Do You Really Have A Food Intolerance?

First – what’s the difference between an allergy and an intolerance? 

There’s a big difference, says Dr Natalie Direkze, consultant gastroenterologist of OneWelbeck. “A food allergy occurs when the body develops an immune response to a particular food, and this can occur with even tiny amounts of that specific food. An example of this is a nut allergy, when even tiny amounts of nuts can cause a severe, often immediate, immune reaction which can in some cases prove fatal.” A food intolerance, on the other hand, happens when the body struggles to digest a particular food, Natalie explains. “You may get symptoms, but an intolerance is not as severe as an allergy. A person with an intolerance may tolerate small amounts of the food in question with no problem, but larger amounts are more likely to cause symptoms.” The other main difference, says Dr. Shabir Daya, pharmacist and co-founder of Victoria Health, is that the reaction to an allergy is immediate, while food intolerances take longer to manifest. “In some instances, there may be a delayed reaction as long as 48 hours,” he says.

Have food intolerances really increased in recent years? 

You’d be forgiven for thinking we’re a nation riddled with food intolerances, with sales of free-from foods having trebled in the last three years. But are intolerances really on the rise? The evidence isn’t so clear-cut, and the experts remain divided. “Levels of food intolerances have increased over the last two decades and this is not simply because we are more aware or better at diagnosing them,” says Shabir. “It’s thought that the reasons behind a rise in intolerances is linked to our lifestyles, diet and environment.” Natalie, however, believes the rise is down to increased awareness around food and increased testing, notably tests to assess the causes of common gut symptoms. “Several reports suggest food intolerances affect less than 2% of British adults, although 20-30% believe they have some form of intolerance,” she says. Nonetheless, it’s not to say intolerances to substances such as gluten don’t exist – studies show around 13% of British adults experience symptoms when they eat gluten-containing foods, yet only 0.8% of the population has been formally diagnosed with coeliac disease. 

What are the most common food intolerances?  

“Dairy, wheat and foods containing fermentable sugars, such as onions, garlic and beans, are among the most common foods people claim to be intolerant to,” Natalie explains. However, the experts also say there are other less obvious foods, which may trigger a sensitivity in some people. Take nightshades, for example, a plant group that consists of tomatoes, peppers, aubergine and potatoes, which can be inflammatory for some people. Egg whites also contain a protein, which can cause problems if you have leaky gut syndrome, while the roughage of nuts can irritate some people. Yeast – found in bread, baked products and alcohol – is also a common intolerance. Shabir also says tea, coffee and citrus fruits can be inflammatory, too.

What are the signs you may have an intolerance? 

Given an intolerance arises when a food isn’t properly digested, it makes sense that symptoms are often related to the gut. As the food in question begins to ferment in the gut, it’s common to experience abdominal discomfort. “The commonest symptoms of a food intolerance include bloating and diarrhoea that start a few hours after eating a specific food and tend to be worse the more of the food you eat. On the other hand, if you have an allergy, symptoms can include tingling around the mouth with swelling, wheezing and difficulty breathing. These symptoms always need emergency medical attention,” Natalie says. Skin rashes and itching are also common signs of an intolerance.

Is it possible to suddenly develop an intolerance? 

Yes, says Natalie, especially if you’ve been unwell. “Some people develop a food intolerance after an episode of gastroenteritis, with dairy being something that people struggle with after a bout of illness.” Shabir agrees, saying it’s not uncommon to develop an intolerance as you get older. “They can be triggered by a stressful event such as starting a new job, childbirth, stress and perhaps overuse of antibiotics."

How can you get tested for a food intolerance? 

First – don’t be lured by Instagram ads of at-home intolerance tests. At present, there is no regulation of food intolerance testing in the UK, so many of the products out there have zero science behind them. “Having dealt with patients with severe malnutrition after undertaking diets based on some of these tests, I am very wary of them and am not clear on the evidence underlying their use,” Natalie warns. “If you have severe or concerning symptoms related to food, especially if they are new or progressive, you need to ensure you seek medical advice,” she advises. While a dietitian is your best port of call, not everyone has the budget for one-on-one expert advice, so it could be worth trying an elimination diet, especially if your symptoms are mild, Natalie says.