Hungover, allergic or intolerant? Get savvy with alcohol choices

By The Gut Health Doctor Team

Dr Megan Rossi in a lab looking through a microscope

Does one glass of wine leave you feeling frightful the next day, while your friends can enjoy half a bottle and wake up fresh? If so, you may be wondering why you, and what’s the answer to enjoying alcohol without the pain? 

We’re here to help you identify your potential triggers, harness the power of your gut microbes and get savvier with your choices.

First up, could it be an allergy?

If alcohol leaves you feeling instantly ill, you may wonder whether an allergy to alcohol is to blame. Although it is not uncommon to experience allergy-like symptoms to alcohol (remember an allergy involves the immune system, whereas an intolerance doesn’t), a true allergy to alcohol is actually very rare and, with symptoms such as difficulty breathing and abdominal pain, you’d be unlikely to touch another drop.

Could your genes be to blame for an alcohol intolerance?

More common than alcohol allergies are intolerances. Firstly, let’s take a look at how the liver actually processes alcohol and if your genes could be to blame:

  • Your liver breaks alcohol down into acetaldehyde
  • At this point, an enzyme called aldehyde dehydrogenase should then break the acetaldehyde down into acetic acid – the main component in everyday vinegar
  • Some of us have a less active form of this enzyme, due to a genetic fault
  • In these cases, acetaldehyde can linger, triggering vomiting, nausea and headaches as the body tries to expel it  
  • It can also cause the blood vessels to widen, leading to facial flushing and a stuffy nose.

If this is you then the only way around this is to learn your limits: make sure you start small (perhaps with half a unit), as some people can even struggle with a few sips. 

Intolerant to specific components of alcohol?

What’s more likely than a general alcohol intolerance is that you have an intolerance to, or issue with, a component of the specific alcohol you drink. In such cases making a more informed decision about your choice of drink may save the day. 

Three pints of lager on a table to demonstrate gluten in alcohol intolerance

Grappling with gluten

If you know that you struggle with gluten in foods, then it could be the gluten in beers, lagers and ales that are giving you jip. If you feel more comfortable after tipples like spirits, wines and cider, which are gluten-free, then you may have found your trigger (check out our blog on Coeliac disease). Just remember to check those alternatives for any added ingredients. 

Three glasses of white wine on a table to demonstrate sulphite in alcohol intolerance

Sulphite sensitivities

If wine leaves you with a stuffy nose, wheezing, hives and bad hangovers, then sulphites might be the culprit here. A 2019 study found that switching to organic wine led to fewer headaches for those with sulphite sensitivities. While organic wines do still have sulphites from grapes, they won’t have some added sulphites you might otherwise find in other brands, so give that a go and see if it’s easier to tolerate. 

Two glasses of red wine on a table to demonstrate histamines in alcohol intolerance

Hindered by histamines

Histamine is a chemical produced as part of the fermentation process — you’ll find it in beer, wine and spirits. If you suffer from a hot, red face, hives, nausea or diarrhoea when drinking, then it could be a reaction to the histamines. There are generally higher levels in red wine than in white, so try switching for a glass of Sauvignon Blanc – if there is less of a reaction than usual, it might be worth exploring an intolerance to histamines. Need help with a histamine intolerance? Book in with one of our specialist dietitians.

How to hold off hangovers

If you’ve managed to rule out all the above as the cause of your headaches, there are other reasons that you could be more susceptible than others to the negative effects of alcohol. The good news? There is something you can do about it! 

Photo of two glasses of champagne within a party (alcohol blog)

Banish the bubbles

A champagne toast at a wedding or prosecco at a garden party – the clink of a glass full of fizz can summon the sound of sunny days, but it’s good to know that anything with bubbles is likely to make you feel worse.

This is no old wives’ tale. Researchers from the HPRU Medical Research Centre in Guildford put this to the test by giving volunteers fizzy or flat champagne. Those given the fizz got drunk more quickly. That’s because the bubbles cause the alcohol to be more rapidly absorbed into your bloodstream and overtake your liver’s ability to digest it at such speed. The higher your blood alcohol concentration… the more toxic the impact on your body.

Photo of two different kinds of alcohol mixers in a party setting

Choose your mixers carefully

Be cautious of mixers containing artificial sweeteners. A 2015 study from Northern Kentucky University found that if you drank vodka and diet soda or vodka and regular soda, the ‘diet’ version actually led to a 25% higher blood alcohol concentration. This is because the sugar slowed the alcohol absorption through the stomach (of course, a high-fibre meal would do this even better). Try switching out the sugary soda for soda water and alternate every other drink with a non-alcoholic option: our favourites include sparkling water with frozen berries or traditional kombucha (not the supermarket bought ‘fake’ types).

Photo of lots of whole foods (banana, oats, spinach) to reflect fibre diversity

Eat well before, during and after

As always, look after your gut microbes! Prepping your gut with extra fibre before, during and after your night out is crucial to arming your microbes with the tools to support your gut-liver axis. Excess alcohol can have a negative impact on your microbes, especially those higher up the gut, where alcohol is absorbed. This impedes their production of the short chain fatty acids, such as butyrate, that help fuel the protective gut lining.

Because alcohol itself can also irritate and weaken our gut wall, toxins can more easily pass from our gut into our bloodstream, creating more inflammation (which may lead to the release of histamines). The result? You feel rough. But if your gut microbes are in good shape, they’re more likely to produce more butyrate, which may well help the body better withstand the inflammatory effects of alcohol.

The day before the party make sure you eat a good meal, like our gut-loving Greek baked beans. These provide the ideal mix of plant diversity, such as prebiotics (plant compounds that are microbe fertilisers) for your gut microbes to feast on. They may even satisfy those salty and carby hangover cravings the next day! And don’t forget to prioritise eating food when you’re drinking in order to slow the absorption of alcohol and give your liver a chance to keep up.


There are a lot of things at play when it comes to feeling ill after drinking alcohol, and everybody can be impacted differently. But if you are aware of the differences in what you’re drinking then it can help you make better choices and, hopefully, feel better.

Also keep in mind that a helpful starting point is preparing your gut health. A diet rich in diversity (aiming for 30 plant points a week) will be your best friend when it comes to fighting the negative effects of alcohol.

If the worst happens and you do wake up with a hangover, the key is hydration. While good old water will do the trick, you could also try an electrolyte drink, which contains salts such as potassium and may help you better absorb fluid while you rehydrate (particularly if you are suffering from diarrhoea or vomiting).

And as much as this advice can help, remember that there’s no better way to avoid a hangover than to not drink, or at least drink responsibly. If you are having any issues with alcohol be sure to contact your GP or check out drinkaware.


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