Alcohol in the body is absorbed primarily in the small intestine after drinking. But our mouth, throat and stomach also absorb small amounts. Alcohol doesn’t need to be digested to be absorbed.
I. Absorption of Alcohol in the Body.
II. How Alcohol in the Body is Eliminated.
III. Alcohol and (Non-)Weight Gain.
IV. Practical Personal Implications.
I. Absorption of Alcohol in the Body
We think of the stomach as digesting food completely. It’s true that it largely physically and chemically breaks down food. But it only absorbs about 10% of the nutrients we derive. In fact, the small intestine does most of the work.
The stomach releases the partially digested food. It’s into the small intestine when it is broken down more.
The small intestine is about one inch in diameter and ten feet long. Yet it absorbs about 90% of the nutrients we get.
It’s able to do this for a simple reason. The interior walls of the organ have large wrinkles. These wrinkles are covered with tiny finger-like projections (villi). In turn, they’re covered with even smaller microvilli. There are perhaps 130 billion microvilli per square inch. The effect of the wrinkles, villi, and microvilli is to greatly increase the surface area exposed to partially digested food (chyme).
The small intestine absorbs about 80% of the alcohol we consume. The organ has three major regions.
- The duodenum is the first section. It’s about ten inches long. It mixes chyme with liver bile and pancreatic juice. This completes the digestive process.
- The jejunum is the middle section of the small intestine. It’s about three feet long. This is where most nutrients are absorbed. Also, it’s where most alcohol is absorbed.
- The ileum is the last section of the small intestine. It’s about six feet long and empties into the large intestine. The ileum completes the absorption of nutrients not yet absorbed. It also absorbs alcohol.
The large intestine continues the process of absorbing
nutrients. It’s largely there that the body produces its own alcohol. Yeast converts sugar into alcohol and gas.
The large intestine (including the rectum) also absorbs alcohol. Usually, there is little alcohol remaining in the large intestine. Yet it rapidly absorbs alcohol directly into the bloodstream.
For this reason, some people take beer enemas. Some use wine, which has more concentrated alcohol (but not more alcohol). But wine enemas have sometimes caused death.
Skin and Lungs
Skin can also absorb alcohol. For example, people who use hand sanitizers containing alcohol absorb some of the alcohol through their skin. As a result, they can have false positive EtG alcohol urine test results. The EtG urine alcohol test is widely used to test compliance of people who are mandated not to drink alcohol. Discover more at EtG Urine Alcohol Test Unreliable.
Another way people can get alcohol in the body is by breathing alcohol vapors. An Alcohol Without Liquid (AWOL) device is available where legal. The machine vaporizes alcohol which customers inhale.
The AWOL is deceptively marketed as a way to avoid carbohydrates in alcohol. But liquor (distilled spirit) contains no carbs. Whiskey, Scotch, vodka, rum, gin, tequila and other spirits are carb-free. There’s absolutely no need to inhale them to avoid carbs. Nor to avoid sodium, fat, or gluten. That’s because they contain none.
On the other hand, customers lose the tastes and mouth sensations from savoring a drink. It’s like taking a fistful of vitamin tablets instead of enjoying a delicious meal. Learn more at AWOL: Alcohol Without Liquid.
Once the alcohol enters the bloodstream, it quickly travels to all areas of the body. And it’s more soluble in water than fat. Therefore, people with a high proportion of body fat will have higher blood alcohol concentration (BAC) than thin people. This is true even if they drink the same amount of alcohol in the same amount of time.
This is one reason women tend to have a higher BAC when they weigh the same. Also, women tend to weigh less than men. This further increases BAC.
But there’s yet another reason for this inequity between men and women. Women have less dehydrogenase (see below) to break down some alcohol before it enters the bloodstream. In addition, hormonal changes during the menstrual cycle can also reduce metabolism. This further increases the impact of alcohol. Learn more at Alcohol is sexist. It’s unfair and unjust. But it’s important to know.
II. How Alcohol in the Body is Eliminated
The liver breaks down over 90% of the alcohol in the bloodstream. Breath expels up to about 5%. Urine also carries away up to about 5%. But sweat and feces eliminate only negligent amounts.
The body eliminates alcohol from the body at a fairly constant. It’s about .015 of BAC per hour.
For example, a person with a BAC of .15 will have no measurable alcohol in the blood after ten hours. That’s because .15 divided by .015 equals 10. Here are some other examples.
|BAC Level||Metabolism Time in Hours|
It’s important to know that BAC can continue to rise for a period of time after the last drink. That’s because absorption contines after that drink.
Metabolism occurs in three steps.
- The enzyme alcohol dehydrogenase (ADH) converts alcohol into acetaldehyde.
- Then another enzyme, aldehyde dehydrogenase (ALDH), converts the acetaldehyde into acetate.
- Finally, the acetate mainly brakes down into carbon dioxide and water. These leave the body. But if the body doesn’t need any of the remaining acetate for energy, it converts it into fatty acids.
III. Alcohol and (Non-)Weight Gain
Alcohol contains calories. Yet drinking in moderation doesn’t lead to weight gain. Indeed, some studies find a small weight loss among women who drink.
The medical evidence of this is strong. A large number of studies of thousands of people report it. Many are very large.
It’s not clear why moderate alcohol drinking doesn’t increase weight. Some researchers report that the body may not use alcohol efficiently. Alcohol also appears to increase metabolic rate greatly. Then the body burns more calories. Other research finds that sugar consumption drops as alcohol drinking goes up. Learn more at Alcohol, Calories and Weight: Surprising Facts.
IV. Practical Personal Implications
- Remember that standard drinks of beer, dinner wine, and spirits or liquor have the same amount of pure alcohol. It’s six-tenths of one ounce.
- Stick with standard drink sizes. That makes it easier to keep track of your intake of pure alcohol.
- Food in the stomach reduces the absorption of alcohol.
- Nibbling food while drinking slows absorption of alcohol.
- Pace your drinks. A common rule of thumb is no more than one alcoholic drink per hour.
- Remember that Alcohol is Sexist.
- Alternate non-alcoholic with alcoholic drinks.
- Sip your drinks slowly.
- Don’t play drinking games.
- Effervescent drinks cause more rapid alcohol absorption.
- Also diet drinks cause more rapid absorption.
- Follow medical advice about drinking with any meds.
V. Resources on Alcohol in the Body
For more detail about this subject, visit
- How Alcohol Is Metabolized in the Human Body.
- How Is Alcohol Metabolized by the Body?
- This site gives no advice. Please see your doctor for answers.