Mechanisms, myths and remedies
The mechanisms underlying hangovers are not fully understood. It is reasonable to assume that a wide range of cellular and physiological disturbances and damage play a role, including oxidative stress, inflammation, apoptosis and reduced sleep quality, with immunological, endocrine and haemodynamic involvement (12, 13). Depending on the degree of toxicity, this damage will be either reversible or irreversible. Given the broad nature of the mechanisms underlying hangovers, it is unlikely that any intervention will completely eliminate them. Once the damage has been done, there is little else to do but wait, although analgesics can be given for symptom relief. Drinking water can prevent dehydration resulting from alcohol-induced inhibition of vasopressin, but it does not reduce the hangover to any great extent. The intake of electrolytes, glucose, minerals or antioxidants has little or no clinical effect (14). Myths such as 'beer before wine and you'll feel fine; wine before beer and you'll feel queer' have been debunked in clinical trials (15). Thus, it is not the order of the different alcohol types that matters, but the total amount consumed and the rate of consumption that are the determining factors. Consuming different types of alcohol can potentially lead to larger quantities being drunk overall. It has been speculated that certain types of alcohol may cause worse hangovers due to the presence of other constituents (congeners), in the suggested order of pure spirit, beer, white wine, red wine, whisky and brandy. There is some evidence to support this (16), but again, it is the total alcohol exposure that is the determining factor.
A variety of remedies and measures have been proposed over the years to treat hangovers, but they lack documentation in the form of randomised controlled clinical trials, even after 8000 years of exposure. The trials that have been conducted often entail weaknesses and small sample populations. One of the main problems is that they cannot effectively blind participants to whether they are consuming alcohol or not, and are thus unable to eliminate the expectation of becoming hungover as a factor (17). Ernest Hemingway's cure for a hangover was tomato juice and beer. Consuming more alcohol to ward off a hangover can, at best, offer a temporary reprieve; at worst, it could exacerbate the situation. Some research also suggests that those who suffer worse hangovers than others are more likely to reach for the bottle the next day, thus facing a higher risk of developing alcoholism (18). However, the causal relationship between hangovers and alcoholism is probably more complex than that. To paraphrase the Norwegian playwright, Ludvig Holberg: 'Everybody says that Jeppe drinks, but nobody asks why Jeppe drinks'.
A pilot study found that isocapnic hyperpnea can accelerate ethanol elimination via the lungs, thereby achieving first-order kinetics alongside hepatic zero-order kinetics. Although this pilot study only had five participants, the mean half-life of elimination was dramatically reduced from 139 to 39 minutes without and with isocapnic hyperpnea (19). While there are no studies on the impact of this method on hangover symptoms, it is reasonable to assume that forced elimination and the resulting reduction in potential metabolites could have a positive effect. Respiratory alkalosis could limit usability for 'recreational purposes'.
Another pilot study shows that defecation can reduce intestinal alcohol absorption, thereby moderating hangover symptoms (20). In other words, alcohol should not be consumed on an empty stomach, but unnecessary blockages that could prolong alcohol absorption at the other end should also be avoided. NSAID medications and prostaglandin inhibition (21), or taking L-cysteine (22) (which binds to acetaldehyde), may have a role to play in symptom relief, but the evidence base is limited. Some data exist for clove extract, vitamin B6 and yeast-based supplements, but overall, the quality of the evidence base is generally low (23, 24).
If an effective hangover cure existed, people might drink even more