Why is Sourdough Better Tolerated for IBS & the Low FODMAP Diet?

When you embark on a low FODMAP diet, wheat is one of the hardest parts to give up, because there aren’t as many low FODMAP alternatives for bread. But what you may not realize is that small amounts of wheat are actually low FODMAP. Wheat breads are made with wheat flour and quickly become high FODMAP, but traditional sourdough bread is actually lower in FODMAPs and may be better tolerated. I should clarify that low FODMAP is not the same thing as gluten free. If you’re on a strict gluten-free diet due to celiac disease, then this post is not applicable to you.

Why are regular breads high FODMAP?

There is a carbohydrate component of both wheat and rye called fructan that is one of the FODMAP subgroups. It’s also found in garlic and onion.

Why is sourdough bread better tolerated?

Sourdough bread is still made with wheat, but is actually lower in fructan. Traditional sourdough bread goes through a different process than other breads. Most breads are made using baker’s yeast, which shortens the fermentation process. Fermentation is Sourdough is made using a “starter,” instead of baker’s yeast. This is a culture of flour and water, that is made over many days, which produces yeast and lactobacilli. The starter is mixed with the bread dough and ferments over many days. The bacteria and yeast remove many of the fructans from the wheat. The longer fermentation and leavening steps in the bread making process, the lower the fructan content of the wheat.

Don’t get too excited, though, because all sourdough breads aren’t made this way. If the bread you’re eying at the store has yeast or other additives on the ingredients list, chances are it wasn’t made the traditional way. What you want to look for are simple ingredients: flour, water, salt, and starter (sometimes listed, sometimes not). If you’re purchasing from a local bakery or market, you can ask if it was made using traditional techniques, like slow fermentation and with a starter. You may also want to check that no high FODMAP flavor additives are in the bread, including high-fructose corn syrup, honey, onion, and garlic.

If you want to incorporate sourdough bread into your low FODMAP lifestyle, stick to 1-2 slices per day. You can avoid during the elimination phase and bring back as part of your fructan reintroductions if you want to to make sure you tolerate it. You may also be able to find sourdough made from lower FODMAP flours, like oat or spelt, which may allow a larger portion size.

My recommendation is to start with sourdough from a local bakery. You’ll most likely find traditionally made sourdough bread, plus you’ll be supporting your local economy! If you want to be creative, you could also start making your own sourdough bread. This book may be able to help you get started!