The Role of the Low FODMAP Diet in IBS Symptom Management

We do not know what causes IBS, however, we know from scientific studies that consuming a diet low in ‘FODMAPs’ may help people with IBS  find relief from their gastrointestinal symptoms.

The term FODMAP is an acronym that stands for:

Fermentable

Oligosaccharides

Disaccharides

Monosaccharides

And

Polyols

FODMAPs are fermentable short-chain carbohydrates that are often poorly absorbed in the gut and cause undesirable gastrointestinal symptoms in people with IBS. Such sugars are commonly found in legumes, wheat, rye, grains, fruits and vegetables, and some processed foods.

For people with IBS, the movement of FODMAPs from the small bowel into the large bowel means that the resident bacteria in the large bowel starts to ferment the FODMAPs, producing gas and bloating. Then, excess water being drawn into the bowel causes diarrhea, abdominal pain, discomfort, and further bloating.

Generally speaking, we naturally lack the enzymes required to digest certain FODMAPs. However, for those with IBS, a phenomenon called 'visceral hypersensitivity’ is the reason why FODMAPS can cause such disturbing symptoms.

Breaking down FODMAPs

Fermentation occurs in the gut when bacteria present in the large intestine consumes the short-chain carbohydrates.

Oligosaccharides are mainly fructans and GOS, which are malabsorbed in the gut due to our lack of fructan and GOS-degrading enzymes. These are highly fermentable by gut bacteria, causing gas production, abdominal pain, and bloating in IBS.

Disaccharides refers to lactose, a poorly digested double-sugar present in those lacking the lactose-degrading enzyme known as lactase. This is common in people of Asian and Mediterranean backgrounds, and also in diseases causing intestinal inflammation (such as Crohn's disease), with prevalence increasing with age.

Most people are able to digest lactose and don't need to follow the lactose component of the low FODMAP diet. If you're unsure as to whether or not this applies to you, chat to your doctor or an accredited/registered dietitian.

Monosaccharides represent fructose, the smallest FODMAP sugar. When fructose is present in greater quantities than glucose in your gut, this osmotic imbalance enables ready-attraction of water into your intestine, causing pain, bloating, large amounts of diarrhea, and altered transit through the gut.

‍Polyols commonly include mannitol, maltitol, xylitol, and sorbitol, and are often found in sugar-free chewing gum, sugar-free products, and in some fruits and vegetables. These molecules are ‘sugar alcohols’, and are similar to fructose in that these are poorly absorbed in the gut and may cause the same effects as excess fructose.

Here are some foods high in FODMAPs:
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• ‍Polyols: Avocado, button mushrooms, green apples, apricot, blackberries.
• ‍Fructose: Watermelon, mango, asparagus, peaches, plums, nectarines, honey.
• ‍Fructans: Onion, garlic, ripe banana, figs, multigrain and rye bread, wheat-based gnocchi.
• ‍Lactose: Cow's milk, natural Greek yoghurt, vanilla ice cream (two scoops).
• ‍GOS: Cashews, pistachios, soy protein, silken tofu, red kidney beans, pinto beans, falafel.

Here are some foods low in FODMAPs:

• ‍Vegetables: Cucumber, iceberg lettuce, oyster mushrooms, olives, spring onion (green tops only), unpeeled potato, jap pumpkin, radish.
• ‍Fruits: Navel oranges, starfruit, raspberries (under 30), two small green kiwis, six grapes, clementine, one medium-firm banana.
• ‍Grains: Unprocessed bran, gluten-free bread, rolled oats, spelt sourdough, one slice white bread, gluten-free flour, gluten-free pasta, quinoa, brown and white rice.
• ‍Lean meat/alternatives: Tempeh, one cup firm tofu, egg replacer, 1/4 cup rinsed canned chickpeas and beans, brazil nuts, chestnuts, macadamia, peanuts, pine nuts, chia seeds, hemp seeds, sesame seeds.
• ‍Dairy: Lactose-free milk, butter, cheddar, feta, parmesan, nut milk, lactose-free yoghurt

Good to know: rinsing legumes prior to eating helps to wash out the FODMAPs as they are water soluble.

Download the Monash University FODMAP Diet app for more information about foods high and low in FODMAPs. You'll learn which foods have been tested by the Monash FODMAP team and categorised via a traffic light system for FODMAP safety.

Low FODMAPs for IBS symptom management

Up to 15% of the Western population experience IBS, and you're likely to make at least five annual visits to the doctor. A diet high in FODMAPs has been found to increase symptoms of excessive flatulence, abdominal cramping, constipation, bloating, and diarrhea in individuals diagnosed with IBS.

Current research shows that the low FODMAP diet is effective in relieving IBS symptoms in up to 86% of patients.

Fun fact: hypnotherapy equaled the low FODMAP diet in symptom relief, and you can try both at the same time.

Note that the common symptoms of IBS (abdominal pain, bloating, and alternating bowel habits) can overlap with those typical of Coeliac disease, colon cancer, Inflammatory Bowel Disease (IBD), endometriosis, and Polycystic Ovary Syndrome (PCOS) among others. This means it's imperative that you get a clear and accurate diagnosis to make sure you receive appropriate treatments and manage your IBS with the right tools.

If you are unsure of the cause of your symptoms, talk to a healthcare professional.

‍The purpose of a low FODMAP diet

The purpose of the low FODMAP diet is to relieve symptoms associated with IBS. The diet is internationally recognised as the accepted research-backed IBS dietary management strategy.

The diet includes a three-phase process:

Phase 1: FODMAP elimination. The purpose of phase 1 is to remove all FODMAPs from your diet for a short period of six to eight weeks in order to identify your key food triggers. This phase is not intended to be maintained long term.

Phase 2: FODMAP reintroduction. Small amounts of high FODMAP foods are brought back into your diet in a gradual incremental process, testing tolerance to specific FODMAP groups.

Phase 3: Personalization. Phase 3 involves liberalizing your diet to optimize long-term dietary variety, and testing and retesting tolerance so you can eat a wide range of foods.

Before attempting a structured FODMAP diet, it’s important you first talk to a dietitian or your doctor.

Undertaking a low FODMAP diet on your own isn't recommended as it can lead to a misdiagnosis or self-diagnosis of other conditions, you could harm your intestinal microbiome, and you may eliminate the wrong foods resulting in nutrient deficiencies.

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Low FODMAP Pad Thai recipe

Here’s one of our favorite Low FODMAP meals, to give you a taste of how good gut-friendly food can be. This Pad Thai recipe is the perfect dinner option for those in a rush and looking for a delicious garlic-free, onion-free, easy-to-prepare low FODMAP meal.

Serves: 2 people

Prep time: 15 minutes

Cook time: 10 minutes

Ingredients

80g flat rice noodles*

2tbs fish sauce*

2tbs oyster sauce*

4tsp brown sugar

2tsp coconut oil

1 egg, lightly beaten

200g beef stir fry

1 cup bean shoots

1½ tbsp unsalted peanuts*

1 tbs chives

1 lime

‍Method

1. Soak flat rice noodles in boiling water and set aside.

2. Combine the fish sauce and oyster sauce with the brown sugar and set aside.

3. Heat half the oil in a wok on high heat. Add the egg to fill the bottom of the pan and cook for 2 minutes. Remove from the wok and thinly slice. Set aside.

4. Add the remaining oil. Add the beef and cook until evenly browned.

5. Drain the noodles before stirring the noodles and sauce into the beef mix. Stir until sauce thickens.

6. Stir in the chives, bean shoots, egg and chopped Alfie's unsalted peanuts.
7. Serve with cut up lime wedge for added flavour.

All ingredients are in low FODMAP serving sizes according to the Monash University Low FODMAP Diet smartphone App.

Happy cooking!

*You can find these ingredients at Fodshop.

About our guest writer

This article was contributed by our friends at the FodShop, an Australian-based online FODMAP expert and nutritionist-run shop.

FODMAP-trained Accredited Practising Dietitians frequently utilize FodShop as a resource to select suitable food products for people undertaking a FODMAP elimination diet, as many are low FODMAP tested and certified by Monash University.

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