Gluten Corner

Sourdough Bread – Approved For Those With Gluten Sensitivity?

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If you follow a gluten-free diet, whether it’s because of non-celiac gluten sensitivity (NCGS) or for other health reasons, a good slice of bread may be one of the main things you miss from your previous diet. But science shows that you may not have to miss out after all, and sourdough bread might be your solution!

First let’s take a look at sourdough bread and what makes it so different from other breads. Sourdough bread (the traditional way of making gluten-containing bread prior to the mid 1600’s), instead of baker’s yeast, is made with a starter culture rich in Lactobacilli bacteria. Why is this so important? Lactobacilli, besides being great for the gut microbiome, makes the bread more nutrient rich by neutralizing the undesirable phosphorus, or phytic acid, found in the wheat’s bran. (Studies show that sourdough fermentation can neutralize phytic acid by up to 90%). Phytic acid in conventional bread binds to important minerals like calcium, zinc, iron, and magnesium, making these nutrients bio-unavailable to us, meaning we are unable to absorb them. Sourdough bread is also baked at a low temperature, which helps preserve the nutritional value of the grain, and for a longer period of time, which aids in breaking down the gluten protein. Being a fermented food, sourdough is rich in prebiotic and probiotic bacteria, acting as a positive aid in balancing the microbiome. 

A study published in Applied and Environmental Biology was conducted in celiac patients to observe how well they tolerated sourdough bread. The study consisted of 17 celiac patients and two phases. In the first phase, participants were given 2 grams of gluten-containing bread baked with either baker’s yeast or a normal lactobacilli culture (which isn’t considered true sourdough). 13 out of the 17 experienced increased intestinal permeability, a hallmark of consuming gluten in celiac patients.

In the second phase, all participants were given 2 grams of a bread prepared with a true sourdough starter, categorized as a lactobacilli-rich culture able to break down the primary protein building block that triggers an immune response in those with celiac disease. The bread consisted of one-third wheat flour, and a mixture of oat, millet, and buckwheat flours. Surprisingly, increased intestinal permeability was not observed in any of the participants. 

While this study is promising, the sourdough starter used in this study is not commercially available, and therefore celiac patients are not cleared to consume sourdough breads.

Other recent studies published in 2018 and 2019 highlight the idea that FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols), not gluten, are the problematic factor in gluten-containing foods for some patients with irritable bowel syndrome, NCGS, and other functional GI conditions, and that true sourdough products, which are naturally low in FODMAPs, might be a desirable replacement for conventional gluten-containing products. Whether it’s FODMAPs and/or gluten that are problematic in this population, “true” sourdough seems to be tolerated with no physiological or biological symptoms experienced. 

If you’re someone with NCGS, which is estimated at approximately 10 to 15% of the worldwide population and growing, or if you’re on a gluten-free diet for other health reasons (excluding celiac disease), you can most likely enjoy a “true” sourdough bread from time to time with no issues. While sourdough breads made with an optimal starter contain beneficial bacteria, are more nutrient dense, and have lower gluten and FODMAP concentrations than other breads, it’s still bread (exponentially inferior to vegetables, fruits, nuts, and seeds) and should be consumed in moderation. The breads available at your local supermarket (even those labeled organic) are most likely not made with a high quality sourdough starter, and should be avoided. And remember, those with celiac disease should avoid ALL sourdough breads until more research is conducted.

If you want to try a high quality sourdough bread, we recommend baking one at home with a true sourdough starter instead of purchasing one from a bakery or supermarket. The nutritional and microbial benefits will be worth it! 

Leslie Ann received her BA from the University of Notre Dame and has a Master’s degree in Public Health and Nutrition from Johns Hopkins University. With over a decade of experience working in the health and wellness field as a nutritionist, health writer, and project manager, Leslie Ann is the backbone of the Gutbliss team, overseeing operations as well as the strategic mission of Gutbliss Rx, and authoring much of the content on the site. As a certified yoga teacher and personal trainer, she is an avid believer in integrative methods to treat and heal the body.

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