FODMAPs sensitivity vs food intolerance - what's the difference?

Similar symptoms, problem foods, and elimination processes. It’s confusing right?!

Foods cause tummy troubles and other symptoms for many reasons. Conditions that cause reactions in susceptible people include FODMAPs sensitivity, food chemical intolerance, allergy and coeliac disease.

FODMAPs sensitivity and food chemical intolerance have a few things in common. So, we often look at them both when working out triggers for certain people.

Understanding the difference between the two is important because the underlying cause and approach to dealing with them are different.

So what are they?

Unlike allergies and coeliac disease, intolerances and FODMAPs sensitivity do not involve the immune system.

Rather, food chemical intolerance is triggered by – you guessed it – food chemicals! These chemicals cause symptoms by irritating nerve endings in the body of sensitive people. 

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Most people think of food chemicals as artificial. Yet many different foods contain natural food chemicals. They include vitamins we need for health and the flavour that makes food so delicious. Salicylates, amines and glutamate are examples of natural chemicals that are likely to upset sensitive individuals.

Different foods can have the same type of chemical, and one food can contain several types of chemicals. People can be born sensitive, or environmental triggers, a dietary change or a viral infection can cause symptoms at any age.

FODMAPs stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are types of carbohydrates that our bodies don’t absorb well. As a result, your large intestine breaks them down.

In most people, this isn’t a problem. But in sensitive people, this can cause a reaction. FODMAPs are found in a range of foods. Confusingly, many high FODMAP foods are also high in food chemicals. Like food chemicals, the same type of FODMAP can be found in different foods, and one food can contain many types of FODMAP.

Symptoms

Symptoms for both conditions vary from person to person.

FODMAPs sensitivity hosts a range of possible symptoms. These include bloating, diarrhoea, flatulence, abdominal pain, constipation or diarrhoea.

Confusingly, food chemical intolerance may show itself via all of the above too. The difference is that food intolerance often comes with a host of other symptoms. In addition, it might cause hives, headaches, sinus issues, mouth ulcers, nausea, skin rashes and mood changes.

Many of us might eat more healthy high chemical foods or FODMAP containing foods in an attempt to feel better, but unfortunately, this may only aggravate symptoms.

Diagnosis

Because the immune system is not involved in either condition, diagnosis is tricky. Elimination diets with structured challenges are the only way to determine both FODMAP and food chemical triggers.

Diagnosis of either condition doesn’t just involve determining whether you are sensitive to food chemicals or FODMAPs as a whole. It aims to find which chemicals or FODMAPs are triggers for you, and how much you can tolerate without symptoms.

To find out if FODMAPs are the cause, health professionals may use the low FODMAP diet. While for food chemical intolerance, they might use the elimination diet. These follow a similar process. They include an elimination phase, challenge phase and reintroduction phase.

Elimination: Elimination takes 2-6 weeks, depending on how long it takes symptoms to subside. Elimination means reducing the intake of groups of foods that contain moderate-high levels of FODMAPs or food chemicals.

Challenges: These foods are re-introduced in a specific order. This allows us to find out which ones are causing the symptoms.

Re-introduction: The amount that causes symptoms can then be examined and dietary habits can normalise.

How much is too much?

Both FODMAP intolerance and food chemical intolerance work via a dose-response relationship. A person with an intolerance may not be symptomatic until they reach a certain threshold. This means you can eat some of the given problem food safely, with no symptoms.

People with food chemical intolerance might see some symptoms improvement following a low FODMAP diet. This effect might diminish over time. Persistent unexplained symptoms or reactions to low FODMAP foods might indicate that a food chemical intolerance exists.

A final note 

There’s no doubt about it. Both the low FODMAPs diet and elimination diet for food chemical intolerance can be challenging. Therefore, it is important to implement either of these with a dietitian experienced in FODMAPs and food chemical intolerance.

Need help with the low FODMAP diet? Our FREE dietitian developed program will guide you through it, step-by-step. Includes a low FODMAP food guide. Sign up now.

If you are experiencing gut symptoms and have not been recommended a low FODMAP diet by a health professional, get started with the manage your gut symptoms program.

Reviewed by the healthylife Advisory Board May 2022