Parent, activist and allergy author Alexa Baracaia addresses this vital question with a combination of science and personal experience. It’s an essential read for worried parents.
When our son was diagnosed with multiple food allergies at just six months old, we were thrust into a bewildering new world.
Suddenly, what might seem simple to the outsider – you’re either allergic to something or you’re not, right? Just avoid it – became fraught with endless (in some cases unanswerable) questions. What caused it? How do we manage it? What will happen in the future?
One thing I realised early on is that getting a handle on the basics is a huge help in navigating the bumpy path ahead. The most important tool in your allergy management toolkit – medication aside – is knowledge.
It doesn’t get much more fundamental than the difference between an intolerance and an allergy. Two terms often mistakenly used interchangeably, both are defined by adverse reactions to foods under the blanket label of ‘food hypersensitivity’. So what’s the difference, and why does it matter?
Confusing the two conditions can result in risky behaviour if you have a serious allergy, or overly strict avoidance if you have an intolerance.
Firstly, the mechanisms behind them: where a food allergy involves the immune system, an intolerance does not. And where a food allergy can sometimes lead to severe symptoms, including life-threatening anaphylaxis, an intolerance will not.
This is not to downplay the significance of food intolerances, which can be both debilitating and troublesome to diagnose. But the distinction is important. In general terms, people with an intolerance may be able to eat small amounts of the food to which they are intolerant. Those with food allergy, by contrast, usually react to very small doses, which can trigger quick and severe reactions.
Confusing the two conditions can result in risky behaviour if you have a serious allergy, or overly strict avoidance if you have an intolerance.
Here’s the lowdown on both:
Food Intolerance
As mentioned, unlike a food allergy, an intolerance does not involve the immune system.
Symptoms can vary greatly and typically occur slowly (hours or even days) after eating significant amounts of a particular food, and usually because the body has trouble processing that food effectively.
Although these symptoms are not as potentially dangerous as food allergy reactions, they can still be distressing. They include bloating, diarrhoea, nausea, vomiting, fatigue, eczema and even joint pain.
Many food intolerances involve the digestive system – such as lactose intolerance, where the body cannot produce enough of the enzyme needed to digest lactose, a sugar found in cow’s milk. Wheat is another common culprit, and food intolerance may also be linked to conditions such as irritable bowel syndrome (IBS).
According to the British Society of Allergy and Clinical Immunology (BSACI), some 20 per cent of people believe they have an intolerance, and have changed their diet as a result, but in reality the percentage is likely to be much lower.
Because symptoms are so varied, and occur a while after consuming the food, an intolerance can take time to pinpoint. Unfortunately, there is no diagnostic test (the only exception being if lactose intolerance is suspected). This is worth keeping in mind as there are, frankly, too many private testing firms out there claiming otherwise.
If you suspect a food intolerance, seek the advice of your GP. Once diagnosed, the only current treatment is avoidance of the known food trigger(s). It is important to do this under proper medical guidance, as cutting whole food groups out of the diet can result in poor nutrition.
Food Allergy
Our immune system protects us from invading organisms that cause illness. If you have an allergy, your immune system mistakes an otherwise harmless substance as an invader. This substance, usually a specific protein within a food, is called an ‘allergen’.
What most of us understand as food allergy is more technically known as IgE-mediated food allergy, in which the immune system overreacts to the allergens by producing Immunoglobulin E (IgE) antibodies. These travel to cells that release histamine and other chemicals, causing an allergic reaction.
Symptoms of food allergy usually occur fairly quickly, within 30 minutes of eating, and may involve tingling or itching in the lips, tongue, mouth or throat. There may be runny or itchy eyes and sneezing, as well as abdominal pain, nausea or vomiting, swelling of the lips, face or eyes (‘angioedema’) and sometimes a nettle-like rash known as hives or urticaria. Other rare and more serious symptoms include swelling of the throat, difficulty breathing, wheezing, chest tightness or breathlessness – known as anaphylaxis or an anaphylactic reaction.
Did you know?
The word ‘allergy’ is derived from the Greek ‘allos’, meaning different or strange, and ‘ergon’, meaning activity.
Symptoms of food allergy usually occur fairly quickly, within 30 minutes of eating, and may involve tingling or itching in the lips, tongue, mouth or throat.
While an allergy specialist will run skin prick tests and/or blood tests to measure the likelihood of an IgE-mediated food allergy, in isolation these tests cannot conclusively diagnose or rule out allergy. An allergist will also take a thorough history of the patient, including past reactions and symptoms, and may even run a supervised in-hospital food challenge if results are in doubt.
In terms of prevalence, it’s estimated that between six to eight per cent of children and up to four per cent of adults have a food allergy, with the most common including milk, egg, peanuts and tree nuts, seeds (usually sesame) and fish.
You may have heard of the ‘top 14’ allergens, which, under UK and EU law, a food business must highlight if used as ingredients. But this list is by no means exhaustive and there are many other allergens outside the top 14 – making avoidance of these often quite difficult. Public awareness of these is also sketchy, causing issues when shopping or catering for someone with non-top 14 allergies.
We’ve faced that hurdle ourselves, with our son developing allergies when younger to legumes – chickpeas, peas and lentils – as well as, in infancy, banana. (Turns out, when you have a baby with banana allergy, there’s a toddler wielding one around almost every corner.)
Just to muddy the waters a little more – that’s the thing about allergies: they’re complicated! – there is another type of food allergy that also involves the immune system (hence why it’s an allergy and not an intolerance) but which isn’t caused by IgE antibodies. This is known as non-Ige mediated food allergy.
These reactions are caused by other cells in the immune system and can take several hours to develop. This type of allergy is harder to diagnose, with symptoms such as eczema, diarrhoea, constipation and, in more severe cases, growth problems occurring over a longer period.
People can have either IgE-mediated or non-IgE mediated food allergies and some may even have symptoms from both. Allergies also present differently in different people and at different times, so reactions will not always be the same.
And, just to top it all off, some symptoms that look like allergy – for instance hives or swelling – may be caused by something else entirely, such as a virus or bacterial infection.
That’s why a proper diagnosis by an allergy specialist is so important. Find one in your local area by heading to the BSACI’s ‘find a clinic’ tool at bsaci.org/find-a-clinic.
Did you know?
The word ‘allergy’ is derived from the Greek ‘allos’, meaning different or strange, and ‘ergon’, meaning activity.
The ‘top’ 14 food allergens
In the UK and EU, food law defines the following 14 allergens as the most prevalent and potent:
- Celery
- Cereals containing gluten (e.g. wheat, rye, barley and oats)
- Crustaceans (e.g. prawns, crabs and lobsters)
- Eggs
- Fish
- Lupin
- Milk
- Molluscs (such as mussels and oysters)
- Mustard
- Peanuts
- Sesame
- Soybeans
- Sulphur dioxide and sulphites
- Tree nuts (such as almonds, hazelnuts, walnuts, brazil nuts, cashews, pecans, pistachios and macadamia nuts)
Food businesses must inform you if any of these allergens are used as ingredients in the food and drink they provide.
Alexa Baracaia
Alexa is a journalist, author and parent to a fully paid-up EpiPen-toting teen.
A former full-time newspaper arts correspondent and section editor, she now freelances for a number of online and print publications.
Following her son’s diagnosis as a baby she took to Twitter in search of other families in the same boat. There, she founded the popular forum #allergyhour, which ran for ten years. A vocal allergy advocate, she has helped lead campaigns to counter blanket ‘may contain’ labelling, advised chains including Leon and co-ordinated a 150-strong group response to the government’s allergen labelling consultation. She believes clear communication from all sides is key when it comes to living with allergies.
A long-standing judge for the Free From Food Awards, Alexa was named their Free From Hero for 2022.
Her debut book, ‘My Family and Food Allergies: The All You Need to Know Guide’, was published by Sheldon Press in 2021.
She lives in Hackney, London, with her husband, two children and a lot of Lego.
My Family and Food Allergies: The All You Need to Know Guide by Alexa Baracaia is out now, published by Sheldon Press and available in both Kindle and print formats.
