identifying food intolerance: how to do it?

The term ‘food intolerance‘ is becoming increasingly common and more and more people seem to have a food intolerance. Food intolerances are different to food allergies as they don’t involve an immune reaction. Instead, intolerances are when you have difficulty digesting certain foods, which can lead to digestive symptoms.

Food intolerances are common, with more than 20% of people in Western countries suffering from a food intolerance. A correct diagnosis of a food intolerance is important so that you do not have to avoid foods unnecessarily. This can cause deficiencies. For example, there are many people who think they react to gluten and then avoid all gluten-containing products, but a real diagnosed gluten intolerance (celiac disease) is very rare.

identifying a food intolerance

The symptoms of food intolerances don’t always emerge right after eating and sometimes can take several hours to come about. This makes it difficult to pinpoint the culprit and often leads to unnecessary restriction of foods. By diagnosing a food intolerance, it can reduce your symptoms, diversify your diet, and bring back the joy of eating.

There are a few ways to discover if you have a food intolerance:

• Doing the elimination-provocation diet
• Breath testing
• Keeping a food diary
• Using digestive enzymes

elimination-provocation diet

The most reliable way of diagnosing food intolerance is the elimination-provocation diet which is followed under the supervision of a dietician. An elimination diet is followed over a period of time, usually 3-4 weeks.

If lactose intolerance is suspected, a lactose-free or low-lactose diet is followed for a number of weeks. If after a few weeks the symptoms have disappeared or have greatly diminished, lactose intolerance can be diagnosed. This is followed by provocation, in which foods containing lactose are reintroduced into the diet. Like with breath testing, this helps to find out what amount you can digest and thus to draw up a personal diet.

The FODMAP elimination-provocation diet is also often used, especially when multiple intolerances are suspected, or when it is unclear which foods are causing the symptoms. Read here the blog: 10 tips on the low FODMAP diet.

breath testing

Breath testing has been used by the medical field for decades and is one of the best ways to diagnose a food intolerance. By measuring the amount of hydrogen or methane on your breath, it can help detect if a food has been digested well or not.

When we eat food, it travels through the stomach and into the small intestine. It’s here that we break down the food so that we can absorb the nutrients into our bloodstream. If a food is not digested well and is not broken down, it continues to the large intestine where it is fermented by the bacteria. This fermentation results in gas production. Fermentation is normal and healthy but when we don’t digest food well, it can lead to lots of gas and water to build up. This build can result in painful symptoms. Breath testing can measure the amount of gas produced, as the gas in our gut travels into our bloodstream and is exhaled on our breath. Breath testing can be used to determine whether your symptoms are linked to the poor digestion of a particular food.

You can do a breath test at the hospital, or with a small device at home. Nowadays breath testing is much more accessible and not only isolated to hospital settings. FoodMarble for example has created pocket-sized personal breath testers, AIRE 1 and AIRE 2, that can measure hydrogen and methane levels from the comfort of your own home. You can test how well you absorb the likes of lactose, fructose, sorbitol, and inulin, as well as test your fermentation levels in response to your normal diet.

With most food intolerances, you should be able to tolerate some amount of the food without experiencing symptoms. By using AIRE 1 or 2, you can test what this level is for you. As well as the breath test device, the FoodMarble app also allows you to track your meals, symptoms, stool, sleep and stress to give you insights that can help you manage your digestive problems over the longer-term. It is also possible to seek guidance from a dietitian as well, when using the Foodmarble device, for even more reliable results and help with establishing a personalized diet.

keeping a food diary

A food diary can also give you a lot of insights into the foods that may be triggering your symptoms. It works by keeping a diary for a few days or weeks where you record all your meals and symptoms. Analysing the diary might reveal patterns that may help determine your food triggers. For example, if after every time you eat onion and garlic you develop symptoms a few hours later, then it is possible that you have a fructan intolerance.

Our intolerance check can also be a great tool for checking this: fill in which foods you think regularly give you symptoms. Afterwards you will receive a report with the intolerances that might be at play.

Note: If you suspect that your symptoms might be a food allergy, are caused by gluten (celiac disease), or think something else may be wrong, then always consult your doctor!

digestive enzymes

Have you not (yet) been diagnosed with an food intolerance, but you strongly suspect one? And do you want to know for sure whether your suspicion is correct? Then you can do an experiment with supplements, specifically supplements containing digestive enzymes. Do you suspect for example that you have lactose intolerance? Then try lactase tablets with the lactase enzyme that can break down lactose. If you take these tablets before each meal containing lactose, the lactose will be broken down properly. If you notice a difference and don’t experience your usual symptoms, then this points to you being intolerant to lactose.

If you are in doubt or would you like personal advice then feel free to contact your doctor or a dietician. Our own Intoleran dieticians can also advise you on the use of supplements in cases of food intolerance.

references:

Y. Zopf, Dr. Med. Et al. The Differential Diagnosis of Food Intolerance. Dtsch Arztebl Int. 2009 May; 106(21): 359–370. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2695393/

G.I. Skodje et. Al. Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity. Gastroenterology. 2018 Feb;154(3):529-539.e2.  https://pubmed.ncbi.nlm.nih.gov/29102613/

M. C. E. Lomer. Review article: the aetiology, diagnosis, mechanisms andclinical evidence for food intolerance. Aliment  Pharmacol  Ther 2015;41:262–275 https://onlinelibrary.wiley.com/doi/epdf/10.1111/apt.13041

C. De Geyter et al. Hydrogen and Methane Breath Test in the Diagnosis of Lactose Intolerance Nutrients. 2021 Sep; 13(9): 3261. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8472045/

Satya Vati Rana, Aastha Malik. Hydrogen Breath Tests in Gastrointestinal Diseases. Ind J Clin Biochem (Oct-Dec 2014) 29(4):398–405 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4175689/pdf/12291_2014_Article_426.pdf