Anni Summers RD

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Food Intolerances vs Food Allergies

Image depicting Food Intolerances

Food allergies and food intolerances can significantly impact your daily life. Understanding the differences between these conditions, recognising their symptoms, and learning how to manage them can vastly improve your well-being. 

Food allergy or food intolerance?

Food allergies and intolerances are often mistakenly used interchangeably, but they are distinct conditions with different mechanisms. 

  • Food Allergy: If you have a food allergy, this means your immune system is involved, where your body mistakenly identifies a harmless food protein as a threat and produces an immune response. You may experience reactions ranging from mild discomfort to severe allergic responses. Common examples of food allergies include nut, fish or milk protein allergy.  
  • Food Intolerance: By contrast, if you have a food intolerance, this means your body has difficulty digesting certain foods. It typically involves your digestive system and may result from enzyme deficiencies, such as lactose intolerance, or reactions to components of foods or food additives. 

Recognising allergy and intolerance symptoms

Symptoms of food allergies and intolerances and can vary widely and may manifest in different parts of your body.

Food allergy symptoms

  • Not limited to your digestive system. 
  • Include symptoms such as hives, swelling of the lips, tongue, or throat, and skin rashes as well as, in some cases, gastrointestinal issues. 
  • Severe cases can lead to anaphylaxis, a life-threatening condition characterised by difficulty breathing, a sudden drop in blood pressure, and dizziness, requiring immediate medical attention. 
  • Symptoms can occur within minutes to a few hours after eating (IgE-Mediated Allergies) or several hours to days after consuming the allergen (Non-IgE-Mediated Allergies).  

Food intolerance symptoms

  • Symptoms primarily affect your digestive system. 
  • Includes digestive issues like bloating, gas, diarrhoea, abdominal pain, and sometimes constipation. Can also include symptoms such as headaches or migraines. 
  • Symptoms can appear hours or even days after you consume the problematic food. 

Diagnosis of food allergies and intolerances

Diagnosing food allergies

IgE-Mediated (immediate onset) allergies are typically diagnosed using skin prick tests and specific IgE blood tests, which are designed to detect the presence of IgE antibodies for specific allergens. Usually, your GP can arrange testing.  

Non-IgE-Mediated (delayed onset) allergies are more difficult to diagnose due to the delayed nature of the symptoms and the lack of reliable diagnostic tests. Often diagnosed through dietary elimination followed by food challenges, ideally under the supervision of an Allergy Specialist Dietitian. 

Diagnosing food intolerances

Diagnosing food intolerances typically involves a combination of methods due to the varied and delayed nature of symptoms. 

  • Keeping a food diary: Keep a detailed record of everything you eat and any symptoms experienced afterward. This can help pinpoint trigger foods. 
  • Elimination Diet: Temporarily remove potential trigger foods from your diet, then gradually reintroduce them while monitoring for symptoms. 
  • Consultation with a Gastroenterology Specialist Dietitian: A Registered Dietitian experienced in Gastrointestinal Health can provide personalised guidance on creating a balanced diet for food intolerances. 

What about food intolerance testing?

IgG testing for food intolerances is not recommended. While some alternative practitioners advocate for IgG testing, this is not supported by clear scientific evidence. Dietitians and medical practitioners agree that IgG antibodies can signify exposure and tolerance to foods, rather than intolerance. Elevated IgG levels are commonly seen in individuals who frequently eat certain foods without negative effects. Due to insufficient evidence, IgG testing is not advised for diagnosing food allergies or intolerances.  

Misuse of these tests can lead to unnecessary dietary restrictions, nutritional deficiencies, and disordered eating. 

Key takeaways

  • Food allergies and food intolerances can significantly impact quality of life. 
  • Recognising allergy and intolerance symptoms and identifying trigger foods are essential for managing these conditions. 
  • Food allergy tests may be necessary for some types of food allergy.
  • Food intolerance tests are not usually required.
  • IgG food intolerance tests are not backed by clear scientific evidence. 
  • Consultation with a healthcare professional, such as a dietitian, can provide personalised guidance. 
  • Always consult your GP if you think you may have a food allergy. 

Understanding food allergies and food intolerances empowers individuals to make informed dietary choices and lead healthier lives. 

Further reading:

Allergy UK Food Intolerance Factsheet 

BDA Food Allergy and Food Intolerance Factsheet


Meet Anni Summers: Your Gut Health Dietitian for Food and Intolerances

Are you tired of battling with food allergies and intolerances? Look no further! Anni Summers is here to provide you with the essential tools and knowledge to manage your dietary challenges effectively. With years of expertise in this area, Anni is dedicated to guiding you through your journey with food sensitivities, ensuring you feel empowered and in control every step of the way.

How a Dietitian for Food Intolerances Can Support You

Through thorough assessment and analysis, Anni can help identify trigger foods. She offers valuable insights on label reading, meal preparation, and dining out, empowering you to make informed choices and confidently manage your condition.

With Anni’s expertise and compassionate guidance, you can lead a life filled with a diverse range of delicious, allergen-free foods.