Ethanol, also known as ethyl alcohol or, colloquially, pure alcohol, is produced by the fermentation of fruits, grains, or tubers.
After consumption, 70 to 80% of the ethanol is absorbed in the duodenum and jejunum.
Food intake, by slowing gastric emptying, prolongs the time ethanol remains in the stomach, thereby altering its absorption kinetics. The time to reach peak plasma ethanol concentration is doubled if ethanol is ingested during a meal (90 minutes on average versus 45 minutes if the subject is fasting).
The volume of distribution for ethanol averages 0.50 L/kg in women and 0.65 L/kg in men. Ethanol easily crosses the placental barrier, and concentrations in amniotic fluid and in the fetus are close to the mother’s plasma concentrations.
After absorption, ethanol is distributed within a few minutes (distribution half-life: 7 to 8 minutes) to highly vascularized organs such as the brain, lungs, and liver.
Alcohol is eliminated primarily by the liver (95%). The remaining 5% is eliminated by the kidneys, skin, lungs, and saliva.
The pharmacokinetics of ethanol:

• differ between men and women, as women have a higher body fat mass, which results in a higher blood alcohol concentration for the same amount ingested.

• varies with age because the ratio of fat mass to lean mass changes over time in both men and women.

A standard drink contains approximately 10 grams of pure alcohol regardless of the type of alcoholic beverage (wine, beer, aperitif, or spirits).

These equivalents are based on the standard alcohol content of alcoholic beverages. Therefore, the volume of standard glasses varies depending on the alcohol content of the beverage.

Short-term effects that depend on blood alcohol concentration

Alcohol is a psychoactive substance. It alters consciousness and perception, and consequently affects how one feels and behaves. The immediate effects depend primarily on blood alcohol concentration.

An increased risk of traffic accidents

Even if the person doesn’t realize it, the effects of alcohol begin to appear after the very first drink. Alcohol slows reaction time. It impairs reflexes, alertness, and resistance to fatigue. It also disrupts vision, depth perception, and coordination. Furthermore, its disinhibiting effect leads people to underestimate danger and thus take risks: “forgetting” to fasten a seatbelt or wear a helmet, speeding, etc.
The risk of causing a fatal traffic accident increases eightfold when alcohol is consumed. This risk increases very rapidly with blood alcohol concentration: it is six times higher for a level between 0.5 and 0.8 g/L, and 40 times higher for a level above 2 g/L.
According to the latest road safety figures, alcohol is a factor in nearly one-third of fatal accidents.
The risks are heightened for drivers of vehicles (cars, trucks, scooters, etc.) as well as for pedestrians.

An increase in psychosocial risks

Acute alcohol intoxication exposes individuals to numerous social risks:

• self-harm

• aggression toward others, particularly domestic violence

• unprotected and/or unwanted sexual intercourse

Medium- and long-term consequences even with low consumption

Even without being a heavy drinker or alcohol-dependent, alcohol consumption influences the development of many diseases: cancers, cardiovascular and digestive diseases, nervous system disorders, and mental health issues... Alcohol can also cause more common problems (fatigue, high blood pressure, sleep disorders, memory or concentration problems, etc.).

Cancers

Alcohol is a proven carcinogen (Group 1), classified as such since 1988 by the International Agency for Research on Cancer (IARC).
The risk of developing certain cancers increases starting with just one drink per day, regardless of the type of alcohol consumed—whether wine, beer, or spirits. Thus, 19% of alcohol-related cancers develop in men who drink less than 40g of alcohol per day and women who consume less than 20g of alcohol per day.
In France in 2015, 8% of cancers were attributable to alcohol, representing approximately 28,000 cases. It is the second leading cause of preventable cancers after tobacco. This represents approximately 28,000 alcohol-related cancers in France, out of the 352,000 new cancer cases affecting adults over 30 years of age annually.
Seven types of cancer have a proven link to alcohol consumption: cancers of the mouth, larynx, pharynx, esophagus, liver, colon and rectum, and breast

Cardiovascular disorders

Regular alcohol consumption raises blood pressure and increases the risk of hypertension.
The effect of alcohol on blood pressure is dose-dependent, but the risk of hypertension increases differently in men and women:

• In men: any alcohol consumption is associated with an increased risk of hypertension.

• In women: the risk increases with consumption exceeding 30 g of alcohol per day.

It also increases the risk of strokes (hemorrhagic stroke) and atrial fibrillation (increased risk starting at 10 g of alcohol per day for men and 30 g of alcohol per day for women).

Cirrhosis

There is a dose-dependent relationship between alcohol consumption and cirrhosis. Causing progressive destruction of liver cells, which are replaced by fibrous tissue, the risk of cirrhosis increases significantly with consumption of:

• For women: 24 to 36g of alcohol per day

• For men, 36 to 48g of alcohol per day

Mortality from cirrhosis is significantly increased for any level of alcohol consumption in women and starting at a consumption of 12 to 24g of alcohol per day in men.

Effects on the Brain

In addition to impairments in attention, concentration, memory, abstract thinking, and executive functions, chronic alcohol intoxication can lead to Korsakoff’s syndrome, characterized by severe and irreversible memory impairment, a tendency to fabricate stories to compensate for memory loss, mood disorders, and more.

Addiction

Once dependence sets in, the harmful consequences are numerous and affect every aspect of the drinker’s life. Health deteriorates both physically and psychologically. Relationships with loved ones are disrupted, and professional life may also be affected.

Alcohol dependence is particularly toxic to the nervous system and causes numerous disorders:

• encephalopathies, resulting from vitamin deficiencies

• cognitive disorders, such as dementia

• epileptic seizures

• neuropathies 

Significant risks during pregnancy

Ethanol easily crosses the placental barrier, and concentrations in the amniotic fluid and in the fetus are close to the mother’s plasma concentrations.
In France, as in other Western countries, alcohol consumption during pregnancy is the leading cause of non-genetic mental disability in children.
Fetal Alcohol Spectrum Disorders (FASD) encompass a wide range of clinical manifestations, ranging from Fetal Alcohol Syndrome (FAS)—the specific form involving malformations—to isolated neurodevelopmental disorders, i.e., those without associated physical signs. In the absence of FAS, the term non-syndromic or non-specific FASD (FASD-NS) is used. These disorders are not limited to situations of heavy drinking or alcohol dependence.
The prevalence of FAS in the Western world is estimated at between 0.5 and 3 per thousand live births, while FASD is estimated at 9 per thousand live births.
Despite encouraging awareness, too many French people still downplay the impact of low or occasional alcohol consumption on the health of unborn children.