Urine methanol concentrations and alcohol hangover severity

Introduction: Congeners are substances, other than ethanol, that are produced during fermentation. These congeners include methanol and other alcohols, and alcohol metabolites such as acetaldehyde and aldehydes [1]. Both anecdotic evidence (i.e. high congener drinks such as tequila produce worse hangovers) and experimental studies confirmed than congener-rich beverages produce more severe hangovers [1,2,5]. It has been suggested that methanol, a major congener in alcoholic beverages, significantly contributed to the severity of alcohol hangover [2,3]. Concentrations of methanol differ greatly between alcoholic beverages, and were found to be highest in distilled spirits, such as brandies and whiskeys, and lowest in white wine and gin [2,3]. Alcoholic beverages containing more methanol are associated with a higher hangover severity scores [1,4]. The ability of ethanol to fully occupy the enzymes alcohol dehydrogenase and aldehyde dehydrogenase, blocking the metabolism of methanol, leads to accumulation of methanol causing hangover related symptoms [4]. Aim of the study: The aim of this study is to examine the relationship between methanol concentrations in urine samples and the severity of an alcohol hangover. Methods: N= 36 healthy social drinkers (22 females, 14 males), aged 18 to 30 years old, participated in a naturalistic study, comprising a hangover day and a control day (no alcohol consumed the previous three days). The amount, type of drinks, day, and place of alcohol consumption were the subjects own choice. Urine samples were collected in the morning, on both the control and the hangover day. Collected samples were analyzed for methanol contents using gas chromatography. Methanol concentrations in samples collected on hangover day were compared to samples collected on control day, distinguishing between males and females, by performing a paired t-test. The Hangover Severity Scale (HSS) was completed on both test days. Methanol concentrations were correlated to hangover severity and amount of consumed alcoholic drinks. All statistical analyses were performed using SPSS. Results: On average, participants consumed 11.6 (6.1) alcoholic drinks in the alcohol condition. Methanol levels were significantly higher on hangover day compared to control day (p = 0.00). On hangover day, methanol levels were positively correlated with the amount of alcoholic drinks (p = 0.38). However, methanol levels on hangover day were not significantly correlated with hangover scores (p = 0.157). No significant differences were observed between males and females. Conclusion: Although urine methanol levels are significantly higher on a hangover day, no significant correlation was observed between urine methanol concentration and hangover severity scores. In addition, urine methanol concentration is significantly higher when more alcoholic beverages were consumed. Taken together, this data suggests that methanol does not significantly contribute to the severity of alcohol hangover. Further research is needed to disentangle the exact role of methanol in the pathogenesis of the alcohol hangover.