What are FODMAPs?

Everything you need to know about FODMAPs: understand and relieve your digestion

Introduction: why is everyone talking about FODMAPs?

Bloating, gas, chronic abdominal pain… If these symptoms sound familiar, you have probably already looked for an answer on your plate. Among the most frequently mentioned culprits, one term keeps coming up: FODMAPs. But what exactly are they?
FODMAP is an acronym for short-chain carbohydrates that are often poorly absorbed in the small intestine. Because they are not properly assimilated, they continue through the gut to the colon, where they are fermented by the bacteria of the gut microbiota. These carbohydrates act as genuine prebiotics, helping to feed the gut microbiota and maintain its balance. However, their fermentation produces gas that can lead to bloating and flatulence.
Generally well tolerated by most people, FODMAPs can nonetheless cause various digestive issues in some individuals. They are notably involved in Irritable Bowel Syndrome (IBS), which affects nearly 15% of the world’s population (Source: Monash University).
At Nahibu, we analyse your gut microbiota using shotgun metagenomic sequencing to understand how your flora digests these sugars.

The goal? To offer you personalised nutrition so you can regain lasting gut comfort, without unnecessary frustration.

What does FODMAP mean? Breaking down the acronym

To better understand what lies behind this complex name, it helps to introduce the broad family of carbohydrates. They fall into three categories, depending on their chemical composition and the number of sugar units they contain:

• Simple sugars: from 1 unit (monosaccharides) to 2 units (disaccharides),
• Oligosaccharides: from 3 to 9 units,
• Polysaccharides: more than 10 units.

Some carbohydrates are perfectly digested by our body, others are not and therefore fall into the FODMAP category:

F for FODMAPs: fermentation

The F stands for “Fermentable”. This is a biochemical reaction that releases energy from a substrate and produces by-products thanks to microbial enzymes. Fermentation essentially transforms certain molecules into other molecules. There are different types of fermentation, for example:

• Lactic: lactic acid forms from glucose.
• Propionic: acids and gases also form from glucose.
• Alcoholic: ethanol and carbon dioxide are produced from glucose.

The fermentation of undigested carbohydrates is thought to be partly responsible for bloating. The volume of the abdomen can increase by 3 to 4 centimetres over an 8-hour period. To address bloating and other digestive discomfort, a low-FODMAP diet is currently the most effective approach for people with irritable bowel syndrome.

O for FODMAPs: oligosaccharides

They belong to the carbohydrate family, more commonly known as “sugars”, which are the body’s main source of energy. Oligosaccharides result from the combination of several smaller sugars arranged in chains, branched or not. Their prefix “oligo-” means we are dealing with medium-sized carbohydrates. Among FODMAPs, two families of oligosaccharides stand out: fructans (which include Fructo-Oligo-Saccharides (FOS) and inulin) and Galacto-Oligo-Saccharides (GOS).

Oligosaccharides are present in many vegetables and cereals. Fructans are found mainly in wheat, rye, barley, garlic, onions, cabbage, Jerusalem artichokes, globe artichokes, asparagus, beetroot, leeks, chocolate and chicory, while GOS are mainly present in artichoke and pulses (such as chickpeas, kidney beans, lentils, cashews, pistachios and seaweed).

Because oligosaccharides are still essential to the health of our gut microbiota (and therefore to our own) and because the foods that contain them add diversity to our diet, it is best not to completely eliminate sources of oligosaccharides, at least in the long term. To limit your intake, however, you can use a few tips:

• Choose cereal products (bread, pasta, rice, etc.) made from refined grains (oligosaccharides are mainly found in the husk, which is preserved in wholegrain cereals),
• Prefer canned, drained pulses, which contain fewer FODMAPs than those you cook yourself,
• Let your artichoke rest for 1 or 2 days, then cook it well to reduce its oligosaccharide content,
• Use garlic and onion as seasonings to flavour an oil, marinade or stock, or remove them from your dish before eating.

D for FODMAPs: disaccharides

In our diet, disaccharides include:

• Sucrose, which is table sugar (a combination of glucose and fructose).
• Maltose, the combination of two glucose units.
• Lactose, a combination of glucose and galactose.

Lactose is the one that causes problems for people with irritable bowel syndrome. In children, lactose is digested in the small intestine thanks to lactase (an enzyme), but the production of this enzyme decreases considerably over the years. Insufficient lactase production no longer breaks lactose down into glucose and galactose for intestinal absorption. Lactose can therefore no longer be digested, which is known as lactose intolerance. Note that this is not an allergy to cow’s milk protein, which involves an immune reaction.

Rest assured: lactose intolerance does not mean saying goodbye to dairy. Some products have a low lactose content and may potentially be eaten, depending on individual tolerance. You can try certain hard cheeses (cheddar, parmesan, gouda), blue cheeses (blue, roquefort), camembert and mozzarella. Good to know for fans: butter is low in FODMAPs.

Finally, plant-based drinks can be a real alternative to cow’s, sheep’s or goat’s milk. Soya, oat, almond, rice or quinoa drinks can be an option, and they now come in many forms: yoghurts, dessert creams, ice creams, and more.

M for FODMAPs: monosaccharides

These are simple sugars, made of a single unit (“mono-”) and not bound to other compounds. They do not need to be broken down by digestive enzymes and can be absorbed as they are. But one of these monosaccharides, fructose, can still be a problem. Fructose is a sugar found mainly in fruit (apples, pears, melons, peaches, raspberries, pineapple) but also in vegetables (tomatoes, peppers), products derived from them (jams, compotes and sauces, dried and candied fruit) and honey. Since it is excess fructose that causes digestive problems, fruit and vegetables containing limited amounts of fructose relative to glucose can be eaten even with IBS.

Fruit and vegetables are essential in our diet because they provide dietary fibre, vitamins and minerals, and they add colour and texture to our plates. So in the case of fructose sensitivity, there is no question of banning all fruit and vegetables, but you should try to choose those that are tolerated. Among the foods most likely to contain excess fructose are apples (and all the compotes and purées that contain them), pears, mangoes, grapes and raisins, melon, red fruits (strawberries, redcurrant) and, among vegetables, shallots, red pepper and processed tomatoes (sun-dried tomatoes, tomato paste).

On the other hand, you can more easily eat citrus fruits (lemon, grapefruit, clementine, orange), plums (mirabelles, greengages), some red fruits (blackberries, blueberries), peaches and nectarines, and rhubarb. Finally, fruit canned in syrup generally has a better balance between fructose and glucose, which makes it suitable for a low-FODMAP diet.

P for FODMAPs: polyols

Polyols, or sugar alcohols, are carbohydrates produced by the chemical transformation of simple sugars. Polyols are very often used as sweeteners because they give food a sweet taste while limiting energy intake. They are therefore very common in so-called “light” or sugar-free products. To identify them, look in the ingredient list for additives starting with E: E420 (sorbitol), E421 (mannitol), E953 (isomalt), E955 (sucralose), E965 (maltitol), E966 (lactitol), E967 (xylitol), E968 (erythritol). Polyols can also be found naturally in some foods such as dried fruit, pears or plums, which are rich in sorbitol; xylitol in cauliflower, strawberries and raspberries; and mannitol in mushrooms or seaweed.

The absorption rate of polyols varies, and intestinal malabsorption increases their concentration in the colon. That is where the trouble begins. This malabsorption promotes colonic fermentation, which explains the pain associated with IBS. The most common symptoms? Bloating, flatulence and diarrhoea. Don’t panic: many foods can still be eaten despite a sensitivity to polyols. You can, for example, enjoy plenty of citrus fruits (lemon, mandarin, grapefruit), exotic fruits (passion fruit, pineapple, papaya), grapes, melon (in season), and so on. A sensitivity to polyols hardly limits your vegetables, apart from cabbage and button mushrooms. Finally, avoid foods labelled “0%”, “sugar-free” or “low-carb”. If you have a sweet tooth, choose unsweetened products, sucrose-based chewing gum or mints.

We know that’s a lot of information, but this summary is a good basis for understanding what we mean by FODMAPs.

Why do these carbohydrates make your stomach swell?

The presence of poorly digested FODMAPs in the intestinal lumen attracts water by an osmotic effect, which increases intestinal volume. When they reach the colon, they are rapidly fermented by the microbiota, producing gas. The build-up of water and gas distends the intestine, causing bloating, a swollen stomach and sometimes abdominal pain, particularly in people with intestinal hypersensitivity.

FODMAP list: where do they hide?

It is essential to identify the sources to better manage your gut health. Here is a non-exhaustive list of foods rich in FODMAPs:

Oligosaccharides: fructans and GOS

Where can they be found?

Fructans: cereals (wheat, barley, rye), condiments (garlic, onions, shallots), vegetables (leeks, artichokes, asparagus, cabbage), fruit (mangoes, nectarines, peaches, grapefruit, etc.)
GOS: pulses (chickpeas, lentils, beans), soya-based products, nuts (cashews, pistachios, etc.)
Nahibu tip: these foods are excellent prebiotics. Don’t eliminate them for good! Flavour your dishes with garlic infused in oil (FODMAPs do not pass into fat) or choose well-rinsed canned pulses.

Disaccharides: lactose

The problem: over time, a lack of lactase (a digestive enzyme) prevents the absorption of lactose, leading to lactose intolerance. It is found in animal dairy products and fresh and soft cheeses.
Alternatives: hard cheeses (parmesan, cheddar), plant-based drinks (almond, rice) and butter (naturally very low in lactose).

Monosaccharides: fructose

• Limit your intake of apples, pears, mangoes, honey, agave syrup, fruit juices and dried fruit.
• Favour citrus fruits, mirabelle plums (moderate FODMAP), clementines and slightly unripe bananas, for example.

Polyols: the “hidden” sugars

• Sorbitol: apples, pears, cherries, peaches, prunes, dried fruit, etc.
• Mannitol: fresh mushrooms, cauliflower, celery, etc.

Tip: other polyols (xylitol, maltitol, isomalt, etc.) are also used as additives, so check the labels of processed products.

FAQ: your questions about FODMAPs

Are FODMAPs bad for you?
No. FODMAPs are not harmful in themselves: they act as prebiotics that nourish the gut microbiota. They only cause discomfort in sensitive people, particularly those with IBS, because of the gas produced during fermentation.

Should I follow a low-FODMAP diet for life?
No. A low-FODMAP diet is generally used as a temporary elimination phase followed by gradual reintroduction, to identify the specific foods you tolerate. Cutting out all FODMAPs permanently can impoverish your microbiota, so it is best done with professional guidance.

How can Nahibu help?
Nahibu analyses your gut microbiota using shotgun metagenomic sequencing to understand how your flora ferments these sugars, and provides personalised nutritional recommendations to help you regain lasting gut comfort.