Are Polysaccharides High in FODMAP? A Comprehensive Guide

January 4, 2026 •

3 min read

While all polysaccharides are complex carbohydrates, not all of them are high in FODMAPs. A polysaccharide's FODMAP status depends on its specific type and how it is processed by the gut, which can greatly impact individuals with Irritable Bowel Syndrome (IBS). Understanding this distinction is crucial for navigating a low-FODMAP diet effectively.

Quick Summary

This guide explains why some polysaccharides, like fructans and galactans, are high-FODMAP while others, such as resistant starch in certain foods, can be low-FODMAP. It details how their fermentation in the gut affects symptoms and offers practical food lists for informed dietary choices.

Key Points

Polysaccharides vary in FODMAP content: Not all polysaccharides are high-FODMAP; some, like fructans and galactans, are, while others, like starches in rice, are not.
High-FODMAP polysaccharides are oligosaccharides: This group includes fructans from wheat and garlic, and galactans (GOS) from legumes, which are poorly absorbed and highly fermentable.
Slow fermentation is key: Resistant starch is a polysaccharide that ferments slowly, producing less gas and often causing fewer symptoms than high-FODMAPs.
Canned legumes can be low-FODMAP: Rinsing canned lentils and chickpeas removes much of the high-FODMAP GOS, making them tolerable in small portions.
Soluble fiber is generally better tolerated: Low-FODMAP soluble fibers, such as psyllium husk, can be beneficial for IBS symptoms, while high-FODMAP soluble fibers like inulin are best avoided.
Low-FODMAP grains contain polysaccharides: Grains like oats, rice, and quinoa are safe sources of complex carbohydrates on a low-FODMAP diet.
Portion control is critical: Even low-FODMAP foods can trigger symptoms in large quantities, so following recommended serving sizes is important.
Consult a professional for personalized advice: Working with a FODMAP-trained dietitian is recommended to navigate the complexities of this diet and ensure nutritional balance.

Understanding the Complex Relationship Between Polysaccharides and FODMAPs

Polysaccharides are long chains of sugar molecules, and the term itself encompasses a vast range of carbohydrates, from starches that we can digest easily to certain fibers that resist digestion. The key question for those following a low-FODMAP diet is not whether a food is a polysaccharide, but whether it contains specific types of polysaccharides that are poorly absorbed and rapidly fermented in the gut. For example, the oligosaccharide group of FODMAPs consists of fructans and galactans, which are both indigestible polysaccharides that can trigger symptoms like bloating and pain in sensitive individuals.

What Makes Some Polysaccharides High-FODMAP?

High-FODMAP polysaccharides, known as oligosaccharides, are short-chain carbohydrates found in foods like wheat, garlic, onions, and legumes. For most people, these act as beneficial prebiotics, feeding gut bacteria. However, in people with IBS, the rapid fermentation of these compounds in the large intestine produces gas, leading to symptoms such as bloating, abdominal pain, and flatulence. Another contributing factor is that FODMAPs draw extra water into the intestine, which can affect bowel motility.

Can Polysaccharides Be Low-FODMAP?

Yes, many polysaccharides can be part of a low-FODMAP diet. The difference lies in their specific structure and how they are broken down in the body. For instance, while fructans in wheat are high-FODMAP, the starches in rice and potatoes are generally well-tolerated. The concept of resistant starch further illustrates this. Resistant starch is a type of polysaccharide that escapes digestion in the small intestine but is slowly fermented in the large intestine, leading to a more gradual gas release that is often better tolerated than the rapid fermentation of FODMAPs. Cooking and cooling starchy foods like potatoes and rice can also increase their resistant starch content.

Comparing High-FODMAP Polysaccharides vs. Low-FODMAP Polysaccharides


Feature	High-FODMAP Polysaccharides (Oligosaccharides)	Low-FODMAP Polysaccharides (Select Starches/Fibers)
Types	Fructans, Galactans (GOS)	Resistant Starch (RS2, RS3), some Soluble Fibers
Digestion	Poorly absorbed in the small intestine	Largely digested in the small intestine or slowly fermented in the large intestine
Fermentation Rate	Rapid	Slow or minimal
Gas Production	High, can cause bloating and pain	Gradual, often better tolerated
Common Sources	Wheat, rye, onions, garlic, beans, lentils	Rice, oats, potatoes (cooked/cooled), unripe bananas
Effect on IBS	Often triggers symptoms	Generally well-tolerated, may improve gut health

Navigating Polysaccharides on a Low-FODMAP Diet

For people managing IBS, focusing on the type of polysaccharide rather than the general category of complex carbohydrates is essential. A diet rich in low-FODMAP fibers can help support gut health without triggering symptoms. Key strategies include:

Prioritize Low-FODMAP Sources: Incorporate foods like rice, quinoa, and oats, which contain polysaccharides but are generally low in FODMAPs.
Control Portion Sizes: Even low-FODMAP foods can become high-FODMAP in large servings. The Monash University FODMAP Diet app is a valuable resource for checking specific serving sizes.
Consider Cooking Methods: The resistant starch content in potatoes and rice increases when cooked and then cooled, offering a type of polysaccharide that is often better tolerated by those with IBS.
Include Soluble Fiber: Some soluble fibers, like psyllium husk, are low-FODMAP and can help regulate bowel movements. However, high-FODMAP fibers like inulin should be avoided.
Don't Fear All Legumes: Canned lentils and chickpeas can be low-FODMAP in specific portion sizes (e.g., ¼ cup canned lentils) if rinsed well, as the high-FODMAP galactans (GOS) leach out into the canning liquid.

The Importance of Specificity

For someone with IBS, understanding the specific types of fermentable carbohydrates within foods is far more useful than simply categorizing them as 'polysaccharides'. The presence of fructans in wheat, for instance, is the issue for many, not the broader 'complex carbohydrate' label. By focusing on tested, low-FODMAP sources of carbohydrates and dietary fiber, it is possible to maintain a nutritionally balanced diet that minimizes digestive distress.

Conclusion

To answer the question, "Are polysaccharides high in FODMAP?", the answer is: it depends. The broad category of polysaccharides includes some high-FODMAP types like fructans and galactans, which are known triggers for IBS symptoms due to rapid fermentation. However, it also includes many low-FODMAP options, such as certain starches and fibers found in foods like rice, potatoes, and oats. The key is to distinguish between these types and to manage serving sizes, preferably with guidance from a FODMAP-trained dietitian. By doing so, individuals can find a balanced diet that supports their gut health without causing unnecessary discomfort.

Visit the official Monash University FODMAP Diet website for scientifically-backed information

Frequently Asked Questions

A polysaccharide is a broad category of complex carbohydrates, which includes starches and fibers. A FODMAP is a specific type of short-chain carbohydrate, and some high-FODMAPs, such as fructans and galactans, are indeed polysaccharides. However, many other polysaccharides, like those in rice, are not FODMAPs.

No, you do not need to avoid all complex carbohydrates. Only specific fermentable ones, classified as FODMAPs, are restricted on a low-FODMAP diet. Many complex carbohydrates, such as starches in rice and potatoes, are low-FODMAP and well-tolerated.

No, dietary fibers can be either low or high in FODMAPs. Some soluble fibers, like psyllium husk, are low-FODMAP, while others, like inulin and fructans, are high-FODMAP.

While resistant starch is often better tolerated than high-FODMAPs because it ferments slowly, high intakes can still cause discomfort in very sensitive individuals. It is best to introduce it gradually and monitor your body's response.

Wheat and rye are restricted primarily because they contain high levels of fructans, a type of high-FODMAP polysaccharide. The issue is the fructan content, not necessarily the gluten, though many gluten-free products are also low-FODMAP.

To increase fiber intake, focus on low-FODMAP sources like oats, rice, quinoa, carrots, and potatoes. You can also use low-FODMAP fiber supplements, such as psyllium husk, if recommended by a dietitian.

Most modified food starches are considered low-risk and are likely low-FODMAP, as they are typically used in small quantities. However, if you are highly sensitive, checking with a dietitian or a certified app is the safest approach.