What the Fric are Fructans?

I’m being a little bit crafty with my terminology but honestly, I’d never heard of a fructan before the low FODMAP diet. I’m sure you are thinking the same thing too.

This article is for you if:

  • you’ve never heard of a fructan before or,
  • you know that fructans are found in garlic, onions, bread, and wheat and you can’t imagine living without them or,
  • the thought limiting fructans stops you from starting the low FODMAP diet

What are fructans and why do they cause digestive problems?

Fructans are oligosaccharides or the “O” in FODMAP. For the science enthusiasts or if you want to rewind to high school chemistry, fructans are chains of fructose molecules joined together with a glucose at the end. In order to breakdown fructans, our body must break the bonds between the fructose molecules. However, no one does this very well whether you have IBS or not. Only about 5-15% of fructans are digested in the small intestine and the rest reach the colon where they are naturally fermented.  Since fructans are small, they ferment very rapidly in the colon.  Among people without IBS, this simply causes a little extra gas. Among people with IBS, they may experience severe bloating, discomfort, pain and altered bowel movements. I suspect this may sound familiar.

Where are fructans found?

Fructans are found in some of our favourite foods like wheat, garlic, onions, artichoke, and asparagus (not a comprehensive list). If this makes you want to stop reading right now, DON’T! There are many low FODMAP alternatives that I will tell you about below. Does this mean you can never have these foods again? Not necessarily,  but it is a little complicated.

During the Low FODMAP Phase of the low FODMAP diet, it is important to keep the consumption of fructans to within the limits outlined by the Monash University Low FODMAP app portion sizes. For some foods like garlic and onions, most people will have to avoid them completely. For other foods like wheat, you can have small amounts. This may come as a surprise to some of you who may have cut out wheat completely or been advised to do so.

We are going to talk about some of the most common fructans like garlic, onion, and wheat. Read on to find out how to enjoy them while still eating low FODMAP.

How to enjoy fructans

Being a dietitian, I love food. I love to help people enjoy food as much as possible, especially the healthy varieties. Here’s how to enjoy fructans as much as you can while staying withing the limits or the low FODMAP diet.


When I talk about limiting garlic, most people look a little confused. Isn’t garlic healthy? It is, but, garlic contains fructans which as you know, ferment very rapidly in the colon. The limit for plain old garlic is zero. I generally only recommend the certified low FODMAP garlic oils because it is difficult to know how all of the other garlic oils are made. In Canada, you can order Monash certified garlic infused oil online from FODY Foods. In addition, FODY Foods offers all of  my clients a generous discount – lucky you!

Cooking with garlic infused oil is so much easier than peeling and chopping garlic. You can also drizzle it on salads, steamed veggies, pasta, soups or any dish you want to enjoy with garlic flavour. Mix it with lemon juice, mayo and anchovy paste for a spectacular 2 minute garlic Caesar salad dressing.

Why not make your own garlic flavoured oil?

To make your own, slice each garlic clove into about 4 large chunks and simmer in a frying pan with oil. Don’t turn your back on these little guys, they burn really quickly. The garlic flavour will blend with the oil while the FODMAPs remain in the chunks. The FODMAPs do not leach into the oil, but the flavour does. After a few minutes, remove the chunks and you will be left with a lovely garlic flavour, no fructans. Please note that this rule does not apply to cooking high FODMAP foods in water because the FODMAPs will diffuse into the water. Therefore, you can’t cook a stew with onions and just remove the onions because the water soluble FODMAPs will leach into the stew.

If you make extra infused oil to save for later, it needs to be stored in the fridge and will only last for 3-4 days. Unlike the store bought type, the home made version is not shelf stable and could make you sick if kept for too long or not refrigerated.

Time saving tip: For making your own garlic infused oil, buy peeled garlic and use about 2-3 times the amount of garlic that the recipes calls for.


Raw onion

The bulb of onions (red, white, yellow and leeks) contain fructans so the bulb needs to be limited during the Low FODMAP Phase. However, the green tops of green onions and chives are low FODMAP so they make a perfect replacement in dishes with raw onions. They also make a spectacular garnish for salads, soups, tacos, burritos, stews etc. Green onion tops can make just about any dish delicious in my opinion.

Time saving tip: Chop extra green onion tips or chives and store in a container with some paper towel. They will keep for about 3-5 days.

Cooked onion

To replace cooked onion, you can chop an equivalent amount of the green part of a leak. I find sautéed leak leaves work really well for soup, spaghetti sauce, stuffing and many other dishes that call for fried onions. Leak tops are easy to find at every grocery store.


Most people like to blame their problems on gluten. Poor gluten takes the blame for a lot of problems. If you have celiac disease (allergy to gluten), then gluten really is the problem and you have follow a strict gluten free diet for life. There’s also a new condition called non celiac gluten sensitivity that has a interesting body of research behind it. However with IBS, it is the fructans in wheat that cause digestive problems. Luckily, with IBS you don’t have to cut out wheat altogether as the low FODMAP diet is not as strict as you may think. What most people don’t know is that you can have small amounts of wheat. Low FODMAP does not mean wheat free or gluten free.

According to the Monash University Low FODMAP app, traditional sourdough made from wheat is low FODMAP at 2 slices (100 grams) and traditional spelt sourdough is low FODMAP at 2 slices (82 grams). I have a few clients who are self-proclaimed bread snobs who were thrilled to hear this news!! By owning a small kitchen scale (available in most grocery stores for $10) you can weigh your bread to make sure you are within the limit. Traditionally made sourdough bread is easier to digest because the long rising process allows the bacteria in the sourdough starter to break down (or digest) the fructans. Therefore, a traditional sourdough loaf that was given a lengthy time to rise (over 24 hours), will be lower in fructans.

Not all sourdough breads are low FODMAP. In order to choose the right sourdough, you need to watch for other high FODMAP ingredients like honey and agave and yeast. Yeast is low FODMAP, so it is not the problem. However, yeast is sometimes added to sourdough to accelerate the rising process which shortens the time the bacteria has to digest the fructans leaving more fructans for you. Therefore, don’t buy the variety with yeast.

In a nutshell, here is what to look for with sourdough bread:

  • Made from wheat or spelt flour
  • No other high FODMAP ingredients
  • No yeast
  • Long rise (more than 24 hours)

Gluten Free Bread

Another convenient option is gluten free bread which is now universally available in grocery stores. Lucky for us, the quality has greatly improved over the past few years. I remember trying my first piece of gluten free bread as a nutrition intern almost 20 years ago and it was horrible! But, gluten free does not necessarily mean low FODMAP! It is common for high FODMAP ingredients to be added to gluten free breads.

Here’s a list of what to look for when choosing a gluten free bread:

  • No high FODMAP flours – rye, barley
  • No high FODMAP ingredients – agave, honey, fruit juice, milk etc.
  • No added fibres like inulin

In all my nutrition programs, I provide a list of low FODMAP gluten free breads or will check for FODMAP ingredient if you email me the label.


I bet you didn’t know that a small amount of wheat pasta is allowed on the low FODMAP diet? According to Monash University, ½ cup of wheat pasta is low FODMAP. As a dietitian, I encourage everyone to limit pasta to a side dish portion, regardless of whether you have IBS or not.

Another great option for Italian style meals is gluten free pasta. My personal favourite is quinoa pasta because it tastes amazing, doesn’t get soggy and contains more protein and iron than wheat pasta. No one in my family can tell that it’s not wheat. For Asian dishes, rice noodles are perfect.  They contain only rice and cook in less than 5 minutes. They are available in the Asian section of your grocery store so therefore don’t contain the specialty gluten free price tag.


I hope you have enjoyed this article and that you learned that the low FODMAP diet is not as restrictive as you thought! Hopefully you have picked up a few great ideas to make this awesome diet easier and more delicious for you. The low FODMAP diet is a great solution for so many people but learning how to limit the FODMAPs can be tricky. Feel free to email me if you have questions. I offer a free call and I would love to hear from you.

Best of luck and bon appetite!

About Audrey:

I am a registered dietitian who specializes in IBS and the low FODMAP diet. I am based in Edmonton, Canada and I offer nutrition counselling by phone and video to anyone across Canada. If you are looking for help, have a look at my nutrition counselling page or get in touch for a free appointment.


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By |2018-12-18T19:38:32-07:00December 15th, 2016|FODMAP articles|6 Comments


  1. Mary MacDonald December 16, 2016 at 6:50 pm

    HI Audrey. This was a great article. I am going crazy with way too many things going on now! Mostly music ! Centennial Choirs concerts were last weekend- I am on the executive. So, details to look after. Also am choir director and play at our church and there have been more activities than usual. Throw in grandkids, Christmas parties for every group- Bah! Humbug! – and it is insane. I sincerely hope to seriously get back to you in Jan!
    Have a wonderful Christmas with your family. I believe you are going to be in Ottawa. Enjoy.

    • IBSnutrition December 17, 2016 at 8:16 am

      It is definitely a busy time of the year! Have a wonderful Christmas and I look forward to catching up in January.

  2. Donna December 28, 2016 at 2:52 pm

    Well done article! Personally, I would add buckwheat sourdough just cause. 🙂 I think I need to try making that ceasar salad dressing….I miss it so!

    • IBSnutrition December 29, 2016 at 6:21 pm

      Thanks Donna! I heard that Planet Organic has a delicious sourdough teff bread worth trying. The Caesar salad dressing is really good and so fast. It’s not the traditional recipe with egg yolk but it does in a pinch.

  3. Louise February 8, 2017 at 9:16 am

    Hello Audrey,
    I must try the infused oil,sounds yummy. Your article is very informative,so much to learn yet.
    I would like to know when a weight is given for a portion like pasta,is it before or after cooking it?
    Thank you for taking the time to inform us.

    • IBSnutrition February 28, 2017 at 10:57 am

      Great question. According to the Monash app, the weight is for cooked pasta.

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