Are you allergic or intolerant to alcohol?
Do you suffer from terrible hangovers or feel unwell after drinking just a small amount of alcohol? You may be intolerant – or even allergic – to alcoholic drinks. Sue Quinn explores the telltale signs of intolerances and allergies, the difference between them and what to do if you think you're affected.
What we understand as a 'hangover' is made up of a particular set of symptoms – usually a thumping headache, nausea, intense thirst, tiredness and brain fog. This is all happens as a result of drinking alcohol, or more specifically, the series of bodily processes it sets in motion.
Alcohol is toxic and must be converted by the body into non-toxic substances. This takes time, which is why the symptoms can last for a whole day or more. The length and severity of hangovers can vary, depending not just on the strength and quantity of alcohol consumed, but also the rate our body can process it at, which varies from person to person.
Dehydration is a key component of a hangover, as it can be responsible for many of the other typical symptoms, from headaches and fatigue to anxiety and sensitivity to light and sound, says Dr Timothy Watts, a consultant physician in adult allergy at The London Clinic.
Genetic Intolerance
Anyone who drinks in excess will likely experience these adverse effects to some extent. People who have an intolerance to alcohol, though, often suffer from particularly severe hangover-like symptoms due to a genetic metabolic disorder which “causes the body to process or metabolise alcohol incorrectly,” Dr Watts says.
When we drink alcohol, an enzyme in our bodies called alcohol dehydrogenase (ADH) breaks it down into a compound called acetaldehyde. Another enzyme, aldehyde dehydrogenase (ALDH), then turns acetaldehyde into non-toxic acetic acid (vinegar).
Older adults have less than average ALDH, which explains why our response to alcohol seems to worsen as we age. But those with a genetic intolerance have a mutated version of ALDH, says Dr Watts. “The mutation in this crucial enzyme leads to the accumulation of acetaldehyde in the body, and then various unpleasant symptoms. Typically, these include extensive skin flushing and other features such as nausea, vomiting, palpitations, headache and fatigue.”
Research suggests this is one of the most common hereditary disorders in the world, affecting 560 million people, or eight percent of the global population. The highest prevalence (35-40 percent) is among in people of East Asian descent.
Other types of intolerance
In other cases, people can be intolerant to the chemicals that give alcoholic drinks their flavour and colour, not the alcohol itself. Histamine (found in red wine) and salicylates (found in wine, beer, rum, and sherry), are common examples.
Some people are intolerant to the preservatives in alcohol called sulphites, and find that consuming them can trigger symptoms including a stuffy or runny nose, bad headache, hives, itchiness, wheezing and tummy upset.
Research suggests that up to 10 percent of asthmatics are sensitive to sulphites, with the severity of reactions varying from mild to life-threatening. “The wheezing and nasal/sinus symptoms in particular are due to the release of sulphur dioxide gas causing airway irritation,” Dr Watts explains.
Alcoholic drinks high in sulphites and/or histamine include wine (red, white, rosé and sparkling), cider and beer. Some varieties of gin and vodka, as well as ‘natural wines’ are low in sulphites. However, asthma experts warn sufferers to choose their drinks carefully, because even low-sulphite wines will contain some sulphites.
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Alcohol allergies
“A true allergy to alcohol is rare,” says Dr Fiona Sim, chief medical adviser for alcohol charity Drinkaware. “Rather than alcohol itself, a person is much more likely to be allergic to one of the ingredients in their alcoholic drink, such as wheat, barley or another grain.”
Another type of allergen, lipid transfer protein (LTP), is found in fruits, vegetables, nuts, seeds and cereals, and can also be present in some alcoholic drinks.
Symptoms of an allergic reaction to LTP usually appear within 15-30 minutes and include swelling, itchiness, digestive problems, breathing difficulties and, in extreme cases, anaphylaxis. LTP is not destroyed by heat.
“LTP allergy is an increasingly recognised cause of food allergy in the UK, certainly in the last five years,” Dr Watts says. “Alcoholic drinks can be the trigger for reactions in some cases, alongside other food groups.”
It’s very difficult for consumers to know whether an alcoholic drink contains allergens or ingredients they’re intolerant to. That’s because in the UK, alcoholic drinks manufacturers don’t have to put an ingredients list or nutrition information on the label. So, Dr Sim urges anyone who knows they’re allergic to certain foods, particularly grains, to be aware they could be in drinks, too.
“This is a hazard that should be recognised. Someone with a serious allergy, which can be life-threatening, may be best advised to request the ingredients of a drink from the manufacturer before trying it.” This is particularly important if you drink cocktails or other mixed drinks, which will have large and varied lists of components: “Think about all of the ingredients in order to avoid anything to which you are allergic.”
Alcoholic drinks can also trigger an allergic reaction to food if you consume the two together, as alcohol can interfere with the gut lining. For example, someone with a wheat allergy may only react after eating wheat followed by drinking alcohol or exercising. “This is known as food-dependant cofactor induced anaphylaxis,” Dr Watts says.
Cooking with alcohol
Many savoury and sweet recipes contain alcohol, including red wine-based stews and casseroles, and liqueur-laden puddings. Is it OK to eat them if you have an alcohol intolerance or allergy?
“Alcohol and sulphites tend to evaporate away during cooking, so the potential for intolerances is certainly reduced,” Dr Watts says. However, if you’re allergic to an ingredient found in certain alcoholic drinks, dishes which contain that drink are not safe to eat.
Advice
It’s relatively simple to recognise the difference between a hangover and an alcohol intolerance, Dr Watts says. “Hangovers are usually in full effect the morning after a night of heavy drinking. Metabolic genetic intolerances, however, happen more quickly, generally within an hour of drinking.”
It’s harder to distinguish between an intolerance and an allergy, because the symptoms can overlap. Some allergic reactions are almost instant, but not all. “If in any doubt, always consult a healthcare professional,” Dr Watts says. “Investigations for alcohol reactions normally consist of specialised allergy blood tests, skin prick tests and potentially even a food challenge.”
Dr Sim advises those with any type of intolerance to alcohol to avoid drinking it altogether, “although many people are willing to put up with the discomfort of skin flushing and perhaps mild abdominal symptoms in order to continue to have an occasional alcoholic drink,” she admits.
It’s especially important to not drink alcohol if you have a genetic intolerance, as it will “increase your risk of alcohol-related organ damage, including some cancers and liver disease.”
When it comes to allergies to any component of an alcoholic drink, you must never consume it. “It can be life-threatening,” Dr Sim says.
Originally published August 2022.
