An introduction to Fructose Malabsorption from expert IBS dietitian Nick Dunn of Diet Solutions. For dietetic support with the low FODMAP process please contact Diet Solutions on 1300 422 498 or for further information go to www.dietsolutions.net.au
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. It is characterised by gastrointestinal symptoms that are not explained by other disorders. The most common symptoms include lower abdominal discomfort/pain, bloating, excessive wind, distension and/or an altered bowel habit (diarrhoea and/or constipation). It is important that other serious gastrointestinal diseases or other conditions are ruled out. This is why it's important to not 'self-diagnose' and if you are experiencing these types of symptoms, please seek medical advice before changing your diet.
What are the dietary triggers of IBS?
For many years, patients have related their symptoms to fatty foods, alcohol, gluten and caffeine. Most of the research investigating such triggers is unsubstantiated. Research of the past 15 years has focused on a large group of dietary sugars called FODMAPs. These sugars can be poorly absorbed in the small intestine and fermented by bacteria to produce gas. Current research strongly suggested that this group of sugars contribute to IBS symptoms.
What are FODMAPS?
Fermentable Oligo-saccharides, Di-saccharides, Mono-saccharides and Polyols
These sugars are poorly absorbed and can be found in a wide range of foods and include:
Fructose in excess of glucose
- Found in certain fruits, vegetables and honey
- The absorption of fructose in the small intestine relies on the activity of special 'sugar transporters'
- Most people absorb fructose, but around 30-40% of healthy individuals who suffer from IBS malabsorb excess fructose
- Found in milk and milk products such as yogurt and ice cream
- The absorption of lactose requires the sugar to be chopped in two by an enzyme call lactase. If you are deficient in this enzyme then you will malabsorb lactose.
Fructans and Galactans
- Fructans are found in wheat, rye, onions and garlic
- Galactans are found mostly in legumes
- Humans do not have the enzymes to break down fructans or GOS so all will be malabsorbed in the small intestine and bacteria will rapidly break them down
- A fructan and falactan restricted diet is always recommended in IBS.
Seek the advice of an experience dietitian.
The low FODMAP diet is not to be followed long terms as restriction of these food can contribute to poor bowel health long term.
Dietary restriction of these poorly absorbed FODMAP sugars is a specialised area of nutrition. It is vital that you seek guidance from a dietitian with experience in this area. There are many intricacies to undertaking a trial of this diet and the process is not as simple as avoiding a list of high FODMAP foods. The dietitian will also ensure that your diet remains balanced and nutritionally adequate whilst following the low FODMAP diet. It is generally recommended that a low FODMAP diet be trialled for a period of 2-6 weeks. Individuals should then be reviewed by a dietitian, who will advise which foods (and how much) can be reintroduced into the diet.