FODMAP Explained: “M” Stands for Monosaccharides
Welcome back to my “FODMAP Explained” Series! This is a set of articles dedicated to explaining the acronym FODMAP and giving practical tips to avoid symptoms while including as wide a variety of foods as possible.
The M in FODMAP stands for Monosaccharide (or single-sugar unit) and the sugar of concern here is fructose. Fructose is the main sugar present in fruit but it is also found in sucrose or table sugar, where it pairs up with glucose (glucose + fructose = sucrose).
Why should people with IBS be concerned about fructose? Fructose is slowly absorbed and, when excess fructose is lingering in the small intestine, it attracts water and leads to distension. The belly literally expands and can feel and look like what many IBS sufferers describe as a “pregnant belly”. In addition, it is poorly absorbed, and the unabsorbed excess fructose travels to the large intestine where our friendly bacteria ferment it, triggering gas production and bloating.
Fructose in the low FODMAP Diet
Not all fruits nor table sugar are excluded from the elimination phase of the low FODMAP diet. Why? Because, as long as there is an equal amount of fructose and glucose in a fruit (for example, strawberries), fructose is absorbed efficiently.
When there is an excess of fructose (compared to glucose) in a fruit (as in mango) or when you consume too much fructose - from large amounts of fruits or sugar - that’s when the intestinal tract cannot handle the absorption of fructose efficiently and symptoms appear.
Bottom line: what can you eat?
If you have IBS and have undertaken the low FODMAP diet to help you manage your symptoms, you need to pay attention to both the type and the amount of fructose you ingest (either as a fruit or in the form of sugar). Here are a few tips:
1. Choose low-FODMAP fruits: these have equal amounts of fructose and glucose. Some examples are strawberries, blueberries, cantaloupe, oranges and papaya. See my recipe for Balsamic Strawberries below.
2. Eat them in low FODMAP serving sizes and limit them to one serving per meal or snack (check out the Monash University FODMAP Diet App for appropriate serving sizes).
3. Avoid high-FODMAP fruits: these have more fructose than glucose and even small amounts can lead to symptoms. Some examples are mango, apple, some dried fruit but also asparagus and snap peas (I know, these are vegetables but they do contain excess fructose – ever wondered why snap peas are so sweet? Now you know).
4. Avoid honey, agave and high-fructose corn syrup, as these sweeteners are mostly composed of fructose (and little glucose).
5. Keep the portion of sugar and anything made with sugar – cookies, brownies, etc. – small: 1-3 teaspoons of sugar in a beverage, or about that much sugar per serving of a baked product/dessert per meal or snack are well tolerated by most people with IBS.
Finally, you need to follow these rules only during the elimination phase of the diet. If you pass the fructose challenge during the re-challenge phase, you can expand the amounts and types of fruit you can eat (everyone is different in their tolerance and you will need to find out your own threshold for fructose). If you find that fructose is a trigger FODMAP for you, keep following these tips but try and re-challenge fructose every 3-6 months. IBS symptoms come and go and change over-time, and you may find you can better tolerate fructose later on.
¼ cup (60 ml) Italian balsamic vinegar
2 teaspoons (10 ml) maple syrup
16 oz (450 g) strawberries
1. Combine the balsamic vinegar and maple syrup in a small, heavy-bottomed saucepan, bring to a boil, reduce the heat to low, and simmer gently until the vinegar is reduced to about 3 tablespoons, 3-5 minutes. Let cool.
2. Combine the strawberries and syrup and toss. Let stand for 30 minutes for the strawberries to marinate, stirring occasionally, before serving.
Yield: 4-6 servings
Chef’s note: Use this as a dessert on its own or as a topping for lactose-free vanilla ice-cream or plain lactose-free yogurt.
Storage: Store in an airtight container in the refrigerator for up to 2 days.
Author: Antonella Dewell, Registered Dietitian Nutritionist & Natural Chef