Alcohol and Health: dispelling the French paradox myth
On a global scale, one out of every three individuals consumes alcohol, which is responsible for over 2.8 million deaths each year. Alcohol consumption is associated with numerous health risks, leading to over 200 different illnesses and various problems. Some of these conditions are directly caused by alcohol, such as alcoholic cirrhosis and specific neurological disorders like Gayet-Wernicke encephalopathy and Korsakoff syndrome. Additionally, alcohol serves as a major risk factor for other diseases, notably cancers (mouth, pharynx, larynx, esophagus, liver, breast, colorectal cancer) and cardiovascular diseases (hypertension, ischemic heart disease). Individuals dependent on alcohol may also experience cognitive impairments, such as memory and coordination issues, which may gradually improve with abstinence.
The French paradox, referring to the consumption of small amounts of alcohol having a beneficial effect on health, does not exist. A study conducted by the French National Institute of Health and Medical Research (INSERM) in 2021 in France, a country known for high alcohol consumption, demonstrates that even low levels of alcohol consumption significantly contribute to new cases of cancer. The protective effects claimed by proponents of the French paradox reflect methodological issues in studies suggesting its existence. Decreasing the quantity of alcohol consumed, even if already low to moderate, could lead to a significant reduction in the number of deaths and the incidence of certain diseases.
What happens in my body when I drink alcohol?
When alcohol is consumed, it is absorbed into the stomach and small intestine and then enters the bloodstream. Once in the blood, alcohol is transported to various organs and tissues of the body, including the brain, where it exerts its effects.
The liver is primarily responsible for metabolizing alcohol. Alcohol is converted into a substance called acetaldehyde by an enzyme called alcohol dehydrogenase (ADH). Acetaldehyde is then converted into acetic acid by another enzyme called aldehyde dehydrogenase (ALDH), and then eliminated by the body.
The liver can metabolize approximately one standard unit of alcohol per hour. If more alcohol is consumed than the liver can process, the unmetabolized alcohol remains in the blood, leading to an increase in blood alcohol concentration and physiological and behavioral effects associated with intoxication.
When blood alcohol concentration decreases, it may be due to two main processes: alcohol metabolism by the liver and alcohol elimination by the kidneys (e.g., in urine) and lungs (via exhalation).
It is important to note that the rate of alcohol elimination can vary depending on factors such as body weight, gender, individual metabolism, presence of food in the stomach, and alcohol tolerance. There is no way to “sober up” faster than the natural process of alcohol metabolism and elimination, and the only safe solution is to allow time for the body to process the remaining alcohol in the system.
Alcohol and Cancer: The relationship between alcohol consumption and the risk of developing certain types of cancer is well established. Alcohol consumption is classified as carcinogenic by several health organizations, including the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO).
Types of Cancer: Alcohol consumption is associated with an increased risk of several types of cancer, including mouth, pharynx, larynx, esophagus, liver, breast, and colon cancer. The risk of cancer appears to increase with the quantity of alcohol consumed.
Mechanisms: The exact mechanisms by which alcohol promotes cancer development are not fully understood, but several factors may be involved. Alcohol can damage DNA, increase inflammation, and promote the production of certain hormones, all processes that can contribute to the formation of cancer cells.
Interaction with Other Risk Factors: Alcohol consumption can interact with other cancer risk factors, such as smoking. For example, smoking and drinking alcohol simultaneously can significantly increase the risk of developing mouth, throat, or esophageal cancer.
Levels of Consumption: Even moderate alcohol consumption can increase the risk of cancer. Studies have shown that the risk of certain cancers, such as breast cancer, increases even with moderate alcohol consumption.
Alcohol and the Brain: Alcohol consumption affects the brain in several ways, both in the short term and the long term.
Short-Term Effects: When you consume alcohol, it acts as a depressant of the central nervous system, meaning it slows down brain activity. This can lead to immediate effects such as impaired coordination, difficulty thinking clearly, reduced inhibition, and mood changes. These effects can vary depending on the amount of alcohol consumed and individual tolerance.
Impairment of Cognitive Function: Excessive and prolonged alcohol consumption can have a negative impact on cognitive function. This may manifest as short-term memory problems, difficulty concentrating, problem-solving issues, alterations in sensory perception, and impairment of executive (planning) and visuoconstructive (spatial orientation, object visualization, etc.) functions. In severe cases, chronic alcohol consumption can lead to permanent cognitive impairment. Cognitive impairment related to alcohol can be assessed using standardized scales such as the Montreal Cognitive Assessment (MoCA) and the BEARNI (Brief Evaluation of Alcohol-Related Neuropsychological Impairment).
Dementia: Recently, a link has been established between excessive alcohol consumption and the risk of dementia by a study conducted by INSERM in collaboration with Canadian researchers. Six or more drinks per day for men and four for women are associated with a tripling of the risk of dementia, including early-onset dementia occurring before the age of 65, such as Korsakoff syndrome directly attributable to alcohol, vascular dementia resulting from conditions like strokes, and neurodegenerative dementias like Alzheimer’s disease. Thus, the risk of developing Alzheimer’s disease is doubled in heavy alcohol consumers, making it a major modifiable risk factor.
Brain Atrophy: Excessive alcohol consumption can lead to brain atrophy, which means a reduction in the size and weight of the brain. This can affect different regions of the brain, including the prefrontal cortex, which is involved in decision-making and impulse control, as well as the hippocampus, which is important for memory.
Neurological Disorders: Alcoholism can also lead to the development of serious neurological disorders, such as Gayet-Wernicke encephalopathy and Korsakoff syndrome, which are caused by a deficiency in vitamin B1 due to poor nutrition associated with excessive alcohol consumption. These conditions can result in severe cognitive deficits and alterations in neurological function.
In summary, alcohol consumption can have a significant impact on the brain, affecting cognition, memory, and other neurological functions. Excessive and prolonged alcohol consumption can lead to permanent brain damage and serious neurological disorders, underscoring the importance of moderation in alcohol consumption to preserve brain health.
Some Protective Genetic Profiles Even Among Heavy Drinkers with High Consumption:
Like many diseases, we are not all equal in the face of alcohol consumption effects. Recent studies have indeed demonstrated a link between gut flora and vulnerability to alcohol. There would notably be a connection between the composition of the intestinal microbiota and the occurrence of complications in dependent individuals, especially liver diseases. Future genetic research aims to better understand individual vulnerability and obtain predictive data on the effectiveness of treatment.
Références
Contribution of alcohol use disorders to the burden of dementia in France 2008–13: a nationwide retrospective cohort study Michaël Schwarzinger, Bruce G Pollock, Omer S M Hasan, Carole Dufouil, Jürgen Rehm, for the QalyDays Study Group, Lancet Public Heath 2018, 3: e124–32
Common genetic variation in alcohol-related hepatocellular carcinoma: a case-control genome-wide association study Trépo, EricMeiller, Clément et al. The Lancet Oncology, Volume 23, Issue 1, 161 – 171