Sourdough in the time of pandemic


2020 is, among other things, The Year of Sourdough. When everyone started baking last spring, yeast disappeared from store shelves. That’s a deal-breaker for anyone who wanted to bake bread, such as myself. I’ve been baking bread for decades, sometimes 2-3 times per week, so I was definitely worried. What to do? Learn to make sourdough.

Fortunately a local artisanal bakery was handing out free sourdough starter, which made it easy to get going. Traditionally people made their own sourdough by mixing flour and water and letting it sit out in the kitchen for a few days. The mixture picked up yeast and bacteria that were present in the environment, which started fermenting the dough. Depending on your kitchen or geographic location, your sourdough starter could end up with a distinctly unique microbial profile. For example, San Francisco sourdough is unique because the unique climate and environment encourage a unique mix of microbes in local sourdough.

Sourdough starter – overflowing!

Whatever the mix, sourdough bread has a unique flavor and texture, chewy and delightful. After months of eating nothing but sourdough, I’m not sure I could ever be satisfied with regular yeast bread again. But could there be health reasons to prefer real sourdough? I’ve been hearing rumors and anecdotes over the past few months. According to some people, sourdough is easier to digest, or better tolerated by people who are “gluten sensitive” (NOTE: this term has no official medical diagnostic criteria).

What’s the evidence? There have been some studies on sourdough bread. One study compared the molecular composition of sourdough breads to yeast breads made with the same flours (wheat and rye). Sourdough breads had significantly more of certain substances produced by fermentation, notably branched chain amino acids (BCAA) and phenolic acids. Rye flour showed more of these differences than wheat flour.

Is any of this healthier? The authors noted that, for example, branched chain amino acids may have a beneficial effect on insulin response. Whether the increased BCAAs in sourdough bread create that benefit was not investigated.

Why would sourdough be different from yeast bread made with the same flours? Yeast breads are not fermented in the same way. Sourdough fermentation involves yeast and lactic acid bacteria, which create the tangy taste, similar to yogurt. Yeast bread just uses yeast; there is no bacterial fermentation. Commercial yeast breads also include dough conditioners. Commercial “sourdough” may not be fermented at all — it may just be yeast bread with a sour flavoring, more like “soured” dough. The benefits of fermentation are absent.


No, sourdough bread is not gluten-free. Gluten — a protein in wheat flour — is essential to the structure and texture of sourdough bread. Why do some supposedly “gluten-sentitive” people tolerate sourdough? Perhaps because gluten isn’t actually their problem. Commercial yeast breads have a lot of other additives. Plus there are all the molecular changes noted above from the fermentation process, which might improve digestibility for certain people.

My advice: if you tolerate sourdough bread better than yeast bread (particularly commercial yeast breads), then you should go with your gut, so to speak. Enjoy!

Nutritionally superior?

In fact, sourdough is nutritionally very similar to any other type of bread made with wheat and/or rye flour. Calories, vitamins, minerals and so forth are not significantly different. And of course, fiber content depends on how much whole grain flour is used.

Better for digestion?

There isn’t a lot of good information on the general effect of sourdough bread on digestion. There is some research on irritable bowel syndrome and FODMAPS diets. One such study found no improvement for IBS patients eating sourdough compared to regular yeast bread. There isn’t much evidence that sourdough bread is tolerated any better than regular bread. However if you believe it’s helpful for you, then you … go with your gut.

I’d like to see research on the impact of sourdough bread consumption on gut microbe populations. That might actually be more relevant to health. We know gut microbes impact health in many ways, from inflammation to brain function. Perhaps the unique molecular composition of sourdough impacts gut microbes and therefore health.

Meanwhile if you’ve got access to real sourdough (baked at home or from a bakery) — Enjoy! Sourdough the original method of preparing bread, whether flat breads or loaf breads. People have been eating sourdough breads for thousands of years. Modern yeast breads really haven’t improved on that at all.

Copyright: All content © 2021 Nutrition Strategy Advisors LLC. Photographs © Donna P Feldman, unless otherwise attributed. Reproduction or use without permission is prohibited.