Wednesday October 9 2013
Researchers tested 57 drinks as potential hangover cures
"Best cure for a hangover? Sprite," claims The Daily Telegraph and the Mail Online. But the popular fizzy lemon and lime drink may not be the morning-after quick-fix for boozers that the media suggests it is.
The headlines are based on a Chinese laboratory study that measured the effect of different drinks on the speed liver enzymes metabolise alcohol. Out of 57 drinks tested, researchers found that only two drinks increased the speed of two liver enzymes that reduce the amount of the toxic chemical acetaldehyde. This chemical is produced when our bodies break down alcohol.
The first drink was called "hui yi su da shui" (probably a type of soda water) and the second was called "xue bi" (probably Sprite, although the study did not report that either of these drinks were the popular drink known as Sprite).
The researchers did not measure the effect of these different drinks on people with hangovers, as the study was conducted in a laboratory. Therefore, it is not clear what effects, if any, these drinks have on these enzymes in the body, or on a hangover. The best way to "cure" a hangover is to avoid drinking excessive amounts of alcohol, although rehydration also plays a part, so soft drinks may logically have some benefit.
The advice remains to keep within the government guidelines of drinking no more than 21 units per week for women and 28 units for men, and not to "binge drink", which is having more than six units of alcohol a day for women and eight units a day for men.
Where did the story come from?
The study was carried out by researchers from Guangdong Provincial Key Laboratory of Food, Sun Yat-Sen University, China and no external funding was reported. It was published in the peer-reviewed medical journal, Food and Function.
The media has not reported this study accurately – The Daily Telegraph reported that the carbonated drink speeds up "the first process" of breaking down alcohol, when it actually reduces the first part of the process and speeds up the second, more crucial process. The Mail Online unhelpfully suggests, "good news … as we age our brains shrink, so there is more room for it to swell before it hits the bone".
In general, the media has reported this study from the perspective of wanting an easy fix for a hangover, rather than highlighting the detrimental effects of excessive drinking. There is also some confusion about the type of carbonated drink involved in the research.
The claim is likely to have received media attention after Chemistry World, the magazine of the Royal Society of Chemistry, published a news article about the study, naming Sprite as the drink of choice. The Royal Society of Chemistry also publishes Food and Function.
What kind of research was this?
This was a laboratory experiment that looked at the effect of 57 different drinks on the speed two liver enzymes metabolised alcohol and its waste product acetaldehyde.
It aimed to gather evidence about the effects of these drinks on the two enzymes, which are called ADH and ALDH. It was not designed to determine if the consumption of these drinks with or after alcohol would affect its metabolism in humans.
A randomised controlled trial would be required in humans to determine the effect of different drinks on alcohol in terms of the level of intoxication and severity of hangovers. However, this would be unethical as it would expose participants to harmful levels of alcohol. Studies in people who developed a hangover of their own free will may be possible, though.
What did the research involve?
Ethanol is the type of alcohol found in alcoholic drinks. It is broken down (metabolised) by the liver before it leaves the body. It is first metabolised by the liver enzyme alcohol dehydrogenase (ADH) to produce a chemical called acetaldehyde.
It is believed that acetaldehyde may cause many of the damaging effects of ethanol to the body, such as hangovers. The acetaldehyde is then metabolised by a second liver enzyme called acetaldehyde dehydrogenase (ALDH) to become a chemical called acetate, which is less harmful.
The researchers wanted to see whether different drinks might increase or decrease the speed at which these two enzymes worked. They aimed to see if these drinks could potentially reduce the time the body would be exposed to the damaging chemical acetaldehyde.
The researchers tested 57 drinks, including 40 herbal infusions, 12 kinds of tea and five types of carbonated drinks. They added each drink to two different mixtures in the lab:
- ethanol and alcohol dehydrogenase (ADH)
- acetaldehyde and acetaldehyde dehydrogenase (ALDH)
The researchers measured how quickly the ethanol and acetaldehyde were broken down immediately and again after 15 minutes, comparing the effects with control samples that did not have any of the test drinks added. They performed the trial three times for each drink and took an average result.
What were the basic results?
Only one drink slightly reduced the activity of ADH in metabolising ethanol and increased the activity of ALDH by 49%, causing the levels of the toxic chemical acetaldehyde to lower quickly. This drink was called "hui yi su da shui" (which may be translated as Should Benefit Soda Water – see box), which the researchers report is a "kind of weak alkali soda drink which contains some flavour additives and sugar". They did not know which chemical in this drink may be responsible for the changes seen.
Four drinks slightly increased the activity of both enzymes, one increasing the activity of ALDH in getting rid of acetaldehyde by 28%. This drink is called "xue bi", which is likely to be the well-known lemon and lime fizzy drink, Sprite.
There were 21 drinks that increased the metabolism of ethanol but reduced the metabolism of acetaldehyde, and 31 that reduced both, including green tea.
How did the researchers interpret the results?
The researchers concluded that, "2 of 57 beverages studied, xue bi and hui yi su da shui, are suitable for drinking for humans with excessive alcohol consumption".
The study has used laboratory experiments to predict what might happen when drinking alcohol with other beverages, in terms of whether the intoxicating effects of alcohol are increased or if the symptoms of a hangover are reduced. The experiments looked at the speed ethanol was metabolised and the first toxic waste product that is produced in its breakdown, acetaldehyde.
While the findings are interesting – that only 2 of the 57 drinks reduced the amount of time it took to metabolise acetaldehyde – this is only one aspect of the negative effects of alcohol, and occurred in dishes in a laboratory, not in people.
The symptoms of hangovers are probably caused by a combination of the level of ethanol, acetaldehyde and other substances within the alcoholic drink (called congeners) and the effects of alcohol on the body, including:
- low blood sugar
- disrupted hormone levels, such as cortisol
It is not possible to say with certainty that either of the drinks identified as having the desired effects in the lab would have any effect on hangovers in people. The best way to avoid a hangover is to limit the amount of alcohol drunk in the first place.
Alcohol is damaging – it causes intoxication, which puts people at risk of accidents and placing themselves in vulnerable situations, and in the long-term is associated with liver cirrhosis and cancer.
The advice remains to keep within the government guidelines of drinking no more than 21 units per week for women and 28 units for men, and not to "binge drink" (drinking more than six units a day for women and eight units a day for men).
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.