A CRAZE which involves having your blood tested to see which foods you might be ‘hyper sensitive’ to, is surging in popularity.

In recent weeks Geordie Shore’s Gaz Beadle, 30, from Prudhoe, Northumberland, and Holly Hagan, 26, from Thornaby, have jumped on the bandwagon, urging their North-East followers to do the same.

Holly told her Instagram fans that identifying her food intolerances had helped to combat poor skin, saying: “These breakouts were horrific all over my face and chest and I just couldn’t work out what I was doing wrong.

“My mam noticed that I eat pretty much the same thing every day – one being poached eggs – she thought maybe it was a reaction to something I was eating. She was right I was intolerant to eggs, cow’s milk, peanuts.

“From that day I cut out eggs and peanut butter and reduced my intake of wheat and yeast as that was a mild intolerance and my skin has completely cleared. This is not sponsored and I’m not being paid to say this but hopefully if someone out there is suffering like I was this could help.”

Other stars to do the same include Made in Chelsea’s Lucy Watson and Louise Thompson, as well as Olympian Sally Gunnell and model Danielle Lloyd.

But how does it all work, and why are so many people jumping on the intolerance bandwagon?

Dr Gill Hart, of leading food intolerance testing specialists YorkTest Laboratories, headquartered in York, answers some important questions:

What is a food intolerance?

Dr Hart: A food intolerance is essentially someone experiencing reactions to certain foods. Classic symptoms include things like IBS (irritable bowel syndrome), regular bloating or feeling like you have lots of gas, as well as diarrhoea, constipation or abdominal cramps. Things like migraines and headaches, tiredness, especially chronic fatigue, low mood, depression, anxiety, can also be signs of something wrong, as can skin problems such as eczema and psoriasis. And it’s more common than people realise. A recent survey, conducted by us, showed a fifth of Brits – 19 per cent – believed they had food intolerance, with bloating being the most common complaint.

Is an ‘intolerance’ the same as an ‘allergy’?

Dr Hart: Absolutely not. Food allergies are pretty rare, affecting just two per cent of the adult population. During an allergic reaction, the body’s immune system believes it is being ‘invaded’ and produces IgE (Immunoglobulin E) antibodies to fight off the food or drink ingredient it mistakenly considers to be harmful. The body’s inflammatory response kicks into gear quickly, and in extreme cases it can result in a reaction called ‘anaphylaxis’, which is potentially fatal. With intolerances, however, you typically see a delayed biological reaction which, although often uncomfortable and unpleasant, is not life threatening.

What does the blood test look for?

Dr Hart: When food particles enter the bloodstream, the immune system can sometimes identify these food protein particles as “foreign” and produces what’s known as ‘IgG antibodies’ to ‘attack’ the food in question. This response is your immune system’s natural defence mechanism to ward off harmful invaders in the body which can create inflammation. So, essentially, these IgG reactions go hand in hand with gut imbalances and inflammation and are released in the presence of certain ‘trigger’ foods. And by monitoring which foods cause food-specific IgG reactions, we can advise people on what they might wish to cut from their diet.

Is something fuelling a rise in food intolerances?

Dr Hart: It’s my belief that increases in stress, antibiotics, painkillers and processed food are all making food intolerances more common than ever. You have good bacteria protecting your gut and protecting your immune system. But antibiotics knock out both your good bacteria and your bad bacteria. Processed food can also damage your gut, particularly additives found in things like bread. Meanwhile stress also plays an enormous role. Eating on the hoof, not chewing your food properly, means your gut is suddenly bombarded with food that hasn’t been properly broken down. Modern lifestyles are contributing to the problem.

What intolerances are most common?

Dr Hart: We see a really diverse array of food intolerances, from carrots and wine grapes through to beef. It’s also really important to look at the ingredients that go into foods. We see people react to corn, for example. People might think, ‘Well, I don’t eat much corn on the cob or tinned sweetcorn, so it’s easy for me to remove it from my diet’. You have to remember that things like tortilla chips, tacos and enchiladas are all made from corn flour, and corn is also used to manufacture things like fructose, cereal starch and vegetable oil. For us, it’s about advising people to look at the wider picture.

What happens once I get my test results?

Dr Hart: Food intolerance test results shouldn’t be seen as a ‘diagnosis’, but simply a ‘food road map’, giving you an accurate guide to your optimal diet. It overrides the guesswork on what works for and against your body. But you should always seek a programme that includes nutritional support that includes personalised guidance on replacing eliminated foods with nutritious alternatives. This is especially important for children.

What’s the controversy about food intolerance testing?

Dr Hart: The controversy arises from food intolerance tests that have no basis in science, such as hair tests. It also arises from tests that do not provide evidence to show that their results are effective. But it’s our view that the IgG levels we see are caused a direct result of an intolerance, and that they’re a vital tool in improving the lives of a great many who suffer with gut problems.

Can children take a food intolerance test?

Dr Hart: Yes they can, but again, it’s important to see a GP initially if you’re feeling unwell to rule-out any other underlying conditions. It is important to receive guidance on how to replace the nutrients of the foods you will be missing, as well as how best to repair any damage done to your gut, especially with a child’s diet. It is essential that they are still receiving the same amount of nutrients without their trigger foods.

What should you look out for in a test programme?

Dr Hart: You’ll come across many different types of food intolerance tests online. There is currently no regulation for home food intolerance tests, so it is important you seek a reputable provider and make sure to do your research before placing your order. Look for a CE marked test that meets the requirements of European Directives, an accredited laboratory that is independently audited.