FODMAPs are a natural part of the good carb foods most of us need to eat more of – fruit; vegetables; dried beans, chickpeas, lentils; and whole grains. Here’s what FODMAPs (it’s an acronym) are and where you’ll find them plus tips on choosing low FODMAP carbs that will help you up your fibre intake if you have diagnosed IBS.
The F is for fermentable, the process through which friendly bacteria in the large intestine such as Ruminococcus gnavus break down the undigested parts of food such as soluble fibre in dried beans to produce short chain fatty acids like butyrate which provide nutrition for the cells that line our gut. Gas (hydrogen, methane, and carbon dioxide) is simply a by-product of the “fermenting”.
The O is for oligosaccharides – the fructo-oligosaccharides found naturally in fruits and vegetables such as asparagus, bananas, chicory root, garlic, Jerusalem artichokes, leeks, legumes, onions and wheat; and in wholegrain foods, especially rye and galacto-oligosaccharides in dried beans, chickpeas and lentils. They are actually a form of dietary fibre and they play a role as prebiotics, the non-digestible components of plant foods that promote good gut health by feeding the friendly bacteria (probiotics) in the large intestine (bowel). Inulin is one you will increasingly see on food labels as manufacturers add it to products to boost fibre content and reduce added sugars.
The D is for disaccharide. In this case, lactose, the primary carbohydrate in all mammals’ milk—cow, goat, sheep, buffalo, camel, and human and in the soft cheeses and yoghurt made from milk. Lactose needs to be broken down into its component sugars, glucose and galactose, before the body can use it. Lactase, a lactose-breaking, genetically controlled enzyme located in the small intestine, does this for us. Until we are three or four years of age, most (35 percent) of us have sufficient lactase to digest lactose. After this, lactase production virtually grinds to halt in many (65 per cent) people (as well as in animals, including dogs, cats, rats, mice, etc.).
The M is for monosaccharide. In this case fructose, the natural sugar found in fruit, which can be a problem when consumed in excess of glucose. Research shows when we consume equal amounts of glucose and fructose together (i.e., 50 percent fructose/50 percent glucose, as in sucrose or table sugar), there is no evidence of malabsorption in most people. But consuming fructose on its own is a different story and lots of people have fructose malabsorption. Some people can absorb less than 15 grams of fructose (in solution – water), others have trouble with 30 to 40 grams. Most of us will suffer from flatulence and diarrhea consuming 50 grams or more of pure fructose.
The P is for polyols, the sugar alcohols (erythritol, isomalt, lactitol, maltitol, mannitol, sorbitol, and xylitol) found naturally in many fruits and vegetables. They have been used as sugar substitutes in foods and drinks for many years as they provide fewer calories than regular table sugars and because the body treats them as dietary fibre, they have less effect on blood glucose levels. The downside: they can have a dire laxative effect. The upside: they are “tooth friendly”.
Irritable bowel syndrome and FODMAPs
FODMAPs somehow got hitched to the popular “free-from” diet bandwagon when research found that for many people (but not everyone) cutting back on foods rich in FODMAPs may improve common IBS symptoms – bloating and distension, excess wind, abdominal pain and altered bowel habits (diarrhoea and/or constipation).
If you suffer these distressing symptoms, please don’t self-diagnose and immediately rush out and buy a low FODMAP diet book because a friend told you it worked for her and she feels so much better. Please see your doctor first and get a clear diagnosis as to the cause of your symptoms – these very same symptoms can also be seen in other gastrointestinal diseases and what you may really need is prompt medical attention not simply a change of diet.
If you do have IBS, you can trial a low-FODMAP diet for 6 to 8 weeks with the help of a registered (accredited) dietitian (they’ll have RD or APD after their name) to see if your symptoms decrease or go away completely. If they do, your dietitian can then help you with a systematic reintroduction of FODMAP-containing foods to determine which kinds of carbohydrates are causing your symptoms (everyone is different) and how much your system can tolerate before any symptoms recur.
Strict low-fodmap diets are not designed to be consumed for long periods of time because they eliminate so many healthy foods. They are simply for diagnostic purposes. The end goal is to ensure that you enjoy a healthy diet with as wide a variety of foods as possible and without distressing gut symptoms.
Remember, changing your diet can change your gut bacteria – quite rapidly. No one knows the long-term effects of that on your health (and weight).
LOW-FODMAP FOOD TIPS
The good carbs in the following tables are all part of a healthy, low FODMAP diet. We have included the fibre count to help you may sure you get your 30 grams a day.
Make sure you eat plenty of green veg such as alfalfa, bamboo shoots, bean shoots, bok choy, broccoli, celery, choy sum, cucumber, green beans, lettuce (butter, iceberg), silverbeet (Swiss chard), spinach, spring onion (green part only) and zucchini (courgettes).
*Note that the GI of rice can range from low (47) to very high (98) depending on variety. Check the database at www.glycemicindex.com.