Last month, wellness genetics company DNAFit released the results of a survey that showed almost half (45%) of British adults now believe they have a food intolerance, despite the fact that only 15% have an official diagnosis. So commonplace is our tendency to turn doctor and diagnose ourselves as lactose-intolerant or allergic to wheat that the researchers have given it a name: ‘nutrochondria’ is, it says, “the preoccupation with negative details of one’s diet and a propensity to self-diagnose food intolerances or allergies based on supposition or flawed evidence”. It explains why in the 12 months leading up to summer 2017, the UK’s ‘free from’ food industry grew by 40% to an estimated £806m. As our perceived dietary sensitivities have become more pronounced, the food industry has rushed to fulfill our increasingly restricted ‘needs’. Gluten-free Cornetto, anyone? We’ve become a nation of intolerant eaters. But with so few of us getting diagnosed, could this epidemic be all in our heads? 

Intolerant or sensitive?

Dr Claudia Gravaghi, a nutritionist, pharmacist and scientist at Doctify (a platform that helps patients find local medical specialists), points out that although people often use the terms ‘intolerance’ and ‘allergy’ interchangeably, they’re very different. “An allergy is where the immune system recognises a certain food as a threat and releases antibodies to fight that substance. Even a tiny trace may cause reactions – eczema or rashes, itching, vomiting, diarrhoea, nausea, tongue or lip swelling, and heart palpitations.” 

Extreme cases can be life-threatening. “An intolerance, on the other hand, doesn’t involve the immune system,” she continues. “This is all in the gut, when you lack an enzyme to sufficiently digest something that can result in bloating, wind, diarrhoea or stomach pain.” And as Dr Kevin Barrett, GP and chair of The Primary Care Society for Gastroenterology, points out, “Technically, a true intolerance, rather than an allergy, shouldn’t have any effect outside of the gut.” So if you’re getting a blotchy rash or an itchy throat, it’s likely that you’re not dealing with an intolerance. “The problem for doctors is that there could be a number of issues, which makes it hard to pinpoint what food is causing the discomfort.” 

There’s also a third and, Dr Gravaghi argues, more common category: food sensitivity. “It’s one that few people talk about, but I see it as distinct from the other two.” As with an allergy, having a ‘sensitivity’ to a certain food, such as dairy, eggs or nuts, will cause your immune system to release antibodies. These bind to the offending food proteins bobbing around in your bloodstream and can then, generally, be flushed out of your system by your immune cells. However, if the protein-antibody combinations are produced more quickly than your body is able to remove them – which happens if you eat a lot of the thing we’re sensitive to or your gut isn’t working properly – “they can form deposits in various tissues. This can cause joint pain, headache and brain fog,” Dr Gravaghi explains. 

It’s worth keeping in mind too that not having an official diagnosis doesn’t necessarily mean we’re fantasists. “I see dozens of patients every day who suspect they have a food intolerance, and although it’s complex to diagnose, that is often the problem,” says Dr Barrett. “Their symptoms are very real and, generally, instances of intolerance have been on the rise. It’s hard to say why exactly but it could come down to dietary changes – perhaps we’re eating a wider range of foods than we used to and our systems aren’t used to them. Or perhaps we’re eating too many processed foods and they’re disrupting our microbiome [more on this later]. “Either way, from a clinical perspective, dietary issues can be hard to diagnose accurately, or at all.” Which does in part account for the discrepancy between the number of people who think they have an intolerance and the number who are diagnosed.

While cutting dairy and gluten may seem a bit bandwagon-y, they are statistically the most likely culprits. Although they’re not the only ones, as pointed out by Helen West, dietitian and co-founder of The Rooted Project, an organisation that aims to dispel common food and diet myths. And it’s not a good idea to start snipping them out of your diet on a whim. Histamine intolerance is another common bugbear, and can cause headaches and a runny nose (high histamine foods include hard cheese and, sigh, red wine). Other gut and stomach problems have been linked to a group of foods classified under the acronym FODMAP. These short-chain carbohydrates aren’t digested properly by the body and instead sit in the large intestine, where they ferment – causing the production of gas, which can result in bloating. They include things such as onions, artichokes, raw beetroot and ripe bananas. “Lots of people will find they’re intolerant to a FODMAP food,” says West. “The trick is working out which one particularly. To start cutting them all out would restrict huge swathes of your diet.”  

Why the rise in ‘intolerance’?

To an extent, the fact more of us think we’re intolerant to some foods comes down to the bandwagon effect. “If you went back to pre-internet times, you would struggle to find someone with a food intolerance,” says Rick Miller, dietitian and nutrition manager for The a2 Milk Company, which produces a type of milk that’s more easily digestible for people with sensitive stomachs. “I’ve seen patients who’ve wrongly cut out entire food groups after reading about an intolerance online.” Many of us choose a gluten or dairy-free option as it seems like a shortcut to healthy eating. But according to a study from the University of Hertfordshire, most gluten-free products they tested typically contain more saturated fat, sugar and salt than regular food items, while also being lower in fibre and protein. Still, some scientists argue that millennia of crop manipulation and wheat breeding have created a type of wheat that is incredibly high in gluten, which is why more of us are claiming wheat sensitivity. While that may be true, it doesn’t account for the myriad other ‘intolerances’ that people are reporting. 

One of the most compelling arguments for why some foods are causing us to feel unwell is that we’re not properly cultivating our gut microbiome. This ecosystem of bacteria, fungi, viruses and yeasts lives in our intestinal tract. Part of its job is to break down foods so they can be properly digested (you’re said to have an intolerance when this isn’t happening). But it also keeps the intestinal walls impermeable so food-protein molecules don’t escape into the bloodstream. A healthy gut has a huge diversity of bacteria. But, as one study found, eating lots of highly processed foods could cut your microbiome diversity by 40% in as little as 10 days. 

If our microbiome isn’t working properly and food isn’t digested as it should be, we’re likely to experience those symptoms of intolerance, but, as Dr Barrett points out, “lots of people come to me with symptoms such as headaches and moodswings. They think they’re ‘intolerant’ to a certain food, but an intolerance generally presents as bloating, stomach pain, wind and constipation in the gut.” Problems with our microbiome, however, could mean the mucus layer protecting our intestinal walls forms holes. Then more proteins leak into our systems, our bodies struggle to clear these and they form those deposits around the body that lead to symptoms of food sensitivity (headaches, mood swings).

And it’s not just food: if the intestinal walls aren’t properly fortified, toxins can also get through. As neuroscientist Dr Mithu Storoni says in her book Stress- Proof, a steady leak of toxins could cause low-grade inflammation, which has been linked to chronic fatigue and depression. “Many so-called ‘clean’ diets may also be problematic,” she explains. “They are low in fibre, which is ultimately what your gut bacteria thrives on.” As Miller sums up: “Part of the reason this feels like an epidemic is because more people are talking about it now. Some may not have an intolerance but their microbiome isn’t functioning properly. Others might be misdiagnosing themselves; they might have IBS or a sensitivity. The first step for anyone who thinks they are intolerant is to make sure that it’s not something else.” 

Digestive Issues? 

First, don’t bother wasting money on saliva tests that claim they’ll diagnose your intolerance. Every expert we spoke to said they’re unreliable. “Blood tests can help in some instances, but an elimination diet, done with a doctor, is the way we’d work out what you’re intolerant to,” says Dr Barrett. “The truth is, you might be allergic or intolerant to a type of chemical food colouring – but it’s unlikely you’ll be able to spot that yourself, whereas a dietitian or doctor will.” And cutting food groups can have adverse effects. First, keep a diary of what you’re eating and the symptoms you’re seeing. “Make sure you’re accurate with the times of day you’ve eaten and when you experience symptoms – this can be a good indicator of what your condition is,” says West. Symptoms of an allergy come on quickly. If, like clockwork, you get an itchy throat 45 minutes after consuming something, it’s likely to be a mild allergy. 

“Different intolerances have different symptoms, so be clear about what exactly you’re feeling,” she continues. For example, histamine intolerance can cause a runny nose and headaches, while lactose intolerance causes bloating and diarrhoea; for a comprehensive list, check allergyuk.org. “If you’re seeing a clear pattern, try cutting that specific food for 2-4 weeks, then reintroduce it and see how you feel,” says West. “Though I’d still recommend showing your diary to a doctor in the meantime.” If your discomfort comes with a side of mood swings, anxiety or mild depression (and there is mounting evidence to show that there is a strong link between gut and mental health), then focus on cultivating your microbiome. “Try adding some fermented foods to every meal,” says Storoni. “It’ll improve the diversity of your gut bacteria. You could have a little live yogurt or some sauerkraut.” Otherwise, make sure you eat a wide range of vegetables (think ‘eat the rainbow’) and plenty of fibre (brown bread, wholewheat pasta, potatoes with skin on, nuts and seeds). And as for that dairy-free, gluten-free pizza? Well,if it tastes good, don’t let anyone stop you. 

“Am I allergic to fruit?”

Talent producer Kate Mander believes she’s allergic to kiwi, aubergine, pineapple and plums. She tried The Organic Pharmacy’s Health Assessment, £150 for 90 minutes (theorganicpharmacy.com)

 “I’ve had trouble with digestion since my 20s – cramps and bloating – and thought I was allergic to certain fruits, so I got tested by the NHS a few years ago. It confirmed I had a sensitivity but no underlying cause. For the test, straps were placed around my wrists, ankles and head while a bioenergetic device scanned my body for a multitude of things. Again, the results didn’t confirm an allergy, but did pick up that I shouldn’t eat fungal foods (mushrooms or blue cheese) and am sensitive to yeast, sugar, oranges, alcohol and gluten. All the fun things.” 

“I think I’m gluten intolerant”

Designer Vivien Ilett suspects she has a gluten sensitivity and intolerance to lactose. She had a consultation with Gabriela Peacock at Grace Belgravia, £250 for 1 hour (gracebelgravia.com)

“I get bloated and feel nauseous easily, especially if I have bread or pasta, but it often feels like anything can flare it up. Gabriela suggested that while I might have some sensitivity to gluten due to potentially having too much of it in the past, my gut bacteria levels might be the reason I was having sensitivity to almost all food groups. She advised me to stay away from wheat for 6-8 weeks so my gut lining has a chance to renew itself, then look into taking some probiotics to restore a more healthy bacterial balance.” 

“Do I have a wine sensitivity?”

Stylist editor Susan Riley suspects she has a sensitivity to wine. She took the YorkTest Food&DrinkScan Programme, from £299 (yorktest.com)

“Recently I’ve experienced a slight swelling of my lips after drinking wine. While this might sound like a simple allergic reaction, it crops up seemingly randomly, too. It makes me wonder if there’s an underlying component that I can’t quite put my finger on. I did a blood test that showed I have what’s classed as a ‘reaction’, or a strong susceptibility to an intolerance of chardonnay, pinot grigio, pinot gris and zinfandel grapes, which adds up. I apparently also have ‘reactions’ to egg white, coffee and yeast, which was a surprise. The next step for me will be removing some of these food groups in isolation to see if I can get the reactions under control – I will drink wine again!” 

Eat yourself well 

Our favourite qualified food specialists on Instagram to brighten up your feed and inspire your cooking.

@movingdietitian 

Paula Norris, dietitian, 87.6k followers 

Aussie Paula offers smart, easy-to-follow tips for improving your diet while busting myths about what’s in your food – and what not to worry about. 

@jshealth 

Jessica Sepel, nutrition expert, 185k followers 

Sepel’s JSHealth plan is focused on finding freedom with food. Jess has a degree in health science and two years of nutritional medicine study. 

@kamillaschaffner

Kamilla Schaffner, nutritionist, 12.2k followers 

An expert in digestive disorders, Kamilla posts daily meal ideas with breakdowns of what every ingredient offers. 

@laurathomasphd

Laura Thomas, nutritionist, 30.3k followers 

Laura incorporates psychology and behavioural science into her work on gut health; her Don’t Salt My Game podcast is a don’t-miss. 

@mikaelareuben

Mikaela Reuben, culinary nutrition consultant, 22.2k followers 

Mikaela’s healthy-eating plan is so popular that her clients include Ben Stiller, Owen Wilson and Whitney Port. 

Images: Unsplash