WHAT ARE FODMAPS?
FODMAPs are small carbohydrates in our foods that are not digested very well. They stay in our gut and attract water, then reach the large intestine where they are fermented by our gut microbes. This produces gas.
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The extra water and gas in our gut can cause gut distension (bloating) and cause pain as well as changing the motility of the gut- speeding it up (diarrhoea) or slowing it down (constipation).
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The gut has many, many nerves and is often referred to as the 'gut brain'. People with IBS (irritable bowel syndrome) are said to have nerve endings that are overactive or on high alert so are are extra sensitive to the stretching of the gut wall due to the extra water and gas in the gut. This is called visceral hypersensitivity.
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FODMAPs are also called probiotics which means they are healthy foods for our gut microbes that help our gut health. That means while we reduce FODMAPs in the diet to manage symptoms, in the long term we want to find a balance that helps manage symptoms as well as providing a level of FODMAPs to the gut that we can tolerate.
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Monash University has created a video that explains how FODMAPs can cause symptoms.
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Monash University FODMAP video explainer
Low FODMAP diet helps you manage your IBS symptoms
One in seven adults suffers from Irritable Bowel Syndrome (IBS) so luckily most (70%) can find relief by reducing the FODMAPs in the diet (1).
Relief can occur commonly within days or the first week of starting the low FODMAP diet although it can take longer if sneaky FODMAPs are still popping up in the diet.
For those who do not benefit from the low FODMAP diet, food chemical intolerance could be considered.
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For those who get symptom relief- YAY! It does not stop there though- although it is temping to sit with the low FODMAP diet, it can affect the diversity of bacteria in the gut. To support gut health, we need to move onto the next 2 stages of the low FODMAP diet, challenges and re-introduction.
Btw FODMAP stands for:
F ermentable (gut microbes ferment them)
O ligo-saccharides (long chain fructose)
D isaccharides (lactose= milk sugar)
M ono-saccharides (fructose)
A nd (easy one!)
P olyols (sugar alcohols).
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FOODS HIGH IN FODMAPs
FRUCTOSE
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Fructose is the smallest FODMAP and is commonly known as fruit sugar. True to its name, fructose is found in fruits such as apples, pears, watermelon and mango but it is also present in many other foods such as honey.
Fructose is absorbed across the gut wall via two different ways. One way is via GLUT 2 (a transporter) and this method is super fast and efficient. However, some people have reduced GLUT 2 ability so fructose transport across the gut is reduced. The remaining slower transporter piggy backs one fructose for every glucose which means that while there is some fructose absorption, the fructose can build up in the gut and spill over into the large intestine.
This means that foods that contain more fructose than glucose may be causing you issues. Food that have more fructose than glucose include apples, mango, watermelon, many fruit juices, honey and asparagus.
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LACTOSE
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Lactose intolerance is due to not having enough of the enzyme LACTASE which breaks down lactose.
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Probably the easiest FODMAP to avoid as so many lactose free products are available such as lactose free milk, lactose free yoghurt, lactose free cream cheese, lactose free custard, lactose free ice cream and in fact most cheeses we eat contain very little lactose such as cheddar, feta tasty, parmesan and even soft cheeses such as camembert.
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Not all people with FODMAP sensitivities will have lactose intolerance and if this sounds like you, then you can undertake the Low FODMAP diet without reducing your lactose.
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POLYOLS (Sorbitol & mannitol)
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Polyols are called sugar alcohols No, they are not alcoholic- the name just relates to their chemical structure. They are small FODMAPs that are not able to be broken down so make it in an undigested form to the large intestine where microbes will readily ferment them.
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You find polyols in many fruits such as apricots, many peaches, plum, pears, cherries and apples as well as in vegetables such as mushrooms, cauliflower and snow peas.
Polyols are often used as additives in:
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Diet products: since polyols give a sweet taste but are not absorbed well they are really useful as artificial sweeteners in diet products such as Extra chewing gum and some mints
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Liquid medications such as liquid cough mixtures may harbour some polyols such as sorbitol.
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FRUCTANS & GOS (oligosaccharides)
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Fructans and GOS are still small carbohydrates but larger than the other FODMAPs. As we lack the enzymes to break down fructans and GOS, it remains undigested in our gut and reaches the large intestine where the microbes have a field day! Nom nom! This is quite a normal process, as it is important that we feed our gut microbes.
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You find fructans in wheat, as well as spread across many foods such as many vegetables, including onion and garlic.
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Wheat fructans: the low FODMAP diet is not wheat or gluten free, small amounts of wheat are tolerated and gluten is tolerated. It is the wheat fructans we are looking to reduce. There are so many alternatives low in FODMAP such as wheat sour dough and many low FODMAP certified breads and even a certified low FODMAP wheat flour! For where there are no specialised Low FODMAP wheat alternatives, gluten free products can often be used.
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Onion & garlic fructans: finding alternatives to onion and garlic is imperative and garlic infused oil may become your best friend, along with the green tops of spring onions. Hidden garlic and onion is trickier- it can be in stocks and sauces but these days there are so many reduced onion and garlic alternatives.
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GOS is in legumes (beans- not green beans though). So while most beans such as baked beans and red kidney beans and lentils can be an issue, there are some exceptions. For example tinned lentils (drained and rinsed) is low FODMAPs for a serve, and some other beans can be low FODMAP for reduced serving sizes.
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REFERENCES
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Halmos, E.P., et al., A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology, 2014. 146(1): p. 67-75 e5.
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CK Yao, Jessica Biesiekierski, Sue Shepherd, Peter Gibson, Eastern Health Clinical School, Monash University, Box Hill Hospital, Melbourne, Australia.
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Distrutti, E., Monaldi, L., Ricci, P. & Fiorucci, S. Gut microbiota role in irritable bowel syndrome: New therapeutic strategies. World J. Gastroenterol. 22, 2219–2241 (2016).
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Barrett, JS. How to institute the low-FODMAP diet. Journal of Gastroenterology and Hepatology 2017; 32 (Suppl. 1): 8–10. Retrieved from: http://linkis.com/wiley.com/urRXY. retrieved on 2017/07/22
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