5 Considerations before starting your child on the low FODMAP diet


The low FODMAP diet was designed by Monash University. Their research has shown that the low FODMAP diet is effective in improving IBS symptoms in 3 out of 4 people. Other studies have found similar results (1). Whilst the research has been primarily conducted in adults, there has been promising results from two small randomised controlled studies in children (2, 3). 


What are FODMAPs?

FODMAPs is an acronym for fermented oligosaccharides (fructans & galactoligosaccharides), disaccharides (lactose), monosaccharides (fructose) and polyols (mannitol & sorbitol). In simple terms they are a group of short chain carbohydrates (sugars) that are rapidly fermented in the gut.

FODMAPs are found in a wide variety of foods including wheat/rye/barley based products, dairy products, legumes, nuts (e.g. pistachios and cashews), various vegetables (e.g. onion, garlic, mushrooms, cauliflower, asparagus and artichokes) and fruits (e.g. stone fruits, apples, pears and watermelon).


How do FODMAPs trigger IBS symptoms?

When we eat FODMAPs they travel through our digestive system. Once they reach our small intestine FODMAPs which are not completely digested or absorbed causes water to be drawn into our small intestine. The FODMAPs then pass into our large intestine where gut bacteria use the FODMAPs as a fuel source to survive. As the bacteria rapidly ferment FODMAPs they produce gas. The excess gas and water retention causes the intestinal wall to stretch and expand. In children with IBS this can trigger abdominal pain or discomfort and changes in bowel habits including diarrhoea and/or constipation. 


What steps are involved in completing the low FODMAP diet?

The low FODMAP diet consists of three steps. The first step is the low FODMAP elimination diet where high FODMAP foods are swapped with low FODMAP alternatives for a period of 2-6 weeks. For children a simplified approach is recommended rather than a strict elimination approach where only frequently consumed very high FODMAP foods are removed. The second step is reintroduction where structured FODMAP challenges are completed using one FODMAP group at a time to determine tolerance levels to each FODMAP subgroup. The last step is personalisation where FODMAPs which were well tolerated during the reintroduction step are reintroduced back into the diet.


What do you need to consider before starting your child on the low FODMAP diet?  

1. Has your child been assessed by their doctor and diagnosed with IBS?

Before starting your child on the low FODMAP diet it is essential that they have been assessed by either their general practitioner, paediatrician or gastroenterologist to ensure a correct diagnosis of IBS. Unfortunately many conditions can present similar to IBS such as coeliac disease and inflammatory bowel disease, which is why it is so important to have your child correctly assessed. For more information on IBS diagnosis and red flags check out my IBS blog.


2. Have you implemented first line IBS dietary and lifestyle strategies?

It is important to consider first line IBS dietary and lifestyle strategies before commencing your child on a low FODMAP diet. For some children simple dietary changes such as modifying eating patterns including meal size, ensuring adequate fibre and fluids and reducing intake of fatty foods, fruit juice and soft drinks can help alleviate IBS symptoms. Ideally we want to avoid elimination diets in children if possible due to the potential impact on nutritional intake, growth and relationship with food.


3. Is your child a fussy eater or are there any growth concerns?

If your child is a fussy eater or has any other feeding difficulties you will need to first assess whether there are suitable alternatives that your child will eat. If there is limited ‘safe’ or ‘preferred’ foods there is a high risk of nutritional deficiencies. In this instance the diet may be contraindicated for your child. In addition if there is any growth concerns it is important to consider whether the low FODMAP diet will further compromise growth.


4. Does your child have a history of disordered eating or eating disorder?

The low FODMAP diet is contraindicated in children with a history of disordered eating and eating disorders or in children at high risk of developing an eating disorder. If this is relevant to your child it is important to assess their general dietary intake in terms of nutritional adequacy and potential triggers, however non-diet therapies including medications and psychological therapies such as counselling, cognitive behavioural therapy and gut directed hypnotherapy are recommended as the most suitable treatment approaches.


5. Are you working with a qualified paediatric dietitian specialised in IBS?

Monash University who developed the low FODMAP diet recommend that all children on the diet are supervised by a qualified paediatric dietitian specialised in IBS. It is very confusing trying to navigate the low FODMAP diet alone and can be harmful to your child’s health if the diet is not followed correctly. A dietitian will be able to support you through each step of the diet and ensure your child’s diet is still nutritionally balanced to help support their growth and overall gut health. They can also help troubleshoot if you are not getting results with your child on the low FODMAP diet.


Want to feel more confident managing your child’s IBS so they can find relief from bloating, pain, sluggish or unpredictable bowels? Click HERE to book an appointment. We also have a special Kids IBS & Low FODMAP Facebook support group which you can join HERE.