What is the low-FODMAP diet? Is it food fad or food fact? Why you should approach with caution

It’s the mind-boggling acronym being hailed as “the next gluten-free”. But WTF are low-FODMAP foods, and are they eally a miracle ‘cure’ for chronic gut problems?

Everything you need to know about FODMAP, who might benefit from a diet low in the thingummies the acronym stands for (and who won’t), and where you should go for accurate advice.

What are FODMAPs?

FODMAPs are carbs that get broken into sugars as they get digested. The acronym stands for Fermentable, Oligo- Di- Mono-saccharides And Polyols.

Oligo-saccharides include fructans (contained in wheat, rye, garlic and onion) and galacto-oligosaccharides (pulses and legumes and some nuts, particularly pistachios and cashews). Oligo-saccharides in general are not well absorbed by the body.

Lee Martin, a research dietitian specialising in FODMAPs at Kings College London, explains: “Humans don’t have the enzyme needed to break down oligo-saccharides, so when they hit your large bowel it’s the bacteria that digests them. You get fermentation from bacteria, which can lead to gas, bloating and wind pain. It can also draw water into the large bowel, causing diarrhoea.”

Then there are the disaccharides and monosaccharides, which some people absorb better than others. Lactose is a disaccharide, so this refers to all animal-milk products such as yoghurt, milk and cheese.

Fructose is a monosaccharide and the gut issues occur when foods – such as honey, fruit juices or mangoes – have fructose in excess of glucose.

Lastly are the polyols, or ‘sugar alcohols’, for example sorbitol (found in sugar-free chewing gum and some fruits and vegetables, including avocados and broccoli) and mannitol (in vegetables including sweet potatoes and cauliflower).

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Where has all this come from?

Definitely not from Gwyneth Paltrow, we promise. The low-FODMAP diet was developed at Melbourne’s Monash University by professor of gastroenterology Peter Gibson and dietitian Dr Susan Shepherd. Shepherd conducted a randomised trial into the plan for Irritable Bowel Syndrome sufferers as part of her PHD research in 2008; it proved effective and the rest, as they say, is history.

In the UK, Dr Peter Irving, consultant gastroenterologist at Guy’s & St Thomas’, has been responsible for spearheading FODMAP research after working for a period at Monash.

Who can benefit from low FODMAP?

People with IBS are the key group to benefit from the low-FODMAP diet, with as many as 70 per cent of patients reporting an improvement. Martin describes the results of using it in clinical practice as “amazing”.

So don’t go jumping on the FODMAP bandwagon if you get a bit windy after a bean cassoulet. “The whole point about it is that it’s designed for people who have been diagnosed with IBS,” says Martin.

“If you’ve just got a few gastrointestinal symptoms then perhaps don’t have a whole can of beans, or a whole head of broccoli.”

It is also important not to self-diagnose gut symptoms without seeking medical help. A diagnosis of IBS can be tricky – it is a gastrointestinal syndrome with no organic cause – but it is vital to first rule out other, potentially more serious, disorders such as Crohn’s or Coeliac disease.

Early research suggests that low FODMAP could also be beneficial as a supplementary management plan for those with Coeliac or Crohn’s disease, as well as for gut conditions such as ulcerative colitis and Non-Coeliac Gluten Sensitivity [NCGS]; that is, people who have a reaction to gluten but no markers for Coeliac disease.

In a recent study, Monash University researchers gave people who believed they had NCGS both a low-FODMAP and gluten-free diet to reduce their symptoms. In a blind challenge they then reintroduced both FODMAPs and gluten.

Martin says: “When gluten was introduced they had no symptoms, but when they had FODMAPs they did.”

The research needs to be replicated, but there is growing evidence that it is not gluten that causes gastrointestinal symptoms for non-Coeliac sufferers, but FODMAPs.

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FODMAP is not a diet for life

One of the major misconceptions is that eliminating FODMAPs is a long-term plan. In fact, high FODMAP foods should only be eliminated for eight weeks, followed by a gradual reintroduction under the supervision of a registered dietitian, ideally one trained in FODMAPs by Kings College London.

After eight weeks of cutting out high-FODMAP foods and reducing gut symptoms comes the reintroduction phase. The patient is ‘challenged’ in high-FODMAP foods to assess what his/her personal level of tolerance is. For example, on day one honey and mango may be reintroduced, with a double portion the following day and so on, to see what symptoms occur and when.

Martin says: “The whole point is that in the long term you can continue to have all of these foods but know what the appropriate portion size and combination for you will be. We’re not talking about cutting out FODMAPs for life.”

The future for FODMAPs

The hope is that new NICE guidelines due out in 2016 will approve the low-FODMAP diet as a first-line treatment for IBS. Addressing IBS for the one in five sufferers in the UK would be a huge boost. Research shows that people with IBS have a lower quality of life than people with diabetes.

The next step for Kings College researchers is more investigation into the long-term effects of the low-FODMAP management plan.

Meanwhile, in the food sector, FODMAP is fast becoming the new buzzword. In Australia, Dr Sue Shepherd has launched a series of products including pasta sauces, curries, paella kits and confectionery.

In the UK, Laura-Daisy Jones, a food scientist at Mintel, says: “Companies should keep an eye on FODMAP products and research as, although very niche at the moment, they could become a rival for gluten free.”

Where to go for FODMAP advice

For those who struggle to get access to a FODMAP-trained dietitian via their GP, resources include UK charity the IBS Network and the Monash University Low-FODMAP diet app for smartphones.

The app lists foods using a traffic light system. Foods marked red are high in FODMAPs and should be avoided; orange foods are moderate and may be tolerated by some; and green foods are low and safe for consumption. It also includes recipes, meal ideas and a seven-day challenge where patients can record their food and symptoms to show their doctor or dietitian.

The app’s pioneer, Professor Gibson, says: “Much of the information on the internet is no longer accurate because it’s out of date. Our data is evidence based, it’s been peer reviewed and published in major journals around the world so it can be trusted.”

Useful FODMAP websites

The list of Kings College London FODMAP-trained dietitians

King’s College London’s FODMAP website