Involvement of acetaldehyde for full protection against alcoholism by homozygosity of the variant allele of mitochondrial aldehyde dehydrogenase gene in Asians.
Level 3 - non-randomized controlled study
Non-randomized controlled physiological challenge study with matched genotype groups
What was done
Researchers recruited 18 adult Han Chinese men (selected from a screened cohort of 273 men and matched by age, BMI, nutritional status, and ADH genotype) divided into three groups of six by ALDH2 genotype: ALDH2*1/*1, ALDH2*1/*2, and ALDH2*2/*2. After administering a low oral dose of ethanol (0.2 g/kg body weight), investigators measured blood ethanol and acetaldehyde concentrations, cardiac and extracranial/intracranial arterial hemodynamics, and self-rated subjective sensations for 130 minutes.
What was found
The abstract reports no exact numerical values. It reports that ALDH2*2/*2 homozygotes experienced a large and prolonged accumulation of acetaldehyde in the blood, pronounced cardiovascular hemodynamic responses, and self-reported general discomfort lasting up to 2 hours following alcohol ingestion.
Why it matters
This study provides the physiological mechanism—intense physical discomfort and hemodynamic reactivity due to rapid acetaldehyde accumulation—explaining the genetic protection against alcoholism in individuals homozygous for ALDH2*2.
Limits
The sample size is very small (n=6 per group), includes only adult Han Chinese men, and the abstract omits quantitative point estimates, confidence intervals, and exact p-values.
Cited by
- supports Many Han Chinese individuals lack or have low levels of the enzyme that breaks down acetaldehyde into acetic acid during alcohol metabolism, making alcohol consumption less pleasant and specifically lowering their risk for alcoholism.