Alcohol is absorbed differently.

Why does alcohol get into the bloodstream so quickly?

Alcohol is absorbed very quickly by the blood and spreads easily to all the organs. That’s because alcohol molecules are very tiny. They don’t have to be broken down by digestive enzymes to get into the blood, and they dissolve easily in water and fat, both of which are prime components of the human body.

Why is alcohol absorbed more quickly when the stomach is empty?

Alcohol moves quickly from the mouth to the stomach and on to the intestines. Some of it is absorbed directly through the mucosal lining of the mouth and oesophagus; some is absorbed through the walls of the stomach and the rest is absorbed by the intestines, mainly the small intestine.

If there is no solid food in the stomach or intestines, the alcohol will come into contact with the intestinal walls more easily and pass quickly into the blood. All the alcohol of one drink may well be absorbed within 30 minutes.

However, if your stomach is relatively full, the alcohol will stay there longer. The absorption process will be slower and may take up to 90 minutes.

Why is stronger alcohol absorbed more slowly?

Beverages that are more than 20% alcohol irritate the lining of the stomach. This slows the opening of the pyloric valve, through which the contents of the stomach pass into the small intestine. Drinking several shots of spirits one after the other in the hope of getting drunk quickly may actually produce a delayed reaction.

Why does alcohol go to your head so quickly?

Once it’s in the bloodstream, the alcohol spreads to all parts of the body and is distributed in all tissues containing water. Because alcohol is carried by the blood, it follows that it will be delivered particularly quickly to organs with many blood vessels, such as the brain, the lungs and the liver.

Alcohol is eliminated differently

Why is there alcohol in the breath you exhale and in breast milk?

Some alcohol (about 10%) is eliminated as is, through urine or perspiration. It can also be eliminated through the breath, since the bloodstream carries it to the lungs. This is why a breathalyzer can effectively measure your blood alcohol level (breath alcohol testing device).

Nursing mothers should be aware that the concentration of alcohol in breast milk is about 10% higher than in the blood, because of the high water content of the milk.

How is alcohol metabolized by the liver?

Most of the alcohol (about 90%) is eliminated by the body’s metabolism. While the kidneys and gastro-intestinal tract play a role in this process, the liver is the organ primarily responsible for transforming the alcohol absorbed by the blood. In the first stage of metabolism in the liver, an enzyme called alcohol dehydrogenase transforms the alcohol into acetaldehyde, a highly toxic substance that affects the entire body. This activates another enzyme – acetaldehyde dehydrogenase – which transforms the toxic acetaldehyde into inert, harmless molecules of acetate, or acetic acid.

Why do different people eliminate alcohol differently?

No matter how much or how little you drink, your liver can only metabolize 15 17 mg of alcohol every hour. The speed at which it does so depends primarily on the number of metabolic enzymes in the liver, which varies from one individual to the next and is thought to be genetically determined. Other factors also influence the process.

Consequences and immediate effects of alcohol absorption.

Why does alcohol have such an impact on the brain?

Before it reaches the liver, the alcohol in the blood affects other vital organs that contain a lot of water and require a significant volume of blood in order to function. The most immediately observable effects can be seen in the brain.

Alcohol restricts a number of brain functions by stimulating the brain’s pleasure centres. At first, the effects are pleasurable: there is a reduction in stress and inhibitions, and a sensation of either calm or excitement.

How you feel depends on your mood at the time. If you are sad or angry before you drink, the alcohol may initially put you in a better mood. But then the opposite occurs, and you may well end up even sadder or angrier than you were before you started drinking.

Why does alcohol change behaviour?

Numbing effects

As your blood-alcohol level rises, your brain’s motor and sensory centres are affected. You begin to have difficulty with coordination and fine motor functions, and your reaction time slows.

The effects can be minor or major, depending on how much you drink. If you have a blood-alcohol level of .08, or 80 mg of alcohol per 100 ml of blood – the legal limit for driving a motor vehicle in Canada – your reaction time will be 30% 50% slower than when you have no alcohol in your blood. For example, driving under the influence of alcohol will make it difficult to brake quickly if the car ahead stops suddenly.


As you become intoxicated, your speech, thought processes and senses are affected. Your cognitive and verbal skills are diminished; and since these are the skills that allow you to resolve conflicts, there is a greater likelihood of aggressive and violent behaviour.


The part of the brain that controls vomiting is affected by the alcohol and toxic acetaldehyde circulating in your blood.


Alcohol also affects the pituitary gland, resulting in reduced secretions of the anti-diuretic hormone that maintains the body’s proper hydration level. More specifically, the kidneys are no longer able to reabsorb sufficient water from your urine, and your body ends up eliminating more water than it absorbs. The symptoms of dehydration are fatigue, back and neck pain, and headaches.


The immediate effects on the brain are often less apparent among people who drink regularly, because they have developed a strong tolerance for alcohol. As a result, they can often drink a great deal without feeling too many short-term effects. Such tolerance is both metabolic – the liver processes the alcohol more quickly and efficiently – and functional – the person learns to compensate for the deficits caused by alcohol.

Nevertheless, the harmful effects of drinking will be seen and felt in the long term. In fact, people whose bodies are habituated to the immediate effects of alcohol are generally those who drink abusively.

How does alcohol affect other vital organs?

Heart and cardiovascular system

Just one or two drinks can affect your heart rate, blood pressure, circulation and contractions of the heart muscle, including its ability to pump blood through your body. While these reactions are generally not considered significant from a clinical point of view, they can be more serious if you already suffer from cardiovascular problems.

Among other things, alcohol causes the small blood vessels beneath the skin to dilate, which increases blood circulation. You may have noticed that some heavy drinkers have a particularly ruddy complexion. What you’re seeing is the result of the dilated blood vessels.

The dilation of blood vessels also causes heat loss, and a drop in body temperature. Contrary to popular belief, it is very dangerous to drink alcohol to “warm up” when you are exposed to the cold.


As soon as even a small amount of alcohol is ingested, the intestines begin to secrete acid. As the blood-alcohol level rises, secretions of pepsin, a digestive hormone, are reduced, leading to an irritation of the intestinal walls and eventually diarrhea.


The pancreas produces insulin, which the body needs to control blood sugar levels. Drinking causes a sudden spike in blood sugar; the pancreas responds by producing more insulin. This causes a rapid drop in blood sugar and the symptoms of hypoglycaemia – dizziness, headaches, difficulty concentrating, depression, anxiety, trembling, cold sweats, heart palpitations, loss of coordination, and stomach aches.

Alcohol and the human body