Evaluation of alcohol metabolism in humans using the non-invasive [ ¹³C]-ethanol breath test - Influence of gender, Helicobacter pylori infection and polymorphism of alcohol-oxidizing enzymes

Background: The [¹³C]-ethanol breath test (EBT) has been proposed as a novel non-invasive laboratory test to detect the degradation of ethanol into CO₂. However, this method has not yet been evaluated clinically. Aim: To investigate the factors that influence [¹³C]-EBT. Methods: Twenty-six healthy volunteers were instructed to drink 100 mL of beer (4 g ethanol) containing 100 μL of [¹³C]-ethanol. Breath samples were collected every 15 min before and after the intake of ethanol solution and ¹³CO₂-enrichment was measured using mass spectrometry. CO₂ excretion was then calculated, and the results were evaluated using kinetic parameters (T_max, C_max, AUC). Results: T_max (min) was significantly shorter in men than in women but not C_max and AUC. Infection with H. pylori had no impact on all kinetic parameters. Genetic alcohol dehydrogenase (ADH) polymorphisms did not affect ¹³CO₂ excretion, but C_max (11.1 ± 3.4% dose/h, n = 16) and AUC (10.5 ± 3.4% dose) were slightly increased in aldehyde dehydrogenase (ALDH)-deficient individuals (heterozygote of ALDH2*2) (13.2 ± 3.2 and 12.9 ± 4.5, respectively; n = 10). Conclusions: [¹³C]-EBT is capable of assessing the metabolic processing of 100 mL beer in a non-invasive way. Kinetic parameters are partially influenced by ALDH polymorphism but not by gender, H. pylori infection or ADH polymorphism.