The Truth About Probiotics In Sourdough Bread

Ever wondered if sourdough bread has those gut-friendly probiotics we’re all hearing about?

Here’s the scoop: sourdough starter is packed with probiotic yeast, but baking tends to kill off these good guys.

However, some recent studies are shaking things up, suggesting that probiotics don’t die during baking – they merely go inactive, and a few days on the counter brings them right back.

But wait, there’s more… sourdough isn’t just about probiotics. It also contains postbiotics, or the beneficial compounds produced by probiotics! Postbiotics don’t need living cells to be good for your health.

Let’s dive into the world of sourdough and probiotics.

What Are Probiotics?

Probiotics are live, beneficial microorganisms that help maintain a healthy balance of bacteria in your gut.

They include certain types of bacteria, like:

• Lactobacillus
• Bifidobacterium
• Saccharomyces boulardii

These friendly microbes work by competing with bad bacteria for resources and strengthening the gut barrier (Source).

While not all probiotics work the same way, they’re generally known for being really good for your digestive system.

Probiotics vs Prebiotics vs Postbiotics

When we talk about probiotics in sourdough, we also need to talk about postbiotics.

But what the heck is the difference?

The National Institute of Health explains probiotics vs prebiotics vs postbiotics perfectly:

Probiotics are live beneficial microbes, prebiotics are food for these microbes, and postbiotics are the beneficial compounds produced by probiotics.

Keep this in mind as we continue the conversation about probiotics and sourdough.

Does Sourdough Contain Probiotics?

Sourdough starter is a culture of probiotic yeast and lactic acid bacteria. So, yes – sourdough starter contains probiotics.

When you bake the bread, the high heat of the oven is thought to kill most of those probiotics. However, that’s not set in stone.

Different conditions (like varying temperatures, how long you bake the bread, and the hydration of the dough) can influence the heat resistance of some bioproducts.

As a simple example, bacteria are better at resisting heat if the moisture content is lower (Source).

Lactobacillus plantarum P8

What I read about Lactobacillus plantarum P8, specifically, was mind-blowing.

Apparently, this “good” bacteria goes inactive during baking. However, it turns out the bacteria simply need to recover from the baking process. With a little time, they can adapt to their new environment (Source)!

Researchers found that L. plantarum started growing back in the bread while it was stored.

It increased in number by 2-3x after 4 days of storage. The levels stayed high for a few more days.

So, if you really want to benefit from probiotics in sourdough, consider letting it fully cool overnight and enjoy it throughout the week.

Postbiotics in Sourdough

Postbiotics – or the beneficial compounds produced by probiotics – are thought to remain in the bread during and after baking.

If you’re into the scientific part of this, here’s an excerpt from the research I relied on heavily to write this article:

“During the baking process, cell lysis of microorganisms delivers cellular debris that may also have beneficial properties functioning as postbiotics. Examples of postbiotic compounds that are present in sourdough are short-chain fatty acids (SCFAs), secreted proteins/peptides, bacteriocins, secreted biosurfactants, amino acids, flavonoids, EPS, vitamins, organic acids, and other molecules discussed in this review. Remains of microbial cell structures such as peptidoglycan from bacterial cell walls, pili, fimbriae, flagella, cell-surface-associated proteins, cell-wall-bound biosurfactants, and cell supernatants are also postbiotic components that have potential health benefits in the host.”

Why Probiotics In Sourdough Matter

Here’s why people like me get all excited about probiotics and postbiotics in sourdough bread.

The gist is the probiotics from sourdough pre-digest molecules that aren’t nutritious, which is SO good for your gastrointestinal health.

The results for our health?

• Stabilized cholesterol levels
• Anti-inflammatory effects
• Lower glycemic index (lower speed at which sugar enters our body’s bloodstream)

The research is still going on, but you may also experience positive benefits like:

• Stress and anxiety relief
• Strengthened immune system
• Cancer prevention

I don’t know about you, but what I’m hearing is that sourdough is not only delicious, but it’s a total miracle food!

Probiotics in Sourdough FAQs

Does sourdough bread have probiotics?

Sourdough bread has probiotics, but they either die or go inactive during the baking process. However, recent research is showing those inactive probiotics acclimate to their new environment during storage and actually start increasing again. Plus, aside from probiotics, postbiotics remain; they have great health benefits, too!

Does baking sourdough kill probiotics?

Baking sourdough bread does tend to harm the probiotics in the dough. However, recent research is showing that some strains, like Lactobacillus plantarum P8, merely go inactive during baking. During storage, they appear to come back to life and start multiplying again. More research is needed, but this is super exciting!

Does freezing sourdough kill probiotics?

The research I read focused on probiotics’ resistance to high heat in the oven – not the cold of a freezer.

That said, I’d like to make an educated guess here and say that no, I don’t think freezing baked sourdough bread will kill all the good microbes. You can freeze an active sourdough starter and bring it back to life (it should keep for a few months in the freezer). If those microbes can survive in a sourdough starter, I’d make an educated guess that the same ones can survive in baked sourdough bread.

Does sourdough discard have probiotics?

Sourdough starter is a mixture of probiotic yeast and lactic acid bacteria, so it’s safe to say that sourdough discard – or inactive starter – does contain probiotics. Are they at their healthiest and strongest? Definitely not. But a nice feeding will perk the starter right up and getting those helpful microbes multiplying again.

Conclusion

All of the studies I combed through made one thing clear: more research is needed.

We still don’t fully know what kinds of yeast and bacteria are in sourdough starters, and they vary from one starter to the next.

We’re getting closer, though – The Global Sourdough Project got 560 samples of different sourdough starters from around the world and discovered over 70 different types of yeast!

While I’ll patiently await more information, one thing’s for sure: sourdough bread is incredibly good for your health, in more ways than one.

Further Reading: 27 Top Benefits of Sourdough Bread + Why It’s Good For You