Concentration changes of methanol in blood samples during an experimentally induced alcohol hangover state

Inflammation, oxidative stress and gut microbiome perturbation: A narrative review of mechanisms and treatment of the alcohol hangover

Alcohol is the most widely abused substance in the world, the leading source of mortality in 15-49-year-olds, and a major risk factor for heart disease, liver disease, diabetes, and cancer. Despite this, alcohol is regularly misused in wider society. Consumers of excess alcohol often note a constellation of negative symptoms, known as the alcohol hangover. However, the alcohol hangover is not considered to have long-term clinical significance by clinicians or consumers. We undertook a critical review of the literature to demonstrate the pathophysiological mechanisms of the alcohol hangover. Hereafter, the alcohol hangover is re-defined as a manifestation of sickness behavior secondary to alcohol-induced inflammation, using the Bradford-Hill criteria to demonstrate causation above correlation. Alcohol causes inflammation through oxidative stress and endotoxemia. Alcohol metabolism is oxidative and increased intake causes relative tissue hypoxia and increased free radical generation. Tissue damage ensues through lipid peroxidation and the formation of DNA/protein adducts. Byproducts of alcohol metabolism such as acetaldehyde and congeners, sleep deprivation, and the activation of nonspecific inducible CYP2E1 in alcohol-exposed tissues exacerbate free radical generation. Tissue damage and cell death lead to inflammation, but in the intestine loss of epithelial cells leads to intestinal permeability, allowing the translocation of pathogenic bacteria to the systemic circulation (endotoxemia). This leads to a well-characterized cascade of systemic inflammation, additionally activating toll-like receptor 4 to induce sickness behavior. Considering the evidence, it is suggested that hangover frequency and severity may be predictors of the development of later alcohol-related diseases, meriting formal confirmation in prospective studies. In light of the mechanisms of alcohol-mediated inflammation, research into gut permeability and the gut microbiome may be an exciting future therapeutic avenue to prevent alcohol hangover and other alcohol-related diseases.

Alcohol-Induced Headache with Neuroinflammation: Recent Progress

Ethanol and other congeners in alcoholic beverages and foods are known triggers of alcohol-induced headaches (AIHs). Recent studies implicate AIHs as an important underlying factor for neuroinflammation. Studies show the relationship between alcoholic beverages, AIH agents, neuroinflammation, and the pathway they elicit. However, studies elucidating specific AIH agents’ pathways are scarce. Works reviewing their pathways can give invaluable insights into specific substances’ patterns and how they can be controlled. Hence, we reviewed the current understanding of how AIH agents in alcoholic beverages affect neuroinflammation and their specific roles. Ethanol upregulates transient receptor potential cation channel subfamily V member 1 (TRPV1) and Toll-like receptor 4 (TLR4) expression levels; both receptors trigger a neuroinflammation response that promotes AIH manifestation—the most common cause of AIHs. Other congeners such as histamine, 5-HT, and condensed tannins also upregulate TRPV1 and TLR4, neuroinflammatory conditions, and AIHs. Data elucidating AIH agents, associating pathways, and fermentation parameters can help reduce or eliminate AIH inducers and create healthier beverages.

Alcohol Hangover: Underlying Biochemical, Inflammatory and Neurochemical Mechanisms

AIM

To review current alcohol hangover research in animals and humans and evaluate key evidence for contributing biological factors.

METHOD

Narrative review with alcohol hangover defined as the state the day after a single episode of heavy drinking, when the alcohol concentration in the blood approaches zero.

RESULTS

Many of the human studies of hangover are not well controlled, with subjects consuming different concentrations of alcohol over variable time periods and evaluation not blinded. Also, studies have measured different symptoms and use varying methods of measurement. Animal studies show variations with respect to the route of administration (intragastric or intraperitoneal), the behavioural tests utilised and discrepancy in the timepoint used for hangover onset. Human studies have the advantage over animal models of being able to assess subjective hangover severity and its correlation with specific behaviours and/or biochemical markers. However, animal models provide valuable insight into the neural mechanisms of hangover. Despite such limitations, several hangover models have identified pathological changes which correlate with the hangover state. We review studies examining the contribution of alcohol's metabolites, neurotransmitter changes with particular reference to glutamate, neuroinflammation and ingested congeners to hangover severity.

CONCLUSION

Alcohol metabolites, neurotransmitter alterations, inflammatory factors and mitochondrial dysfunction are the most likely factors in hangover pathology. Future research should aim to investigate the relationship between these factors and their causal role.

Grape or grain but never the twain? A randomized controlled multiarm matched-triplet crossover trial of beer and wine

Background

Alcohol-induced hangover constitutes a significant, yet understudied, global hazard and a large socio-economic burden. Old folk wisdoms such as "Beer before wine and you'll feel fine; wine before beer and you'll feel queer" exist in many languages. However, whether these concepts in fact reduce hangover severity is unclear.

Objectives

The aim of this study was to investigate the influence of the combination and order of beer and wine consumption on hangover intensity.

Methods

In this multiarm, parallel randomized controlled matched-triplet crossover open-label interventional trial, participants were matched into triplets and randomly assigned according to age, gender, body composition, alcohol drinking habits, and hangover frequency. Study group 1 consumed beer up to a breath alcohol concentration (BrAC) ≥0.05% and then wine to BrAC ≥0.11% (vice versa for study group 2). Control group subjects consumed either only beer or only wine. On a second intervention day (crossover) ≥1 wk later, study-group subjects were switched to the opposite drinking order. Control-group subjects who drank only beer on the first intervention received only wine on the second study day (and vice versa). Primary endpoint was hangover severity assessed by Acute Hangover Scale rating on the day following each intervention. Secondary endpoints were factors associated with hangover intensity.

Results

Ninety participants aged 19-40 y (mean age 23.9), 50% female, were included (study group 1 n = 31, study group 2 n = 31, controls n = 28). Neither type nor order of consumed alcoholic beverages significantly affected hangover intensity (P > 0.05). Multivariate regression analyses revealed perceived drunkenness and vomiting as the strongest predictors for hangover intensity.

Conclusions

Our findings dispel the traditional myths "Grape or grain but never the twain" and "Beer before wine and you'll feel fine; wine before beer and you'll feel queer" regarding moderate-to-severe alcohol intoxication, whereas subjective signs of progressive intoxication were confirmed as accurate predictors of hangover severity. This trial was prospectively registered at the Witten/Herdecke University Ethics Committee as 140/2016 and retrospectively registered at the German Clinical Trials Register as DRKS00015285.

Urine methanol concentration and alcohol hangover severity

BACKGROUND

Congeners are substances, other than ethanol, that are produced during fermentation. Previous research found that the consumption of congener-rich drinks contributes to the severity of alcohol hangover. Methanol is such a congener that has been related to alcohol hangover. Therefore, the aim of this study was to examine the relationship between urine methanol concentration and alcohol hangover severity.

METHODS

N = 36 healthy social drinkers (22 females, 14 males), aged 18-30 years old, participated in a naturalistic study, comprising a hangover day and a control day (no alcohol consumed the previous day). N = 18 of them had regular hangovers (the hangover group), while the other N = 18 claimed to be hangover-immune (hangover-immune group). Overall hangover severity was assessed, and that of 23 individual hangover symptoms. Urine methanol concentrations on the hangover and control days were compared, and correlated to hangover (symptom) severity.

RESULTS

Urine methanol concentration was significantly higher on hangover days compared to control days (p = 0.0001). No significant differences in urine methanol concentration were found between the hangover group and hangover-immune group. However, urine methanol concentration did not significantly correlate with overall hangover severity (r = -0.011, p = 0.948), nor with any of the individual hangover symptoms. These findings were observed also when analyzing the data separately for the hangover-immune group. In the hangover group, a significant correlation with urine methanol concentration was found only with vomiting (r = 0.489, p = 0.037).

CONCLUSION

No significant correlation was observed between urine methanol concentration and hangover severity, nor with individual core hangover symptoms.

Natural Products for the Prevention and Treatment of Hangover and Alcohol Use Disorder

Alcoholic beverages such as beer, wine and spirits are widely consumed around the world. However, alcohol and its metabolite acetaldehyde are toxic and harmful to human beings. Chronic alcohol use disorder or occasional binge drinking can cause a wide range of health problems, such as hangover, liver damage and cancer. Some natural products such as traditional herbs, fruits, and vegetables might be potential dietary supplements or medicinal products for the prevention and treatment of the problems caused by excessive alcohol consumption. The aim of this review is to provide an overview of effective natural products for the prevention and treatment of hangover and alcohol use disorder, and special emphasis is paid to the possible functional component(s) and related mechanism(s) of action.

Alcohol hangover: a critical review of explanatory factors

OBJECTIVE

To describe the hangover phenomenon and briefly review its main explanatory factors.

DESIGN

Bibliographic research on main databases (Medline and Psychinfo).

RESULTS

Alcohol hangover is characterized by adverse physical and mental effects that occur the next morning after the intake of toxic doses of alcohol. This phenomenon is a very frequent experience among alcohol-consuming people and it has been associated to high socio-economic costs, mainly due to absenteeism and poor performance in academic and work settings. Multiple theories exist to explain the appearance and severity of hangover, such as direct or indirect effects of alcohol, alcohol withdrawal, and toxic effects of alcoholic beverage congeners or of alcohol metabolites. In addition, a number of intervening factors have been identified, such as vulnerability to alcohol dependence or psychological factors.

CONCLUSIONS

Although several studies analyze and describe hangover, it is still poorly understood. Further well-designed studies with a unitary methodology and clear operational criteria to define hangover are necessary in order to clarify such a phenomenon. We suggest some future working ideas that should be pursued in order to address the current shortcomings.