Low FODMAP Diet for IBS and Endo. What can go wrong?

You’ve likely encountered various diets claiming to soothe digestive woes like abdominal pain, gas, bloating, constipation, or diarrhoea, all common symptoms of IBS and Endometriosis. While these diets can offer relief, it's crucial to follow them under the guidance of a healthcare professional to avoid common pitfalls that might hinder their effectiveness or compromise your intake of essential nutrients.

One diet that stands out in managing digestive symptoms, especially for those with Irritable Bowel Syndrome (IBS), is the Low FODMAP Diet. Developed by researchers at Monash University in Australia, this diet is structured in three phases. The initial 'restriction' phase, lasting 2-6 weeks, eliminates foods high in FODMAPs. This is followed by the 'reintroduction' phase, where foods are gradually added back to identify specific triggers. Finally, the 'maintenance' phase incorporates high FODMAP foods that didn't cause symptoms, allowing for a more personalized and balanced diet.

Endometriosis and the Low FODMAP Diet

Symptoms of endometriosis, a chronic inflammatory condition where endometrial-like tissue grows outside the uterus, often overlap with symptoms of IBS, and many people are diagnosed with both. This means individuals with endometriosis are more likely to experience gas, bloating, nausea, abdominal pain, constipation, or diarrhoea. One reason for this link is visceral hypersensitivity, which refers to increased sensitivity to abdominal changes that the brain interprets as pain, common in both IBS and endometriosis. These changes can include increased gas production through the fermentation of FODMAPs. Studies have shown the low FODMAP diet is effective in reducing bloating, pain, gas, and bowel motion changes in many individuals with endometriosis.

First of all, what are FODMAPs? 

FODMAP is an acronym used to describe a group of short chain carbohydrates that react differently in the digestive system to most other food molecules. Instead of being digested and absorbed in the small intestine, FODMAPs attract water into the intestines from the surrounding tissue, and travel to the large intestine where they begin to ferment with the help of our gut bacteria. This fermentation process produces gas which puts pressure on our intestinal walls causing bloating and distension. The gas is also responsible for abdominal pain and changes in bowel habits due to the reaction from nerve endings surrounding the large intestine. 

It is important to note that not all people will experience digestive symptoms when eating foods containing FODMAPs, and many other factors go into the experience of these symptoms, including hydration, exercise levels, stress, presence of small intestine bacterial overgrowth, and level of gut sensitivity. 

What can go wrong?

1. Staying in the restriction phase of the low FODMAP diet for too long

The goal of the Low FODMAP diet is to figure out which foods trigger IBS symptoms. This is done by slowly reintroducing high-FODMAP food back into regular meals and recording any symptoms that may occur. Although it may seem daunting to reintroduce foods that may trigger pain or other symptoms, it is an important part of the process to ensure you can determine which foods to avoid in the future, and which foods are more easily absorbed by your body. Your dietitian will talk you through each step of the diet, including the appropriate length of each phase.

2. Choosing not to substitute restricted foods with Low FODMAP alternatives

When removing high FODMAP foods in the first phase of the diet, it is important to swap them with different foods that will provide you with the same energy and nutrients. For example, when removing dairy products from your diet, make sure to swap them for fortified plant-based alternatives to ensure you are getting a healthy intake of protein and calcium. Unintentionally decreasing your overall energy intake due to removing usual foods you may eat such as bread or pasta, may cause energy imbalances leading to even more issues such as fatigue or loss of menstruation.  

3. Removing all sources of prebiotics and probiotics

Following the Low FODMAP diet may impact on your gut health as many good sources of prebiotics and probiotics are also high in FODMAPs. However, swapping these with low FODMAP alternatives is possible and should be done to maintain a healthy gut microflora. Low FODMAP probiotic foods include miso, tempeh, lactose-free yoghurt or kefir, and red cabbage sauerkraut.  Low FODMAP prebiotic foods include kiwifruit, almonds, oats, and buckwheat flour.  Learn more about prebiotics and probiotics here. 

4. Limiting fibre intake 

Restricting high FODMAP foods that are also high in fibre including some vegetables, fruit, and grains can actually lead to IBS-like symptoms without FODMAPs being the cause. This is due to the important role that fibre plays in our digestive system. Fibre adds bulk to our stool (poo) by drawing water into the intestines. This makes it easier for our large intestines to pass bowel motions, as well as keeping the consistency and timing of bowel motions regular (as opposed to having constipation or diarrhoea).

Because fibre requires water from the surrounding tissue to do its job in the digestive system, it is vital that you are drinking water regularly throughout the day and limiting your caffeine and alcohol intake as both of these will naturally dehydrate your body. 

5. Giving up if the Low FODMAP diet is ineffective

If you have recently completed the Low FODMAP diet and have not found it to be effective for identifying the cause of your digestive issues, you are not alone. In fact, for 1 in 4 people, the Low FODMAP diet is not effective, however there are many other strategies that could be. These can include stress management techniques, changes to exercise levels, and other changes to diet including alcohol or caffeine intake, fibre intake, restriction of spicy foods, or trialing a gluten free diet. Your digestive symptoms may also be a sign of endometriosis due to the shared symptom of visceral hypersensitivity in the abdomen. If you also experience some of the symptoms below, endometriosis could be the underlying cause of your digestive discomfort, and may require additional management strategies to lessen the impact of symptoms on your overall wellbeing.

What does this mean for me?

The Monash University Low FODMAP Diet is effective for the management of Irritable Bowel Syndrome but should be followed with the guidance of a Monash FODMAP trained dietitian to ensure it is completed correctly. Although it seems like a fairly simple diet to follow, there can be a lot of misinformation online which sometimes causes mistakes to be made, reducing its effectiveness and leading to insufficient intake of some essential nutrients.

Maintaining a variety of foods from different food groups in your diet will ensure you are maintaining a healthy intake of energy and essential nutrients. It is important to remember that foods high in FODMAPs aren’t the always the cause of IBS-like symptoms, but there are many ways to get back to feeling your best.

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