Is sourdough bread safe for a gluten-free diet? Here’s what you need to know

If you’re thinking of cutting out gluten, you’ve probably wondered whether sourdough bread is safe. 

With wheat-free diets becoming more popular among the health-conscious and people with digestive issues.

It’s important to ask: is the trendy loaf of sourdough bread truly gluten-free? 

The short answer: not unless it’s specifically made that way. Let’s unpack exactly what’s going on, in plain terms.

What is sourdough and how is it made?

Sourdough bread is made by mixing flour, water and salt with a “starter”, which is a living culture of wild yeasts and lactic acid bacteria. Unlike bread made with commercial baker’s yeast, sourdough uses this long fermentation process to leaven (rise) the dough through natural action of the microbes.

Because of the slower, natural fermentation, sourdough has a distinct flavour and texture, but also some interesting changes in how the flour is broken down.

Does sourdough bread contain gluten?

Yes - if the bread is made with wheat, rye or barley flour, it still contains gluten. The fermentation process does reduce some of the gluten proteins and can break them down into smaller molecules, but it does not eliminate gluten completely.

Why does sourdough feel easier to digest?

There are several reasons sourdough can feel gentler on the stomach:

• The long fermentation helps break down phytic acid and some carbohydrates that are harder to digest.
• The microbial action modifies the gluten structure and other proteins, which may reduce irritation for people with mild sensitivities.
• Some studies show sourdough has a lower glycaemic index (GI), meaning it may cause a slower rise in blood sugar.

These factors can matter because many people avoid wheat not necessarily because of full coeliac disease, but because of gut issues or perceptions of gluten sensitivity.

For those people, sourdough might be a better choice than a standard white loaf, but it’s still not the same as a gluten-free bread.

So, while some people with mild wheat sensitivity may digest sourdough more easily, for someone who must avoid gluten entirely, the standard sourdough loaf is not safe.

Gluten-free sourdough

There are sourdough breads made with gluten-free flours such as buckwheat, sorghum, rice or millet. These are safe for someone avoiding gluten, provided the production avoids cross-contamination and uses certified gluten-free ingredients. 

So, if you’re following a strict gluten-free diet, look for the label “gluten-free sourdough” rather than assuming every artisan sourdough loaf qualifies.

Putting it into context

• Many South African supermarket bakeries market “sourdough” as a premium loaf. If you’re on a wheat-free or gluten-avoidance plan, don’t assume every loaf is safe. Ask about the flour used.
• If you have true coeliac disease, you must avoid any sourdough made with wheat/rye/barley because gluten remains.
• If you’re just sensitive to wheat, have digestive issues, or want to choose bread that is more friendly to your gut, then a traditional sourdough could be a smart option - just be clear it still contains gluten.
• For children, family members or guests with gluten-free needs, seek out bakeries that offer certified gluten-free sourdough options, or consider making your own at home where you control the flour and conditions.

For those following gluten-free or wheat-free diets, the key is to ask the right questions: what flour is used? Is it certified gluten-free? If the answer is “no” or “wheat flour”, then that loaf of sourdough is not safe for a gluten-free diet.

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