Social media and expensive home-testing kits are behind an increase in people self-diagnosing with food intolerances, dieticians have warned.
More than half of food intolerances, which are less serious than allergies, have been diagnosed without the help of a medical professional, research shows.
Experts have said that this could lead to people cutting out food such as dairy or wheat unnecessarily, depriving themselves of vital nutrients.
One in four adults said that they had an intolerance or allergy to certain foods, with nuts and gluten the most common problems named, in a survey of 1,033 by Ipsos. Nuts and gluten were the most common problems named.
While the majority of those with an allergy had been clinically diagnosed by a doctor, most people with intolerances had diagnosed themselves.
Some 39 per cent of people reporting an intolerance said that they had diagnosed themself by researching symptoms, usually via Google, ChatGPT or social media. A further 19 per cent had purchased home-testing kits, which experts have said are not accurate or reliable despite costing up to £400.
Only 31 per cent of people with an intolerance had been clinically diagnosed by a GP, doctor or healthcare professional.
Dieticians fear that social media is fuelling the idea that certain foods such as gluten are “inherently harmful” and responsible for symptoms such as bloating or nausea. Other factors such as stress, hormonal changes or irritable bowel syndrome could be to blame instead.
They warned that this has led to a growing number of people, including children, cutting out entire food groups, which can be harmful and deprive them of vital nutrients.
Allergic reactions happen when the immune system “overreacts” to a harmless food such as peanuts, milk or eggs, and sees it as a threat. This can lead to life-threatening symptoms, including anaphylactic shock.
Intolerances do not involve the immune system and are not life-threatening. They occur when the digestive system struggles to digest a specific food, which can cause gut symptoms such as cramping, bloating or diarrhoea.
The number of people who report that they have a gluten intolerance is on the rise
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The Ipsos survey showed that intolerances have become more common than allergies for certain foods. For example, 4 per cent of the population said they had a gluten intolerance, while only 2 per cent said they had a gluten allergy, known as coeliac disease. Similarly, 1 per cent had a milk allergy, while 4 per cent were lactose intolerant.
Lucy Upton, a paediatric dietitian and spokeswoman for the British Dietetic Association, said: “There has definitely been a trend of more people self-diagnosing with food intolerances over the past ten years. We are starting to see that in children as well, parents looking for answers, sometimes diagnosing using ChatGPT.”
She said it was particularly concerning if children cut out foods as it meant “this child is not getting enough of the right nutrition … it might impact their development”.
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There is no validated test for intolerances. Upton said it was vital that anyone who thought they had an intolerance worked with a dietician or doctor to investigate their symptoms. “People are buying things like intolerance tests online because they want an immediate answer,” she said. “It’s such a shame because these online intolerance tests are not validated. If they worked, we would use them in clinical practice.”
The NHS urges people to avoid at-home intolerance tests, which involve taking a pinprick blood sample, saying there is “limited evidence they give accurate results”.
The gold standard of diagnosing intolerances is removing certain foods over several weeks and seeing if symptoms improve, then reintroducing it to confirm that it causes symptoms.
Dr Federica Amati, the head nutritionist at ZOE, and nutrition lead at Imperial College London, said: “A number of forces are driving the rise in self-diagnosis of food intolerances. Greater public awareness of gut health, the influence of social media, and easy access to online health content and home-testing kits have all played a role.
“Unfortunately, marketing and social platforms have also fuelled the idea that foods such as gluten are inherently harmful, often without robust scientific evidence, and have positioned restrictive diets as ‘healthier’ even when there is no medical reason to follow them. As a result, diets such as gluten-free eating are now frequently adopted for perceived benefits rather than clear, evidence-based indications.”
Dr Federica Amati
DAIN RHYS EVANS
She added: “Relying on self-diagnosis, symptom searches online, or commercial home-testing kits instead of seeking guidance from a qualified dietitian or allergy specialist carries real risks.
“These include misdiagnosis, unnecessary and overly restrictive eating patterns, increased health anxiety, and delays in identifying underlying conditions such as coeliac disease or inflammatory bowel disease. It’s important to highlight the importance of validated diagnostic pathways and professional oversight to prevent inappropriate management and avoid nutritional harm.”
Amati said that labelling entire food groups as universally bad could have unintended consequences, including nutritional deficiencies, a higher risk of eating disorders, and negative psychological effects. “Gluten-free diets, for example, are often lower in fibre, B vitamins and other key nutrients, and may also increase food costs and contribute to social isolation.”
She said that people should not follow “elimination diets” and cut out whole food groups unless they have been assessed by a trained dietitian, allergist or registered nutritionist.
