Evidence check: ADH1B in the context of Darmgesundheit

The link between ADH1B variants and gut health is scientifically weak. ADH1B encodes alcohol dehydrogenase, which oxidizes ethanol to acetaldehyde. Certain variants (e.g., rs1229984, Arg48His) accelerate this step, leading to higher acetaldehyde levels. Acetaldehyde is a reactive toxin that can damage the intestinal barrier and promote inflammation in vitro. Additionally, alcohol consumption alters the microbiome—chronic intake reduces beneficial bacteria and increases permeability („leaky gut“). However, most data come from cell or animal models; direct human studies linking ADH1B genotypes to gut health parameters (e.g., zonulin, endotoxemia, microbiome diversity) are largely absent. A DNA test marketing ADH1B as a „gut health gene“ overstates the evidence. The actual relevance depends heavily on alcohol intake: in abstainers, ADH1B has little impact on the gut. In regular drinkers, the genotype might modulate susceptibility to alcohol-induced gut damage, but this is not sufficiently supported by clinical studies. Conclusion: Mechanistically plausible, but not actionable for practice without validated biomarkers or dietary recommendations.