Food intolerances
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Symptoms of a food intolerance
If you have a food intolerance, symptoms usually appear a few hours after eating the food or ingredient you're intolerant to.
Common symptoms can include:
You may also experience other symptoms like:
- Headaches
- Feeling tired or exhausted
- Feeling sick
- Constipation
- Joint pain
- Skin rashes
Symptoms can last anywhere from a few hours to a couple of days.
Food allergies typically cause symptoms like:
- Itchy skin
- Wheezing
- Swelling of the lips, face and eyes
If you notice symptoms of a serious allergic reaction, make sure to act immediately.
Call 999 if:
- Sudden swelling of lips, mouth, throat, or tongue
- Rapid breathing, wheezing, or difficulty breathing
- Tight throat or trouble swallowing
- Skin, tongue, or lips turning blue, grey, or pale (more noticeable on palms or soles for darker skin)
- Confusion, drowsiness, or dizziness
- Fainting or being unresponsive
- A limp, floppy, or unresponsive child (head may fall to the side or difficulty focusing)
These symptoms could indicate a serious allergic reaction (also called anaphylaxis) and require immediate medical attention. Emergency teams are trained to help and provide the necessary treatment.
Food intolerances, on the other hand, don’t involve the immune system and don’t carry the risk of severe allergic reactions like anaphylaxis.
If you or your child notice symptoms of food intolerance that keep coming back, it’s important to speak to your GP for advice.
They can help identify what’s causing the symptoms and suggest ways to manage them.
What causes a food intolerance?
Food intolerances happen when your body struggles to digest certain foods. This can be due to how your digestive system processes specific components in food. Unlike food allergies, which involve an immune system reaction, food intolerances don’t trigger a severe allergic response like anaphylaxis, but they can still cause unpleasant and uncomfortable symptoms. If you notice symptoms recurring after eating certain foods, it’s important to speak to your GP. Identifying the exact trigger can help you take control and make a big difference in how you feel. Food intolerances can affect people in different ways, so getting advice is important to help manage your symptoms.
Common causes of food intolerances
The most common food intolerance is lactose intolerance, where your body can’t digest lactose, a natural sugar found in milk and dairy products like cheese and yoghurt. Lactose can also be found in processed foods like cereals, biscuits and protein shakes.
Other types of food intolerances include:
- Gluten intolerance (wheat, rye, barley) – in bread, pasta, cereals
- Histamine intolerance – present in wine, cheese, fermented foods
- Caffeine intolerance – found in coffee, tea and some fizzy drinks
- Alcohol intolerance – certain alcoholic drinks may trigger symptoms in some people
- Sulphite intolerance – found in drinks like cider, beer and wine
- Salicylate intolerance – naturally found in some fruits, vegetables, herbs and spices
- Monosodium glutamate (MSG) intolerance – found in ripened fruits, cured meats, savoury foods
Diagnosing & testing
If you suspect that you or your child may have a food intolerance, it’s important to get professional guidance. A GP may refer you to a food and nutrition specialist, like a registered dietitian, to help identify and manage your symptoms.
While food intolerances can be frustrating, the good news is that understanding your triggers can make a real difference. Your GP may recommend the following steps to help pinpoint a food intolerance:
- Elimination diet – Cut out foods, then reintroduce to spot triggers
- Breath test – Often used for suspected lactose intolerance
- Food & symptoms diary – Track meals and symptoms to identify patterns
- Blood tests –To measure antibodies in the blood to pinpoint foods that may cause delayed reactions
Some home testing kits for food intolerances might offer an indication of potential triggers, but it’s important to approach these results with caution.
These tests can’t diagnose food intolerances, so they could lead to unnecessary food restrictions, which might result in an unbalanced diet.
If you’re considering using a home test such as the MyHealthChecked intolerances and sensitivities or the YorkTest food intolerance and allergy test, it’s important to share the results with your GP or a dietitian before making any changes to your diet, like starting an elimination plan.
Your GP can help you interpret the findings and create a plan to manage your symptoms effectively.
Common intolerances
Here’s a closer look at some of the most common types of food intolerances, their symptoms and how they are managed.
Histamine is a naturally occurring chemical found in certain foods like wine and cheese. While most people can tolerate normal amounts, some may experience symptoms due to a reduced ability to break histamine down. Histamine intolerance is thought to be due to the lack of an enzyme called diamine oxidase.
Symptoms can include:
Symptoms typically happen 30 minutes or more after eating and vary from person to person. If you think you have histamine intolerance, under the guidance of your GP, try avoiding high-histamine foods for 2-4 weeks while keeping a food and symptoms diary. Gradually reintroduce these foods to determine your tolerance.
There are no reliable tests for histamine intolerance, so it’s important to rule out true food intolerances with a healthcare professional first.
Lactose intolerance occurs when the body doesn’t produce enough lactase. The enzyme is needed to digest lactose, the sugar found in milk, dairy products, and often in processed foods such as cereals, biscuits, and protein shakes.
Symptoms can include:
- Diarrhoea
- Bloating
- Passing wind
- Abdominal pain or discomfort
- Occasionally, constipation or nausea
Following a low-lactose diet can help manage symptoms, but many people can tolerate small amounts of lactose. For help on how to adjust your diet, speak to a dietitian who can provide tailored advice.
It’s important to note that goat, sheep and other animal milk also contain lactose, so they aren’t suitable substitutes for managing lactose intolerance.
Gluten intolerance, or non-coeliac gluten sensitivity, is not well understood and remains controversial. It may involve the immune system or be linked to other components in wheat, like fructans, a type of fermentable carbohydrate.
Symptoms can include:
- Abdominal pain, bloating, altered bowel habits, nausea and reflux
- Fatigue, headaches, joint pain, anxious feelings, feeling low and ‘brain fog’
Gluten intolerance is diagnosed by excluding other reasons like coeliac disease and wheat allergy. A trial elimination of wheat, followed by reintroduction, can help confirm whether gluten is a trigger.
Working with a dietitian is important to avoid unnecessary dietary restrictions and help ensure a balanced diet.
Treating & living with a food intolerance
If you’re living with a food intolerance or food sensitivity, avoiding or reducing the foods or ingredients that trigger your symptoms can make a big difference. Before making any changes to you or your child’s diet, it’s important to speak to a GP or dietitian. Cutting out certain foods without professional advice might mean missing out on important vitamins and minerals, especially for growing children. With guidance, you can manage your symptoms and enjoy a balanced, nutritious diet that works for you or your family.
Living with a food intolerance
Managing a food intolerance might feel overwhelming at first, but with the right approach, it’s something you can take in your stride. Simple adjustments and support can help you enjoy life while keeping symptoms under control.
It’s important to involve your GP or dietitian, especially in children before cutting out foods. Some foods, like cow’s milk, are important for healthy growth, providing calcium, vitamin D and protein. A healthcare professional can help you find alternatives that fit your needs.
Dining out or attending social events with a food intolerance doesn’t have to be stressful. You can try these tips:
- Let restaurants or hosts know about your needs ahead of time – they’ll often be happy to accommodate
- Choose simpler dishes to avoid hidden ingredients
- Keep snacks or suitable alternatives on hand, just in case
Reading food labels is a great way to ensure you’re avoiding trigger foods, even when they might be listed under different names. There are plenty of resources, including apps or fact sheets like Yuka and Open Food Facts, to help make it easier.
If your food intolerance involves something like lactose, digestive aids like lactase enzymes can help you enjoy certain foods in moderation. You can ask your GP or pharmacist about options that might work for you.
Sometimes food intolerances can feel tricky to manage, especially if symptoms persist or don’t improve with an elimination diet. If that happens, or if your child has symptoms like tummy pain, diarrhoea or struggles with growth, it’s important to reach out to your GP or dietitian. They may recommend further tests or specialist support to help get things back on track.
A food intolerance doesn’t have to hold you back. With a bit of planning, you can continue to enjoy your favourite meals, social occasions and daily life with confidence. If you’re ever unsure about how to manage your symptoms, speak to your GP or dietitian.
Having anxious feelings about dietary requirements is completely normal, especially if you’re managing a food intolerance. Worries about eating out, trying new foods or explaining your needs to others can feel overwhelming at times. But with the right mindset and strategies, you can take control and feel more confident in managing these situations.
Having dietary requirements often means being extra careful about what you eat, and it’s natural to feel uneasy about the potential for mistakes. It’s important to find ways to manage those anxious feelings so they don’t take over your daily life.
Tips for managing anxious feelings around food
Be prepared
Feeling prepared can ease worries. Check menus beforehand, pack safe snacks, and inform friends or restaurants in advance.
Practise conversations
It's natural to feel nervous about discussing your dietary needs, but it gets easier with practice. Try rehearsing a clear and polite explanation.
Stay informed
Understanding your dietary requirements can reduce your fear of the unknown. If unsure about a food, ask questions or check labels.
With experience, managing dietary requirements becomes easier, and confidence grows with practice.
Living with dietary requirements can be challenging, but with time, support, and strategies, you can enjoy meals and social situations confidently.
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Frequently asked questions
There isn’t a definitive top 3, but lactose intolerance, gluten intolerance and histamine intolerance are among the most common.
- Lactose intolerance – where the body struggles to digest lactose, a sugar found in milk, dairy products and other foods
- Gluten intolerance – a reaction to gluten found in foods like bread, pasta and cereals
- Histamine intolerance – sensitivity to histamine in foods like wine, cheese and fermented products
If you think you have a food intolerance, it’s important to speak with your GP to help explore your symptoms and get advice.
Food intolerance is usually managed by avoiding or reducing the food-causing symptoms. An elimination diet may help identify triggers, but it’s important to only do this with guidance from a GP or dietitian to avoid missing out on vital nutrients. If you're unsure or have ongoing symptoms, make sure to speak with your GP for advice on how to manage your diet.
Developing intolerances to multiple foods can happen due to changes in your body, like changes in your digestive system, gut health or enzyme production. Factors like stress, infections or certain medical conditions can also play a role. If you're experiencing this, it's important to speak to your GP. They can help identify any underlying issues and guide you in managing your symptoms.
If you feel like you're intolerant to many foods, it's important to speak to your GP. They can assess your symptoms and may refer you to a registered dietitian for advice and support. A specialist can help you identify foods you can eat, create a balanced meal plan and make sure that you're getting the nutrients you need. You should avoid making significant dietary changes without professional guidance to prevent you from missing out on essential nutrients.
Knowing what food intolerance you have can take time and patience. A GP or dietitian may recommend keeping a food and symptoms diary, noting what you eat and any reactions you have. This can help highlight patterns and potential triggers.
In some cases, you may be advised to try an elimination diet, where you remove a suspected food from your meals for a set time to see if symptoms improve. After this, the food is gradually reintroduced to confirm if it’s the cause.
It’s important not to self-diagnose or make significant dietary changes without professional advice. Make sure to speak to your GP or dietitian for guidance on safely managing and identifying food intolerances.
If you ignore lactose intolerance and continue eating dairy, you may experience uncomfortable symptoms like bloating, stomach pain, diarrhoea or nausea. While these symptoms aren’t typically dangerous, repeated irritation can affect your digestive system and overall wellbeing.
In rare cases, ignoring lactose intolerance may lead to long-term issues, like nutrient deficiencies if you avoid dairy without replacing key nutrients like calcium and vitamin D.
If you think you’re lactose intolerant, it’s important to speak to your GP or a dietitian. They can help you manage your symptoms and help make sure that you’re meeting your nutritional needs while avoiding triggers.
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