The Top Five Symptoms of Food Intolerances

Top five food intolerance symptoms

Up to 20% of the world’s people suffer from food intolerances today, which is huge! Food intolerances cause many and varied symptoms and have the ability to affect all body systems. However, there are a number of more common symptoms to look out for, and we are going to cover those today. If you feel food intolerances are an issue for you, definitely keep reading to learn what to watch for.

What are Food Intolerances?

This has been covered in detail in previous posts, but we need a quick recap here to put things into context for you.

Food intolerances are a bodily reaction, usually digestive in nature, that occurs when a particular food is consumed. The digestive tract reacts to protein components and sometimes other compounds found in the food, and this produces a reaction that doesn’t occur in the rest of the population. These reactions take between 2 and 72 hours to surface, and because of the delay, it can be difficult to tell what foods the body is reacting to.

Food allergies, in contrast, are an immune system reaction, that occurs immediately. They can result in anaphylaxis, which we know is life-threatening by its very nature.

Our bio-resonance hair intolerance test is an amazing tool if you suspect food intolerances, but aren’t sure which foods are the culprits. It will give you a list of foods to avoid, removing any doubt or hard work. 

Bowel irregularities, namely Diarrhoea or constipation

Issues with bowel irregularity are one of the top symptoms of food intolerance. The main reason for this is that food intolerances are digestive in nature, and most often a result of some upset or dysfunction in that system. Reduced stomach acidity, a lack of certain enzymes, bacterial overgrowth and other digestive concerns can all contribute to the development of food intolerances.

If we then consume our intolerance foods, we effectively introduce a big load of inflammation into the digestive tract. This is what can cause issues with bowel irregularity, alongside bacterial imbalances.

The following foods are known to cause constipation:
  • Refined carbohydrates – white bread, pasta, crackers etc
  • Gluten-containing foods
  • Processed foods and those high in refined sugar

These foods are known to cause diarrhoea

  • Dairy products
  • Foods high in fructose such as garlic, onion, pear and apple
  • Coffee
  • Spices
  • Foods high in refined sugars or artificial sweeteners that are consumed to excess


Another classic food intolerance symptom! Bloating is essentially an excess of gas in the digestive system, which causes the classic abdominal distention, gas, wind and pains that come along with the bloat.

Most often there is a bacterial imbalance that causes the bloating, particularly in conditions such as SIBO, or where antibiotics have been taken recently. Bloating is a very common symptom of lactose intolerance, but certainly not singular to that. We have a FAQ all about lactose intolerance if you’d like to read further on that.

Eczema and skin issues

Eczema has been linked to the health of the digestive microbiome quite extensively, and we also know that overall skin health is profoundly connected to digestive health.

Aside from any apparent digestive disease states or issues, when we eat foods that our bodies are intolerant to it causes a lot of inflammation to occur. This inflammation damages our digestive microbiome, sometimes quite extensively, and can also result in SIBO, leaky gut and other issues developing. Eczema and other skin rashes can then develop outwardly on the skin as a result of what is going on internally. This includes adult acne too.

A Naturopath is best placed to help you heal your skin from the inside out, while also aiding your body to recover from food intolerances.

Reflux/ GORD

This is another massive symptom for food intolerance sufferers. In 2017 a study was undertaken, and the results showed that 91% of the test subjects suffered up to 5 different food intolerances alongside their reflux. These food intolerances were the cause of their symptoms, and milk was the highest percentage intolerance. The study also showed that removing the food intolerance foods significantly reduced the reflux symptoms.

Dairy has a strong link to reflux, but it is by no means the only food that causes it.

Migraines and headaches

Having a persistent headache or regular migraines can be debilitating. It’s also a sign that you may be plagued with undiagnosed food intolerances. If any of the above symptoms tick the boxes for you, and you also suffer persistent migraines or headaches, it is well worth you having a food intolerance test done. Due to the nature of headaches and migraines, it can be challenging to pinpoint what the cause is. Our bio-resonance hair intolerance test can give you a list of foods that your body is intolerant to, therefore taking the guesswork out of the equation. Find out more HERE!

In regards to Migraines, foods that are high in amines are known culprits. Foods on this list include


  • Cacao/cocoa – ie.Chocolate
  • Wine, particularly red
  • Cheese
  • Coffee or caffeine in general
  • MSG

Our article ‘Are food intolerances causing your migraines?’ goes into more detail about food intolerances and their links with Migraines and headaches. Head on over there if this is of interest to you.


We’ve covered off the 5 most prevalent symptoms that someone with food intolerances suffers with. They are most commonly digestive in nature, but food intolerances have the power to affect every system in the body, including the skin and nervous systems. The top 5 symptoms are:
  1. Bowel irregularities – diarrhoea/constipation
  2. Bloating
  3. Eczema and other skin issues
  4. Reflux or GORD
  5. Migraines/ Headaches