can break down about one standard drink per hour.
If you drink alcohol faster than the liver can break it down, its metabolites go through your bloodstream again before going back to the liver. This can lead to an increase in your blood alcohol concentration, also known as blood alcohol level or BAC.
Factors That Affect Alcohol Absorption
There are many genetic and non-genetic factors that affect alcohol absorption.
Genetics can affect how your body breaks down alcohol. Factors such as liver size, body composition, and body weight can be influenced by genetics. Genetics can also affect the type and amount of ADH and ALDH enzymes in your body.
Certain types of ADH and ALDH enzymes can lead to faster acetaldehyde buildup in the body. Since acetaldehyde is toxic to the body, large amounts can make drinking feel unpleasant. People with these genes may be at a lower risk of chronic alcohol abuse.
Alcohol Content & Rate Of Consumption
A higher concentration of alcohol in your alcoholic beverage is an important, non-genetic factor in alcohol absorption. If alcohol consumption happens on an empty stomach, the rate of absorption is also much higher.
Fizzy alcoholic drinks, or ones that are aerated with carbon dioxide, can speed up absorption. These include drinks like champagne or drinks that are mixed with soda. Drinking alcohol on a full stomach, meanwhile, can lead to lower absorption.
Faster, higher absorption means more alcohol will get into your blood, leading to higher BAC levels. Knowing your body’s limits can help you understand how much you should drink in one setting, especially if you’re trying to stay under the legal limit.
The Harmful Effects Of Alcohol
Your liver is exposed to a high amount of alcohol when you drink, especially compared to the rest of your body. Many long-term effects of alcohol abuse involve the liver, including forms of liver disease, liver cancer, and even liver failure.
Acetaldehyde, a main metabolite of alcohol, can cause harmful effects in other parts of your body. It is linked to shrinking blood vessels, high blood pressure, irritation in the stomach lining, and several types of cancer.
Alcohol can be harmful to your physical and mental health in the long term. If you are looking for professional help to quit drinking, contact our helpline today.
National Library of Medicine: PubMed Central - ABC of alcohol: Alcohol in the body
National Institute on Alcohol Abuse and Alcoholism (NIAAA) - Alcohol Metabolism
PLOS Medicine - Alcohol Intake and Blood Pressure: A Systematic Review Implementing a Mendelian Randomization Approach
The Alcohol Pharmacology Education Partnership - How is Alcohol Eliminated from the Body?
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