2 Jul 2025
For thousands of years, bread has been a staple food, yet many consumers may not fully understand how different types of bread affect digestion. The ingredients, fiber content, and fermentation process all play a role in how bread is broken down in the body, influencing digestion time and overall gut health.
Some breads support microbiome diversity and help regulate digestion, while others may contribute to discomfort. However, according to Taste Tomorrow1, 74% of consumers actively seek gut-friendly foods. There is a clear demand for products that promote better digestion.
At Puratos, we recognize that bakers and food manufacturers have an opportunity to meet this growing need by crafting bread that not only tastes great but also supports digestive wellness. By understanding how bread is digested step by step, and how factors like fiber, fermentation, and processing impact its effects on gut health, bakers can create products that align with consumer expectations and provide real nutritional benefits – making them more than just a tasty daily staple.
This article explores the science behind bread digestion, how different formulations impact gut health, and how bakers can meet growing consumer demand with innovative, functional ingredients that improve bread’s digestibility.
How long does bread take to digest?
The digestion process of bread varies based on its fiber content, fermentation process, and overall nutrient composition. While the glycemic index (GI) is often mentioned in relation to digestion, it is actually a result of how the bread is digested and the types of nutrients it contains rather than a direct measure of digestion speed. GI reflects how quickly carbohydrates in the bread raise blood sugar levels after eating.
Refined white bread, which is low in fiber and often higher in rapidly digestible carbohydrates, breaks down quickly, leading to rapid blood sugar spikes. In contrast, whole grain and sourdough bread take longer to digest due to their higher fiber content and fermentation, which can slow carbohydrate absorption. This results in more sustained energy release and potential benefits for gut health13.
A study published in the Nutrients journal2 found that high-fiber bread consumption can double fiber intake, which significantly increases gut microbiome diversity and short-chain fatty acid (SCFA) production. SCFAs, made by microbes in the gut, help the body maintain a healthy immune system2. Since 90% of people worldwide do not meet the recommended 25g of daily fiber intake3, switching to fiber-rich breads can help improve digestion, gut health, and overall immunity.
To compare how different types of bread digest, here’s a breakdown of bread digestion time, glycemic impact, and gut health benefits:
Different types of bread affect the body in unique ways. For instance, sourdough bread digests slowly, leading to a steadier blood sugar response and better nutrient absorption7, 14, while white bread digests quickly9, often causing blood sugar spikes and offering little benefit for gut health16.
The science behind bread digestion
Understanding how bread is digested step by step helps explain why some breads are better for gut health.
Mouth: Digestion begins when enzymes in saliva break down carbohydrates into simple sugars. Chewing thoroughly helps by breaking the bread into smaller particles4.
Stomach: Gastric acids process the bread, further breaking down carbohydrates. White bread moves through the stomach quickly, while whole grain and sourdough bread take longer5, offering longer-lasting satiety and energy.
Small intestine: Nutrients such as vitamins, minerals, and carbohydrates are absorbed. Fiber in whole grain and sourdough bread slows sugar absorption, supports blood sugar balance, and feeds good gut bacteria6.
Large intestine: Remaining fiber moves into the colon, where it feeds beneficial gut bacteria, supports bowel movements, and reduces bloating.
Why sourdough is easier to digest
Sourdough bread is one of the most gut-friendly bread options due to its fermentation process. Studies show that people who eat fermented bread like sourdough experience lower blood sugar spikes than those who eat refined bread7.
The lactic acid bacteria in sourdough:
- Pre-digest gluten, making it easier for sensitive individuals to tolerate14.
- Reduce phytic acid, which blocks the absorption of minerals like magnesium and zinc7.
- Produce short-chain fatty acids (SCFAs), which, as previously mentioned, nourish gut bacteria and improve overall digestion15.
Because of its low glycemic index (GI), sourdough also releases energy gradually, preventing sugar crashes8, and keeping you full longer.
How does bread affect bowel movements?
Is bread good or bad for digestion? As previously discussed, the answer depends on fiber content and fermentation17. Whole grain and sourdough breads support bowel regularity9 by feeding beneficial gut bacteria15.
Studies show that high-fiber bread consumption increases short-chain fatty acids production18,15, improving gut function and overall digestion. On the other hand, low-fiber breads may contribute to sluggish digestion and bloating. Fiber also acts as a natural cleanser for the digestive tract, reducing the risk of constipation and digestive discomfort.
To ease the digestion and regular bowel movements, consumers are encouraged to look for breads that contain:
- At least 3g of fiber per serving9
- Whole grains (instead of refined flour)
- Fermented ingredients, such as sourdough starter
Common bread and digestion myths
There are many misconceptions about bread and gut health. Here’s what the science says:
Myth: "Bread causes bloating."
It depends on the type! Sourdough and high-fiber breads actually reduce bloating by improving digestion and feeding beneficial gut bacteria10.
Myth: "Gluten-free bread is always better for digestion."
Some gluten-free breads lack fiber, making them less beneficial for gut health than high-fiber or sourdough breads11.
Myth: "Bread is bad for gut health."
Fiber-rich and fermented breads support digestion by feeding good bacteria and promoting a healthy gut microbiome12.
The future of digestive health and bread
As more consumers explore the link between bread and digestion, there’s a clear movement toward high-fiber, sourdough, and whole grain breads. Choosing these options can support gut health, enhance nutrient absorption, and regulate digestion.
Future innovations in gut health will likely focus on personalized nutrition, where breads containing specific biotic ingredients (pre-, pro- and postbiotics) support individual digestive needs. With ongoing research in microbiome science, bakers have an opportunity to shape the future of functional foods. Learn why functional ingredients are gaining popularity.
Respond to the demand for gut-friendly bread
At Puratos, we combine baking expertise with science to help you create bread that’s not only delicious, but also beneficial for your health. With the right ingredients and support, you can meet the growing demand for gut-friendly products. Whether you're improving existing recipes or launching something new, Puratos is here to help. Contact your local Puratos representative to get started.
REFERENCES
- Taste Tomorrow – Puratos
- Swapping White for High-Fibre Bread Increases Faecal Abundance of Short-Chain Fatty Acid-Producing Bacteria and Microbiome Diversity: A Randomized, Controlled, Decentralized Trial – NIH
- Designing healthier bread through the lens of the gut microbiota – ScienceDirect
- The Benefits of Sourdough and Your Gut: A Guide to Digestive Health – The Sourdough Society
- Sourdough Microbiome Comparison and Benefits – NIH
- Impact of sourdough fermentation on nutrient transformations in cereal-based foods: Mechanisms, practical applications, and health implications – ScienceDirect
- What Makes Sourdough Healthier and Easy to Digest? – Cultured Guru
- Thirty years of knowledge on sourdough fermentation: A systematic review – ScienceDirect
- Bread Digestion Time – Medicover Hospitals
- Should you cut out bread to stop bloating? – Oxfordshire County Council
- The Gluten Free Diet: Bad or Good? – Gastro Health Partners
- How Brands Are Capitalising on Gut Health – FoodNavigator
- Sourdough Fermented Breads are More Digestible than Those Started with Baker's Yeast Alone: An In Vivo Challenge Dissecting Distinct Gastrointestinal Responses – NIH
- Sourdough and digestibility – Sustainable Food Trust
- The Power of Fiber: Transforming Bakery Products for Better Gut Health – Puratos
- Trust your gut: Growing interest in personalized nutrition and functional foods – Taste Tomorrow
- From donuts to cakes: the fermentation trend sweeps the patisserie industry – Taste Tomorrow
- Swapping White for High-Fibre Bread Increases Faecal Abundance of Short-Chain Fatty Acid-Producing Bacteria and Microbiome Diversity: A Randomized, Controlled, Decentralized Trial – NIH
Disclaimer: Puratos has provided the information here in good faith and based on the best of its current knowledge of the situation. It does not constitute regulatory advice and it is not a substitute for customers conducting their own legal/regulatory assessments to make their own decisions. You are encouraged to confirm this information with legal/regulatory advice from professionals familiar with your factual situation. Puratos does not accept any liability by reliance on this information.
