6 Signs You Might Have A Food Intolerance

6 signs you might have a food intolerance

Guest writer, nutritionist Sarah Flower, looks at the difference between food allergies and intolerances, and pinpoints the six most common signs of food intolerance.

Do you have a food intolerance?

When we're suffering from a range of health issues, it’s human nature to try and find a direct cause. We have all heard the phrase ‘we are what we eat’, but how much does our food affect our health? Food intolerances affect 45% of the population and the symptoms of a food intolerance can be varied.

As a nutritionist, I often see clients with a range of symptoms where doctors have not been able to resolve fully. Food intolerance testing can be a very useful tool, alongside repairing the gut, lifestyle and diet changes.

Food Intolerance vs Allergy

Food intolerances are very different to food allergies. An allergic reaction can happen within two hours of being exposed to the food, in some cases can be within minutes of exposure. Only around 2% of the UK population have a genuine food allergy and these tend to stay for life. Allergies raise IgE antibodies and can affect our airways, skin and digestive system and can, in some cases, be fatal.

Food intolerances on the other hand can take up to 72 hours to show a reaction, and these reactions, caused by raised IgG antibodies (Immunoglobulin Gs), can be much more subtle and are never fatal. Over time, a raised IgG can cause more inflammation and irritation, especially on the digestive tract. This can cause a wide range of symptoms as our digestive tract is not only there to deal with your food, but over 80% of the immune system comes from our gut. Anything that upsets this complicated and integrated structure will have a knock-on effect on our overall health.

Food intolerances can be very hard to identify through elimination diets alone. It's also worth noting that it can take up to 8 weeks for the body to stop reacting to the antibodies, so if you are trying to avoid foods, you need to ensure you remove all traces for at least 8 weeks.  

A food intolerance test will not identify the following: 

Lactose Intolerance: despite the name, you are not intolerant to lactose, you are actually deficient of an enzyme called lactase, which helps break down and digest lactose. Your GP can test for this using a breath test.

Coeliac Disease: Coeliac disease is when gluten causes damage to the digestive tract. If you are intolerant of wheat or gluten, it doesn't damage the digestive tract, but instead can cause an antibody reaction.

Symptoms of a Food Intolerance

Food intolerances can cause a range of symptoms. The type of things we all tend to ‘put up with’ or make excuses for: "I’m tired because I've done too much!", "I’ve keep getting sinusitis, so I have a low immune system", or "I have eczema, is it my washing power?"

How many of us link these symptoms with food?

1. Mental Health

Mood Changes, including depression, anxiety, stress is quite common in today’s world, but they could all link back to diet and possible food intolerance.  We know that gut health has a direct impact on our mental health and vice versa. A food intolerance not only causes inflammation in the gut but also upsets the microbiome, leading to more health problems. Identifying trigger foods alongside restoring good gut health is key to our mental health.  

2. Pain

Headaches, migraines, joint pain, fibromyalgia can be so debilitating. A food intolerance can lead to inflammation in the joints, causing you to have more aches and pains, leading to tense muscles and therefore more pain. Food intolerances can also affect our gut and liver, which can also contribute to migraines and headaches. The University of York conducted a survey to understand the benefits of elimination diets based on the results of a food intolerance test.

Out of 259 people who reported experiencing migraines, 76 per cent reported an improvement having removed their ‘trigger’ foods.  Removing trigger foods can help settle the inflammation, whilst implementing dietary and lifestyle changes. For example, a high carb/sugar diet is very inflammatory as it the use of man-made oils and transfats, increased stress and poor sleep.

3. Skin Problems

Hives, rashes, itchy skin, eczema and even psoriasis can be caused by a food intolerance, and a compromised immune system. Despite overwhelming and compelling evidence of an association between skin problems and diet, very few sufferers are tested for food intolerance, yet I regularly see an established link with many foods, especially things like dairy, wheat and eggs for common conditions such as eczema. As part of my clinic work, I also look at restoring gut health, which in turn boosts the immune system.

4. Fatigue and low energy

We all make excuses when we experience low energy or fatigue, but these symptoms really do need to be checked. Once it has been established there is no medical reason for the energy levels and things like Iron and B12 levels have been checked, we need to explore the food connection. According to Lorisan Laboratories, 1 in 5 people tested for food intolerance last year listed tiredness as one of their symptoms.

5. Respiratory Problems

You may not associate blocked sinuses, asthma or other respiratory problems with food intolerance, but once again we go back to the inflammatory response on the gut, the lowering of the immune system, and then being more susceptible to ill-health, especially in our weakest ‘problem’ areas. We also know respiratory conditions such as asthma can be made worse with dairy (very mucus-forming) and can also be improved by removal of gluten.

However, don’t assume wheat or dairy are always the trigger foods for respiratory problems: eggs, yeast, soya or other foods can also be problematic.

6. Gut Issues

Good gut health is key to good overall health, especially when it comes to our immune system. Our diets have changed dramatically over the last 40 years, with much more processed foods and poor dietary habits. Problems such as IBS, acid reflux, bloating, etc., all need to be explored thoroughly and food intolerance tests need to be part of that exploration processes. Food intolerances can cause inflammation in the gut, triggering a variety of symptoms, and intolerance testing helps to identify any trigger foods whilst we repair, strengthen and restore good gut health.


SArah Flower NutritionistSarah Flower is a leading UK Nutritionist and Author. For more information on her work visit www.sarahflower.co.uk.


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