I have not once in my life had a hangover. I am the envy of all my friends, they are disgusted when I wake up the morning after the night before all perky and bright while they are stuck nursing a stonking headache in bed or puking in the toilet bowl. It is not that I don’t drink, I am more than partial to a gin and tonic or five, a bottle of beer, glass bottle of wine etc, it is just that I have never once felt the after effects of a boozy night out. I have wondered for a long time about why I don’t get them and why others do, so I thought I would do some digging around and find out.

Hangovers are a result of many factors, with dehydration being high on that list due to ethanol (alcohol) being a diuretic which causes increased urine production.  The effects of dehydration include headaches, a dry mouth and tiredness. This can be counteracted by drinking plenty of water but often when we are a little tipsy we forget to drink water, preferring yet another margarita. Alternatively, ethanol can be toxic at higher levels and some say that this toxicity causes damage to the stomach lining which results in the nausea. Headaches can also be the result of alcohol being a vaso-dilator. This means that it causes the blood vessels in the body to dilate which can results in reddening of the face and painful headaches. Alcohol also causes a reduction in blood sugar levels which interferes with the generation of glucose by the liver and this can result in tiredness and dizziness.

Ethanol, however, is not the only reason for your hangovers, acetaldehyde is also thought to play its part. Acetaldehyde is known to form adducts with cell proteins which can lead to cell damage (Eur. J. Clin. Pharmacol. 1991, 40,187-188).

Alcohol is detoxified and eliminated primarily in the liver via a series of oxidative metabolic reactions. The three major steps are:

(1) reversible oxidation of ethanol to acetaldehyde, which is an acute toxin according to the MSDS.

(2) non-reversible metabolism of the toxic acetaldehyde to acetate

(3) breakdown of acetate to water and carbon dioxide

An excellent article by de la Monte describes in detail the issues with alcohol consumption and, therefore, acetaldehyde accumulation. (Oxid. Med. Cell Longev., 2010, 3, 3, 178-185).

The article demonstrates that alcohol dehydrogenase  (ADH) is the main alcohol oxidizing enzyme and breaks down ethanol in the cytoplasm. Cytochrome P450 2E1 is employed by a distinct pathway that is induced by alcohol consumption  and results in acetaldehyde formation. The second step, primarily carried out by mitochondrial aldehyde dehydrogenase (ALDH), is the metabolism of acetaldehyde to acetate. The resulting acetate is unstable and spontaneously breaks down to water and CO_2. These oxidative mechanisms can become inundated which can result in toxic acetaldehyde accumulation. Disturbingly, experimental animal models have provided evidence that alcohol is a mutagen and that acetaldehyde is a carcinogen due to direct interaction with DNA and proteins. (H. Seitz, P. Becker, Alcohol Res. Health, 2007, 30, 38-41; D. Tuma, C. Casey, Alcohol. Res. Health, 2003; 27, 285-289)

The reason some us, including me, don’t get hangovers is because of polymorphisms in the ADH and ALDH genes. These can affect the rates of acetaldehyde generation and metabolism, and therefore change how much a person is prone to acetaldehyde toxicity.

Other impurities, such as methanol, can also be the cause of hangovers and these are a result of the alcohol fermentation process. These impurities are called congeners. The greatest amounts of these toxins are found in red wine and dark spirits such as bourbon. White wine and white spirits such as vodka contain less congeners and so in theory should give you less of a hangover. Buying more expensive alcohol should reduce the likelihood of these congeners since they should be distilled more rigorously. Different alcoholic drinks have different congeners and combining the range of impurities can result in a particularly bad hangover the next morning.

There are thought to be many other factors that contribute to hangovers including tannins in red wine and flavourings in dark beers. I mainly drink gin (a clear spirit) and tonic which may be another reason why I don’t get hangovers, although, conversely, I drink red wine in the bucket load which contains tannins and higher levels of congeners.

I hope you have learnt something about your hangovers and maybe how to reduce them with your choice of beverage. Feel free to leave any comments about your hangovers and what booze causes your affliction.