Food Intolerance

Food intolerance happens when your body finds it hard to digest certain foods. It's different from a food allergy and usually isn't dangerous, but it can make you feel quite unwell.

What are the symptoms?

If you have a food intolerance, you'll usually notice symptoms a few hours after eating the problem food. The most common signs are:

• Diarrhoea
• Feeling bloated
• Wind (farting more than usual)
• Tummy pain

You might also get other symptoms like:

• Headaches
• Feeling very tired
• Feeling sick
• Constipation
• Joint pain
• Skin rashes

These symptoms can last anywhere from a few hours to several days.

How is food intolerance different from food allergy?

This is really important to understand. Food intolerance is not the same as food allergy:

• Food intolerance makes you feel unwell but isn't usually dangerous
• Food allergy can cause serious reactions like itchy skin, wheezing, or swelling of your lips, face and eyes

When should you get emergency help?

Call 999 immediately if you or someone else has:

• Sudden swelling of lips, mouth, throat or tongue
• Very fast breathing or struggling to breathe
• Tight throat or trouble swallowing
• Skin, tongue or lips turning blue, grey or pale
• Suddenly becoming very confused, drowsy or dizzy
• Fainting and can't be woken up
• A child becoming limp, floppy or not responding normally

These could be signs of a serious allergic reaction that needs immediate hospital treatment.

What causes food intolerance?

Food intolerance happens when your body can't properly digest certain foods or ingredients. The most common type is lactose intolerance - when your body struggles to digest lactose (a sugar found in milk and dairy products like cheese and yogurt).

You can be intolerant to many different foods and ingredients, including:

• Gluten (found in wheat, rye and barley - so in bread and pasta)
• Histamine (found in wine and cheese)
• Caffeine (in coffee, tea and some fizzy drinks)
• Alcohol
• Sulphites (in cider, beer and wine)
• MSG (found in some savoury foods)

Getting help and testing

Speak to your GP if you or your child keeps getting symptoms that might be food intolerance.

Your GP might refer you to a food and nutrition specialist (called a dietitian). They might suggest:

• A special diet where you avoid suspected foods for a few weeks, then slowly add them back
• Blood tests
• A breath test (especially for lactose intolerance)
• Keeping a food and symptoms diary

Important warning: Don't buy home testing kits that claim to diagnose food intolerances. These often aren't accurate and might tell you to avoid lots of foods unnecessarily, which could be harmful.

Managing food intolerance

If tests confirm you have a food intolerance, you'll usually need to avoid or reduce the problem foods. However, never cut foods from yours or your child's diet without speaking to your GP or dietitian first. This is especially important for children, as removing foods could mean missing out on important vitamins and minerals needed for healthy growth.

Remember, food intolerance is manageable with the right guidance and support from healthcare professionals.

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Based on NHS.uk guidance. Written by Dr Krishnan Pasupathi, NHS GP.