Hangovers: Prevention Rather Than Cure?

Hangovers: Prevention Rather Than Cure?

It’s something that every time period has a remedy for: medieval doctors recommended raw eel with a side of almonds, while the Victorians drank warm water mixed with ash. Nowadays, the quest for ‘hangover cure’ has an unsurprising peak in google searches around the end of December each year:

Unfortunately, this search is likely to be unsuccessful. Clinical trials performed on hangover remedies are scarce, but a recent review on those available concluded that no substance was useful in curing alcohol hangover and that abstinence was the best strategy.

Not the most welcome advice before a Christmas party.

Can we approach this in a scientific way? If we understand why a hangover occurs, can we take measures to prevent one, rather than curing the damage when it's already done?

Despite its long history, the hangover state is poorly understood. Veisalgia is the technical term but this covers a range of vague sounding symptoms such as ‘headache’, ‘anxiety’ and ‘poor sense of well-being’. Criteria that are difficult to define and difficult to measure. This area of science is hampered by a lack of knowledge. Acute alcohol intoxication is well studied - since 1965 almost 5000 articles have characterised its effects. But only 100 studies in the same time period deal with the alcohol hangover. This means that the biological changes that occur following a night of drinking remain less well defined.

Ethanol – the main alcohol present in an alcoholic beverage- is extremely harmful and can seriously disrupt the function of the brain, heart and other organs. Ethanol is mainly dealt with by the liver: it's broken down in several steps before it can be removed from the body, producing toxic by-products along the way that can also cause damage. Although the actions of alcohol upon its consumption are well characterized, the exact mechanisms for its aftermath are less obvious.

Many people point to dehydration as a major factor. Once you start drinking, alcohol inhibits the release of vasopressin, a hormone that regulates how much water is lost from the body as urine. The body will start to expel more liquid than is taken in, resulting in dehydration, despite the large quantities of liquid that can be consumed.

However, as this is an uncertain field, there are other theories. One group of scientists- The Alcohol Hangover Research Group (AHRG)-  aims to contradict common myths about alcohol and the hangover response. Formed in 2009 by Joris Verster from Utrecht University, their goal is to ‘elucidate the pathology, treatment and prevention of the alcohol hangover’. Interestingly, they suggest that dehydration is not a major cause of a hangover- they are merely two events that unfortunately coincide. Instead, they point to a different culprit behind the hangover response: the immune system. The workings of the immune system are closely intertwined with the functioning of the brain and they suggest that the mental symptoms such as impaired concentration, reduced coordination and dizziness are a result of a disrupted immune response.

Immune cells communicate with each other through small molecules called ‘cytokines’. The hangover state has been associated with increased levels of cytokines known to cause inflammation and adverse effects such as nausea, headaches and vomiting. In animals, injection of these molecules can cause symptoms such as weakness, impaired concentration and reduced activity- all symptoms associated with the mental effects of a hangover. This is an interesting concept, but it needs to be further strengthened. Studies where injecting healthy patients with the correct cytokine cocktail to induce hangover symptoms would be extremely convincing - but perhaps not the most ethical experiment to set up.   

 So, with some understanding of the biological effects of alcohol and mechanisms of a hangover, are there some obvious tactics to prevent the onset of symptoms?

The simple answer is no. The only 100% certain method of avoiding a hangover is to avoid alcohol. But if total abstinence is not a possibility, then alcohol limitation is the next best strategy. By AHRG estimates, the hangover threshold is drinking enough to cause a peak blood alcohol concentration of approximately 0.1%. But peak blood alcohol concentration is not only determined by amount of alcohol consumed- body weight, sex, time spent drinking, and strength of the alcohol also contribute. This makes it difficult to calculate, especially in the midst of a busy night out.  

Preparation before drinking also goes a long way, so have a good meal before the night begins. Once consumed, alcohol is mainly absorbed into the bloodstream from two points: first the stomach (poorly absorbent) and then the small intestine (highly absorbent). The stomach is a critical point in controlling blood alcohol concentration as it manages how fast alcohol can pass into the much more absorbent small intestine. A full stomach has a slower rate of emptying into the small intestine, reducing the rate of alcohol absorption. This allows extra time for your body to metabolise the alcohol already in the bloodstream and means less chance of your blood alcohol concentration rising over the threshold of 0.1%. This is a simple approach to reduce intoxication and maximise the chances of avoiding a hangover. Eating after drinking to ‘soak up the booze’ however is not so effective.

Strategically choosing your drinks can also lessen the morning after effects as not all drinks are created equal. Ethanol is the type of alcohol we want in our alcoholic beverages. But a side effect of their manufacture is the presence of many different by-products that are not so desirable. The congener alcohols, such methanol, are one group of these. Each type of alcoholic beverage will have characteristic amounts of these contaminants: dark liquors such as whiskey and cognac typically have higher congener amounts compared to clear liquors such as vodka and gin. For methanol, vodka has only 1% of the methanol content of a similar amount of whiskey. In a direct comparison of people drinking vodka versus bourbon, the bourbon drinkers scored higher on the hangover severity scale the morning after drinking.

But what if you don’t want the trouble of monitoring when you eat and restricting what you drink? Is there an easier ‘over the counter’ remedy to prevent alcohol catching up the next day?

Although nothing has been successful as a hangover cure, certain substances were effective in reducing hangover symptoms in a very small number of trials. Importantly, the substance was taken before the alcohol. These substances are a diverse group, including extract from the prickly pear cactus plant, a variant of vitamin B6 (pyritinol) and a migraine remedy (tolfenamic acid). One thing they do have in common is their apparent ability to reduce the body’s inflammatory response-  supporting the AHRG’s suggestion that inflammation and the immune system are key drivers of the alcohol hangover. However, the studies on all of these substances are small and the most they could boast was a mild reduction in symptoms. Hangover immunity from a bottle is definitely not in sight just yet.

One final futuristic possibility: what about a type of substance that could provide the highs of alcohol without the lows? British scientists are identifying compounds that affect the brain in the same way as alcohol, but without the toxic by-products and harmful effects. They are currently bidding for the funding necessary to bring their products to the market, with hopes of their ‘Alcosynth’ compounds able to ‘completely replace alcohol by 2050’

Until then, the best advice is to eat well, drink small amounts and choose drinks with lower contaminants. And have fun!   

This post was written by Laura Corbett.