As one of humanity's oldest neuroactive substances, alcohol's health effects have always been a double-edged sword. The latest systematic review published by the US Department of Health and Human Services (HHS) in 2025 shows: For every 1,000 adults who drink more than 7 times per week, 1 person dies from alcohol-related diseases. This dose-dependent toxic characteristic is overturning the traditional notion that 'moderate drinking is beneficial to health.'

I. Ethanol Metabolism Mechanism and Cellular Toxicity
When alcohol (ethanol) enters the body, its metabolic process itself is the source of toxicity:
- First-pass metabolism: Gastric mucosal ADH enzymes break down 20% of ethanol, producing free radicals.
- Liver oxidation: The CYP2E1 enzyme system converts ethanol to acetaldehyde (an IARC Group 1 carcinogen).
- Mitochondrial damage: Acetaldehyde reduces mitochondrial complex IV activity by 60% [10].
This metabolic chain causes each alcohol molecule to produce 4.6×10^19 free radicals, directly attacking DNA and inducing mutations [11].
II. Organ-Specific Damage
1. Liver: Collapse of the 'Silent Chemical Factory'
- Dose effect: Daily intake of 80g ethanol (≈5 cans of beer) increases the risk of cirrhosis to OR=27.3.
- Triple hit: In the pathological process of fatty change→fibrosis→liver cancer, alcohol increases hepatic stellate cell activation rate by 300%.
- Latest finding: Even after quitting alcohol, the risk of cancer due to epigenetic modifications persists for over 10 years [12].
2. Brain: Destruction of Neural Plasticity
- Structural changes: Chronic drinkers experience a 15% reduction in hippocampal volume and a 0.3mm/year decrease in prefrontal cortex thickness.
- Cognitive impairment: Working memory error rate has a linear correlation with alcohol consumption (R²=0.89).
- Withdrawal crisis: GABA receptor downregulation leads to a 40% reduction in seizure threshold [10].
3. Cancer: No Safe Threshold for Dosage
The latest WHO statement emphasizes: Every 10g of alcohol/day (≈1 glass of wine) leads to:
- Oral cancer risk ↑29%.
- Breast cancer risk ↑12%.
- Colorectal cancer risk ↑8% [11].
The mechanisms involve acetaldehyde-DNA adduct formation, folate metabolism disorders, elevated estrogen levels, and multiple pathways [1].

III. Cardiovascular Controversies: The Illusion of Protection
The 'J-curve' shown in early observational studies is facing methodological challenges:
- 'Abstainer bias': Control groups include people who quit drinking due to illness, distorting statistical results.
- Dose reassessment: The 2025 CALIBER study confirms that more than 100g of alcohol per week significantly increases:
- Atrial fibrillation risk ↑16%.
- Hypertension risk ↑13%.
- Myocardial fibrosis degree ↑22% [9].
- Alternative mechanism: Resveratrol in red wine is difficult to reach effective concentrations in the human body, requiring daily consumption of 300L of red wine to produce antioxidant effects [5].
IV. Multiplied Risks for Special Populations
- Women: With the same amount of alcohol consumption, blood alcohol concentration (BAC) is 20% higher than men, with a sharp increase in breast cancer risk.
- Adolescents: Continuous drinking before age 25 delays prefrontal development by 2-3 years.
- Asian populations: 50% carry the ALDH2*2 mutation, increasing the risk of acetaldehyde accumulation by 6 times [4].
V. Metabolic Kinetics Warning
- Absorption rate: Drinking on an empty stomach advances the BAC peak by 40 minutes.
- Individual differences: A 70kg male metabolizes only 8-10g of ethanol per hour (≈1 can of beer).
The 2025 Global Burden of Disease study shows: Alcohol use ranks 7th among risk factors for premature death, directly causing 3 million deaths annually. Facing increasingly clear scientific evidence, the World Health Organization (WHO) provides clear advice: 'No amount of alcohol consumption can be considered safe, and the healthiest choice is to not drink at all.' [11] For those who have already formed drinking habits, they can refer to the reduction plan from the US National Institutes of Health (NIH): reduce drinking amount by 20% each week, combined with vitamin B1 supplementation, to achieve safe withdrawal within 12 weeks.