Fish Intolerance & Allergy

Fish intolerance can trigger symptoms like bloating, stomach cramps and headaches. Learn more about fish intolerance, fish allergies and the differences between them here.


Fish is amongst the healthiest of foods. It is rich in omega-3 fatty acids, calcium, phosphorus, zinc, magnesium, and other minerals, along with iodine and iron. Health authorities around the world recommend eating fish multiple times a week

Unfortunately, some individuals struggle with fish, experiencing a range of unpleasant symptoms after eating this dietary staple. But it’s not always easy to work out whether it’s the inconvenience of a fish intolerance or the potentially serious health risks posed by an allergy.


The difference between allergies and intolerance

Although the terms allergy and intolerance are often used interchangeably, these are in reality two separate conditions and it’s important not to confuse the two.

Fish Allergy

Allergies involve the immune system. In affected individuals, antibodies respond to foods and other substances as though they were pathogens, triggering reactions that would normally be deployed against infections and disease – and these in turn cause allergic symptoms. For example, someone with a fish allergy might experience:

  • Symptoms of asthma 
  • Skin rashes or hives
  • Sneezing or nasal congestion
  • Headaches
  • Stomach pains and cramps
  • Nausea
  • Diarrhea

Some people may also experience anaphylaxis or anaphylactic shock after eating fish. Typical symptoms include a fall in blood pressure, difficulty breathing, lightheadedness, and swelling of the tongue and throat. This is the most extreme form of allergy and one that can be life-threatening without rapid medical intervention. Anaphylactic reactions to fish are relatively rare when compared to other triggers, but they do occur, so taking precautions is sensible.

Buy Our Food Allergy Test

Discover how your body reacts to a number of food and drink items so you know which ones to avoid.

This blood allergy test measures your IgE antibody levels against 38 key food and drink items including; grains, wheat, nuts, milk, meat, fish, fruit and vegetables.

Fish Intolerance

Allergies are typically lifelong conditions rooted in early childhood exposure to particular environments and foods. Food intolerance, by contrast, is centred in the digestive system. For a variety of reasons, people with one or more intolerances struggle to digest certain foods. This might be because:

  • Their health is poor
  • They’re eating an unhealthy or unbalanced diet
  • Their bodies do not produce certain digestive enzymes in sufficient quantities

Fish intolerance may trigger such reactions as:

  • Bloating
  • Stomach cramps
  • Feeling sick
  • Headaches
  • Rashes

As you can see, many of these overlap with fish allergy symptoms (and indeed, those of other allergies). Typically, however, food intolerances are milder than those of allergies – and with the exception of lactose intolerance, not necessarily permanent. Intolerances can fade if the person affected takes proactive steps to optimise their diet and improve their health.

Buy Our Food Intolerance Test

Discover how your body reacts to a broad range of foods and drinks so you know which ones to avoid.

This comprehensive food intolerance test measures your IgG antibody levels against 134 key foods including; wheat, gluten, dairy, milk, meat, fish, fruits, vegetables, pulses, tea & coffee, herbs & spices, oils and protein supplements.

Taking action

If you regularly feel ill after eating fish, talk to your GP. If they suspect you may have an allergy, they will refer you for specialist testing.

Meanwhile, adjust your shopping habits accordingly. Fish fingers, seafood broth, sushi and haddock fillets are of course all off the menu (at least for now), but do bear in mind that the inclusion of fish in a particular product is not always obvious. Fish extracts can also be found in such products as:

  • Salad dressing
  • Taramasalata and similar spreads
  • Some sauces – for example, Worcestershire sauce
  • Asian foods prepared with fish-based sauces, as well as fried rice and spring rolls

People who are very sensitive to their allergic triggers may experience severe symptoms when exposed to even small quantities in processed food products. So you will need to acquire the habit of reading food labels carefully.

But what if the allergy tests are negative but you still experience unpleasant bouts of indigestion after eating fish? Then the chances are good that you have developed an intolerance. But how do you find out for sure?

Order your test

We believe that in providing you with your test results and relevant information in each section, your results can form the beginning of a journey, enabling you to make positive changes to your daily diet and environment.

A food intolerance home testing kit is one avenue worth exploring. Take a painless finger-prick blood sample and you will receive a detailed analysis, indicating the responses made by an antibody called IgG to multiple food substances: including fish. The digestive problems caused by a food intolerance can cause food particle build-up, damaging the inner lining of your gut and triggering IgG antibodies.

Whether you need to avoid fish permanently or just for a while, think about the nutrients it supplies so well. Rearrange your diet so that your body will receive a rich supply of protein, minerals, omega-3s and iron from other sources. You may end up feeling better than you have in years.

Complementary Alternative Medicine (CAMS)

Our food sensitivity tests are carried out using bioresonance therapy and is categorised under Complementary and Alternative Medicines (CAMs) which covers a wide range of therapies that fall outside mainstream medicine. Tests and related information provided do not make a medical diagnosis nor is it intended to be a substitute for professional medical advice, diagnosis or treatment.

Always seek the advice of your doctor or other qualified health provider if you have a medical condition or with any questions you may have regarding a medical condition and/or medical symptoms.

Order your test

We believe that in providing you with your test results and relevant information in each section, your results can form the beginning of a journey, enabling you to make positive changes to your daily diet and environment.