Fructans: What are They?

Ever heard of fructans? Fructans, not to be confused with fructose, are fermentable sugars that can cause GI distress in some people (emphasis on some). Maybe you’ve heard of them and thought yourself  “What the Fructan?!”… (Sorry, I had to make the joke).

So let’s talk about Fructans, what they are, why you might avoid them, and how to avoid them.

What are Fructans?

So what are exactly fructans? You’ve heard of probiotics and prebiotics (read more about probiotics with celiac disease here), and now this new term is being thrown around?

How are we supposed to keep up? Well, that’s why I am here! To help break down trending nutrition info into a more digestible form (I’ve never been on such a roll with puns in a blog post before!)!

And actually, that is essentially what fructans are, food to be digested by probiotics. Fructans are one of many sugars known as a FODMAP. FODMAPs are fermentable oligosaccharides, disaccharides, monosaccharides and polyols.

FODMAPs can be triggering for some people, and Fructans are one of the FODMAPs that may be monitored for intolerance. What’s important to know here is that FODMAP intolerances can improve and they are dose dependent.

Breaking Down Fructans Further...

To understand fructans, let me give you a basic rundown on the basics of probiotics and prebiotics. Probiotics are good bacteria that can be found in fermented foods, supplements, and in the bodies microbiome.

Probiotics are important for maintaining proper gut function, keeping the immune system healthy, and managing inflammation. As a part of the microbiome, their role is vast in keeping us healthy. So how do we keep them alive? We do so by feeding them Prebiotics!

Prebiotics are found in foods. Specifically, they are the dietary fibers found in food that serve as an energy source for good bacteria (probiotics). Prebiotics essentially feed probiotics.

Prebiotics are what feed probiotics and fructans are a category of prebiotics. Fructans are chains of fructose molecules that are broken down and used as fuel by good bacteria. This means fructans feed the good bacteria found in fermented foods and in our gut.

What are Fructans? Do you Need Them? Should you Avoid Them? - Tayler Silfverduk

What Foods are High in Fructans?

So fructans help feed the gut but they can also be triggering for some people, so what foods are high in fructans? Foods high in fructans include:

  • Agave
  • Asparagus
  • Bananas
  • Barley (already avoided on a GF diet)
  • Garlic
  • Onion
  • Jicama
  • Wheat (also already avoided on a GF diet)

It’s important to remember here that nutrition and diet are all about individualization. Our bodies process foods differently and have different needs. And weighing the benefits of these foods as gut nourishing foods while also acknowledging for some, they may trigger GI distress is important. And ultimately, do not cut any food out with out confirming with your doctor or dietitian that it’s truly necessary. Diverse diets are essential to health.

Of note: high-fructan foods that are fermented might be suitable when the non-fermented version isn’t. This is because the probiotics in the fermented foods have pre-digested (if you will) the fermentable sugars, thus making it easier on your digestive system to process.

This is why there is a myth that people on a gluten-free diet can tolerate sourdough. The sourdough is fermented and thus, the fructans in the wheat flour ferment and become more tolerable. However, what’s key here is the fructans are different from gluten.

And this where fructan intolerance can be mistaken for gluten intolerance. A lot of people who react to gluten products may actually just be having trouble digesting the fermentable sugars found in barley and wheat.

And I want to make it clear, fructan intolerance and gluten intolerance are different from celiac disease. Sourdough made from wheat is never safe for someone with celiac disease.

Now What?

You know what Fructans are, how they function, why you might avoid them… now what? If you’re concerned about your own fructan intolerance, discuss your concerns with your dietitian to assess if they are concern. Otherwise, go on about your day knowing these foods are nourishing your gut when you eat them.  (A reminder, if you need to follow a gluten-free diet, please don’t consume Barley or Wheat, they are not safe, even when fermented).

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