Does something in your diet disagree with you? Here’s how to tell if you have a food intolerance
It may seem that everyone has an intolerance to some type of food. But how do you actually know if you have a food intolerance?
First of all, let’s talk about what a food intolerance actually is. Food intolerances affect up to 20% of the adult population. Although they are not life-threatening, they can cause unpleasant symptoms, which can have a big impact on a person’s quality of life. Some of the most common symptoms include bloating, cramps and diarrhoea. As well as other symptoms such as headaches.
It’s important to note that the terms food allergy and food intolerance are often confused, but they are two very different things! To set the record straight, a food allergy affects 1-2% of the adult population and happens when our immune system mistakes a protein in the food as dangerous and mounts an attack. Food allergies can be life-threatening and need to be managed by your medical team. Keep an eye on my next post which will deal more with allergies.
A food intolerance does not involve our immune system, but maybe caused by difficulty digesting a certain food. Take lactose intolerance as an example. This is caused by a lack of the enzyme ‘lactase’ in the body, whose job it is to break down lactose. The lactose is not digested properly because of this and causes bloating and diarrhoea as a result.
Many food intolerances are not well understood, making diagnosis and treatment more difficult.
The most common food intolerances that tend to pop up are lactose, gluten/wheat, salicylates, sulphites, histamine and FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). Unfortunately, there are no reliable tests available for diagnosing intolerances. Apart from breath tests for lactose intolerance.
Testing for intolerances
Let’s delve a bit more into IgG testing, which is a test that is widely available online. This test claims to diagnose food intolerances by testing for IgG antibodies in a sample of your blood. Following exposure to a particular food. What we know is that these IgG antibodies are actually a marker of previous exposure to a food. However, there is no link between IgG antibodies and food intolerance, so save your pennies.
Inaccurate intolerance tests can often leave people following unnecessarily restrictive diets, which can have long-term consequences, as it puts them at risk of nutritional deficiencies.
It’s advised that if you suspect you may have a food intolerance you consult your GP to rule out any other potential causes of your symptoms, such as coeliac disease.
If you get the all-clear and it’s thought you may have a food intolerance, the so-called ‘gold-standard’ for identifying intolerances is an exclusion diet.
Diagnosing the intolerance
You can start by keeping a food and symptom diary. This will help you to pick out any possible cause of your symptoms. Once you’ve identified a potential culprit, try removing it from your diet for four weeks. You may wish to work with a dietitian, particularly if you think you may have multiple intolerances.
If you feel an improvement after the elimination period, it is important to reintroduce the food to confirm that it was the cause of your symptoms. Start by having a small portion of the food in question. Build up to your normal portion size over a few days. Even if this process confirms that you have a food intolerance, they are often dose-dependent. Meaning you may be able to manage a small amount of the food you are intolerant to without any problems, so you may not have to avoid it completely.
For more information on food allergies and intolerances from reliable sources, see here
Aoife McDonald is a registered dietian based in Cork with a special interest in gut health, IBS and public health and promotion. For more information visit TheDigestiveHealthClinic or check out her Instagram account, which mainly focuses on IBS and gut health
Read more: 5 tips for better gut health