**blog written by SBF dietician Peita Hynes BAppSc (HMS) hons. BHlth Sc (Nutr & Diet) hons
Bloating, abdominal pain, wind, constipation, diarrhoea or irritable bowel syndrome (IBS) affect approximately 1 in 7 Australian adults.
Recent research from Monash University has provided the first evidence that a low FODMAP diet improves IBS symptoms!!! So what is a FODMAP diet?
FODMAP is an acronym for:
- Oligosaccharides ( For example, Fructans and Galacto-oligosaccharides (GOS))
- Disaccharides (For example, Lactose)
- Monosaccharides (For example, excess Fructose)
- Polyols (eg. Sorbitol, Mannitol, Maltitol, Xylitol and Isomalt)
These are all scientific names for molecules that are found in food and that are poorly absorbed by some people. To understand it a bit better, it helps to understand what the small and large intestine do.
The small intestine breaks down and absorbs nutrients from food.
The large intestine absorbs water and prepares undigested food for removal from the body as faeces.
When food is poorly absorbed in the small intestine, it continues the journey and arrives at the large intestine. This poorly absorbed food then acts as a food for the bacteria that live in your gut. Bacteria digest and ferment these FODMAPS molecules which results in the production of gases including hydrogen and methane. This gives symptoms of abdominal bloating, wind, changes in bowel habits, pain and other gastro-intestinal symptoms. When the FODMAPS arrive at the large bowel, the malabsorption can also have an osmotic effect, which contributes to diarrhoea in some people.
Below is a summary of common FODMAPS foods
Foods with excess fructose:
- Fruits that contain more fructose than glucose: apples, pears, mangoes, watermelon
- High fructose corn syrup
Foods with excess fructans:
- Artichokes, asparagus, beetroot, lettuce
- Chicory, radicchio
- Garlic, leek, onion, shallots
- Pasta, bread, cereals where wheat is a major ingredient
- Rye, barley
Foods containing lactose:
- Milk, condensed milk, evaporated milk, milk powder
- Ice cream, custard, dairy desserts
- Soft unripened cheeses e.g. ricotta, cottage cheese, cream cheese
- Legume beans eg baked beans, kidney beans, borlotti beans
- Lentils, chickpeas
- Apples, apricots, avocado, cherries, nectarines, plums, lychees
- Mushrooms, cauliflower
- Sorbitol (420) mannitol (421) xylitol (967) isomalt (953)
Interestingly, our gut lacks enzymes to break down fructans and “GOS” in the small intestine, and they ferment in the colon (so certain amounts will always cause symptoms in everyone). This is why beans are known as the food that causes wind! However, people with IBS will experience symptoms with a smaller amount than those with IBS.
Those who suffer from fructose malabsorption do not need to avoid all fruits and foods that contain fructose.
It’s usually only a problem when excess fructose is present. Eg the fruit listed above.
30-40% of healthy individuals malabsorb excess fructose.
People with lactose intolerance can usually still manage small amounts of lactose or can choose lactose free products.
Lactose is naturally found in cow, sheep and goat milks. To digest lactose, our body uses lactase. Some individuals do not produce enough lactase to digest lactose and this can result in wind, bloated and loose bowel movements.
Before you go changing your diet, it is important to speak to a health professional and get advice from your doctor. Breath testing can identify if an individual absorbs fructose, lactose and sorbitol but is not specifically required. Trialling a low FODMAP diet and monitoring your symptoms may help determine whether FODMAPs influence your IBS symptoms.
Shepard, S and Gaskell, S. (2016). The Low FODMAPS Diet. Sports Dietitians Australia: https://www.sportsdietitians.com.au/factsheets/diets-intolerances/the-low-fodmaps-diet/
Monash University (2010). The Monash University Low FODMAP Diet booklet. (Edition 4). Department of Gastroenterology, Clinical Sciences School, Monash University, Melbourne, Victoria.