Billed as ‘An international meeting on food, diet and gastrointestinal health’ with a theme of ‘Food Intolerance: FODMAPs, gluten and beyond’, the GASTRODIET 2015 conference took place earlier this month at the Monash University Campus, Prato, in Italy. Alex Gazzola draws on the many live tweets published during the two-day meeting and rounds up the key points from some of the presentations.

Day 1, Monday 2nd November, 2015

Dr William Shey, University of Michigan Health System, US
The emergence of diet as a therapy for IBS

Over the last few years there has been a shift away from drugs - which aren’t that effective for many patients - towards diet as the primary therapy for irritable bowel syndrome.

In a survey, two-thirds of UMHS patients believed food triggered symptoms, effecting their quality of life: because of their bowel problems, 62% said they have to watch the amount of food they eat, 74% said they have to watch the kind of food they eat, and 51% said they feel frustrated they can’t eat what they want.

Dr Shey said that 90% of gastroenterologists surveyed believed diet to be as good as or better than medication but rarely referred patients to dietitians – even though there would be huge benefits to the patient.

Food has a huge effect on the gut and gut symptoms, among which osmotic, chemical, mechanical, neuroendocrine, probiotic, prebiotic, fermentation by-products, pH and microbiome. Psychological factors (depression, anxiety, nocebo) may be involved, and there are effects on motility, visceral hypersensitivity, dysbiosis, gut permeability, brain-gut interaction and immune activation.

Dietitians are vital in IBS management, and can improve quality of life and reduce symptoms in patients – but more research is needed to demonstrate this.

There is no data on the low-FODMAP diet in people without IBS, so it is not advisable for the whole family, if one member needs to follow it.

Professor Peter Gibson, director of gastroenterology at Alfred and Monash University, Australia
The history of the low FODMAP diet

The effect of individual sugars and fibres on IBS symptoms have been known about for many years – lactose since 1965 (leading to lactose maldigestion), fructose since 1978 (leading to symptoms of malabsorption), polyols since 1966 (again leading to malabsorption), fructans since 1987 and GOS since 1969 (leading to fermentation / wind) - but the low FODMAP diet as a whole brings the various sugars together.

Underlying the FODMAPs concept are safety, measurement of food content, development of its dietary principles, demonstration of efficacy, educational methods, and worldwide implementation.

Dr Jacqueline Barrett, dietitian, Monash University, Australia<
How to institute the low FODMAP diet

It’s important to explain the mechanism of the diet to patients.

Barrett argued that lactose and fructose breath testing have ‘inappropriately become a major focus when implementing the low FODMAP diet’. Sorbitol and mannitol tests are also offered by some companies, but only a lactose breath test may be useful. The problems with breath testing are:
* poor reproducibility;
* false negatives;
* symptoms can occur regardless of absorptive capacity;
* it’s expensive;
* poor follow-up.

Negative results do not mean that a low-FODMAP diet may be irrelevant.

The level of FODMAP restriction should be adapted individually according to patients’ food preferences, medical history and circumstances. Avoid overwhelming the patient. Four-week follow-up is key. It is successful, but it has only been evaluated as a dietitian-taught diet (not self-administered).

Heidi M Staudacher, dietitian and researcher at King’s College London
How to use the low FODMAP diet safely

The impact on nutrient intake, the microbiome and quality of life must be considered. There is initial evidence that nutrient intake is maintained in the long-term, but more data is needed. An eye must be kept on iron and calcium intake.

Fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) are reduced by 50% on the low-FODMAP diet, and these are prebiotics. Reduction can effect the microbiome.

Robin Spiller, professor of gastroenterology, The University of Nottingham
How do FODMAPs work?

Eating often precipitates IBS symptoms, but not all FODMAPs have the same effect on the bowel.

Mechanisms include stimulation of colonic motility and sensitisation of visceral afferents.

FODMAPs’ mode of action varies with chemistry and microbiota:
* lactose / mannitol / fructose distend the small bowel (osmotic effects dominate)
* fructans / inulin and fructose increase gas and distend the colon (fermentation effects dominate)

Symptoms in IBS patients but not in healthy controls suggests visceral hypersensitivity is the key.

Dr Miranda Lomer, senior consultant dietitian for gastroenterology, Guys and St Thomas’ NHS Foundation Trust
Who should deliver the low FODMAP diet and what educational methods are optimal?

The short answer to the first part of the question is: dietitians! Healthy eating and good health habits should come first when treating IBS.

Low-FODMAP group education may also be beneficial: there is increased individual interaction, peer support and lower costs.

CK Yao, research dietitian,  Monash University, Australia
The value of breath hydrogen testing

There are issues with methodology in breath testing: sampling frequency, cut-off values to define malabsorption and dose of test sugar impact breath-testing outcomes. The dose of test sugar is unrealistic in reflecting dietary consumption – 35g of fructose would require the consumption of many pieces of fruit, and 50g lactose more than a carton of milk.

Breath test responses vary over time: 30% lose response on second fructose breath test. This great variety indicates they may be unreliable. Lactose is probably the only breath test of use for patients with functional bowel disorders. A single breath measurement gives little information about an individual’s intestinal physiology. The presence of malabsorption on breath testing is an inaccurate guide for predicting a true intolerance to individual FODMAPs – consider food challenges instead, once food symptom control is established.

Caroline Tuck, dietitian, Monash University, Australia
The challenge of the re-challenge and strategies to adapt the low FODMAP diet to the patient

The re-challenge process:
* There is no one-size-fits-all approach to food challenging
* Continue the low FODMAP diet while challenging
* One challenge at a time and monitor symptom response
* Challenge food over 3 days – but stop challenge if significant symptoms occur, and increase dose as tolerated
* Two-three day ‘washout’ between each challenge
* Encourage patients to keep notes.

Day 2, Tuesday 3rd November, 2015

Professor Peter Gibson, director of gastroenterology at Alfred and Monash University, Australia
Adapting the low FODMAP diet to special populations: inflammatory bowel disease

IBDs (mainly ulcerative colitis and Crohn’s disease) are rare (0.2%) while IBS is common (15%).

IBS-like symptoms are three times more likely to exist in quiescent IBD patients, where the diet may help. Lactose malabsorption is more common in IBD, and fructose and lactose malabsorption are very common in Crohn’s.

Gibson advises caution using low FODMAP in IBD as under-nutrition is common in this group and the effect on the microbiome must be considered. There is no evidence yet of an anti-inflammatory effect of the diet in IBD.

The diet should not be used when there is active disease or no problem to fix, but can be used when there are functional gut symptoms, high ileostomy output / unacceptably frequent ileal pouch emptying. It must be under dietetic supervision, especially if the patient is already malnourished.

Marina Iacovou, dietitian, Monash University
Adapting the low FODMAP diet to special populations: infants and children

Children may consume excess fruits or dairy which increases FODMAP load – but don’t forget a healthy balanced diet.

The low FODMAP diet in breastfeeding mothers may benefit infants with colic, but more studies are needed and underway.

The diet in children must be managed carefully and sensitively to avoid creating fear.

Dr Victoria Tan, University of Hong Kong
Adapting the low FODMAP diet to special populations: functional dyspepsia

FD is a common gastrointestinal disorder affecting 12-15% of the general population. In Asia-Pacific region it is 2-3 times more common than IBS. FD and IBS are similar – except there is belching in FD, with no change in bowel habit. There is evidence that in East Asia a proportion of patients with IBS may have been misdiagnosed with FD. The Chinese diet can be high FODMAP, but Asians consume far less rice than believed.

It is highly probable that the low FODMAP diet will benefit FD but there is no controlled evidence at present. Research on FODMAPs and FD, GERD and reflux are urgently needed.

Dr Jane Muir, head of translational nutrition science, dept of gastroenterology, Monash University
FODMAPs across the globe: FODMAP composition of Australian international foods and challenges of implementing a low FODMAP diet in the USA.

It takes two weeks in the Monash laboratory to analyse the FODMAP content of a food – it’s a long and expensive process.

As an example of the dedication of the Monash team: they grew collard greens (very popular in the US) to test, on the request of a FODMAP dietitian in America!

Patients who improve on gluten-free grains may be benefiting from lower FODMAP not lower gluten.

Higher FODMAP grains and cereals may be useful to increase prebiotic intake in coeliac patients.

FODMAP content varies widely internationally: white bread in Australia, USA and Norway are very different. The same gluten-free bread bought in two countries in different years was found to be low FODMAP in 2014 but high in 2015 (the first and second ingredients became the second and first ingredients respectively in the reformulation).

Spelt flakes and spelt pasta are still high in FODMAPs, but processing (for example spelt sourdough bread) reduces its FODMAP content.

Silken tofu is not low FODMAP - only firm tofu is.

Kate Scarlata, dietitian and low FODMAP educator
Challenges of implementing the diet in the USA

High fructose corn syrup in the USA contains excess fructose. It is added to ketchup, cereals, granola bars and other food products. There has been a greater than 1000% increase in its intake in the last 20 years in America. The consumption of total fructose increased by nearly 30% between 1970 and 2000, mostly due to HFCS.

Large fructose load is common with 3-4 servings of fruit in a smoothie.

Maltodextrin could be a source of fructans.

The trend towards reduced wheat intake in the US is due to low-carbohydrate diets. We need to dispel the myth that gluten-free is healthier. Other ingredients in gluten-free products are not always healthy.

Sourdough bread, especially spelt, has simple ingredients, low additives, and is low FODMAP – good for IBS.

Long working hours increase ‘eating out’ – may increase portion sizes and FODMAP intake, and may make compliance difficult.

Kevin Whelan, Professor of Dietetics, King’s College London
Prebiotics: the flip-side of FODMAPs

Bifidobacteria are probably important for gut health but these reduce on a low FODMAP diet. Prebiotics have potential benefits in maintaining diverse microbiota.

In IBS, there are limited clinical trials of prebiotics but benefits seem to be with specific prebiotics at lower doses.

In Crohn’s disease, a large trial has shown that there is no evidence of benefit of prebiotics during active disease. There may be more potential in maintenance.

Thanks to Patsy Catsos, Dara Morgan, Caroline Tuck, Sasha Watkins, Kate Scarlata, Heidi Staudacher, Kym Lang, Jaci Barrett, and especially to MONASH University for the tweets using hashtag #gastrodiet.

The event was sponsored by Nestlé Health Science and The Journal of Gastroenterology & Hepatology Foundation.

For more conference reports on all aspects of food sensitivity and food allergy, see here.

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