All about the low-FODMAP diet

All about the low-FODMAP diet

The low-FODMAP diet is one of the latest diets to have emerged and is gaining serious traction. Unlike the countless other diets which pop up every year, low-FODMAP is a medical-exclusion diet for sufferers of Irritable Bowel Syndrome (IBS).

FODMAPs are Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols: oligosaccharides are a component of fibre found mainly in plants (cereal grains, vegetables, legumes and some fruits); disaccharides are two monosaccharides linked together (sucrose, lactose); monosaccharides are the basic building blocks of carbohydrates, the simple sugars of which glucose and fructose are the most common (sweeteners, sugary fruits, dairy products); and polyols are sugar alcohols found in sweeteners and some fruits (sorbitol, mannitol, xylitol).

FODMAPs are everywhere: in milk, cheese, apples, pears, watermelon, blackberries, artichokes, broccoli, cauliflower, mushrooms, sweetcorn, asparagus, wheat, barley, rye, beans, hummus, soymilk, chocolate, garlic, onions, shallots, ketchup, honey, agave, sugar, camomile tea, rum, champagne, sherry and port.

FODMAPs are a group of short-chain carbohydrates present in many foods—particularly fruit and vegetables—and have been found to be poorly absorbed within the small intestine. Once ingested, some FODMAPs are not absorbed and increase the amount of water present. They pass along the gut to the large intestine, where they linger and are fermented by the billions of bacteria present there. This fermentation may result in gas production and symptoms such as wind and bloating. This occurs to some degree in all people regardless of whether they have IBS as nobody can break FODMAPs down completely. But in IBS, gut symptoms are induced more readily because of the way the muscles of the bowel respond to the distension and the hypersensitivity to changes in the gut environment and interactions with the immune and nervous systems.

IBS is a common functional gastrointestinal disorder affecting one in seven adults and has no abnormal pathology. Symptoms including lower abdominal pain and discomfort, swelling and bloating, flatulence, distension and altered bowel habits (from diarrhoea to constipation) can be accompanied by a lack of energy, nausea, backache and bladder problems. IBS can have a significant impact on a person’s life and have a deep psychological impact, including depression and anxiety. More prevalent in women, IBS is common around the world.

Prof Peter Gibson at Monash University in Melbourne first provided evidence that following a low-FODMAP diet improves IBS symptoms; of all those who took part in trials, over 70 percent reported a distinct improvement in their symptoms. The diet is complicated and involves three stages.

Stage 1: elimination

During this stage, sufferers completely eliminate all FODMAPs for six to eight weeks to identify whether symptoms will actually respond to a low-FODMAP diet. This is the tricky bit. FODMAPs are present in many foods, making mealtimes an organisational and culinary nightmare. But stick with it: if you are intolerant to a FODMAP, you should see improvements to your symptoms within a couple of weeks of this stage.

Stage 2: reintroduction

At this point, you start reintroducing each separate group of high-FODMAP foods separately. Each group is introduced for a week or so to assess whether it’s that group triggering your symptoms. Sometimes, sufferers will react to some foods within a group and not others—it depends how many FODMAPs are present within each food. It can be surprisingly tricky to reintroduce foods here as you need to eat them in as natural a way as possible: i.e. not by themselves but with other foods as close to how you would have them in a normal mealtime situation as possible. This can be pretty prescriptive and make meals feel too complicated.

Stage 3: personalisation

This is the long-term aim of the low-FODMAP diet. Once you’ve ascertained which foods cause symptoms and which don’t, you can make your diet as normal as possible—you only need to continue eliminating the problematic FODMAPs.

FODMAPs are present in many foods—eliminating many could lead to nutritional deficiencies as the vitamins and minerals in the fruits and vegetables are also avoided. Some high-FODMAP foods, such as onion and garlic, are staple foods and present in many recipes. While you could just take these out completely, it isn’t always possible to cook from scratch and eating on-the-go or in restaurants can be very difficult.

Luckily, there are very handy apps available to help you follow the low-FODMAP diet. The Monash University app is the original, and there is also one created by Food Maestro in partnership with Kings College London. You can absolutely give the diet a go if you’re suffering IBS symptoms, but as it’s so complicated, we’d recommend following it with a registered dietitian to ensure you follow a healthy, balanced diet and can get suitable low-FODMAP alternatives. There are plenty of foods you can eat on a low-FODMAP diet (strawberries, blueberries, spinach, kale, lettuce, tomatoes, rice, cornmeal, quinoa, maple syrup, dark chocolate, tofu, chickpeas, lentils, chives, herbs, ginger, beer, wine, gin, vodka, whiskey, coffee) and it’s important to remember you likely won’t need to eliminate all FODMAPs from your diet.

With all the research going on in our guts, the prognosis for IBS sufferers looks better and better. For now, give the low-FODMAP diet a go: start with taking out garlic and onion and see if that makes a difference.