How long does it take to digest bread?

In this brief study, we will answer the question, “how long does it take to digest bread?” followed by describing the carbohydrate digestion and effects of regular bread consumption.

How long does it take to digest bread?

When eating bread, it takes 2 to 4 hours for the stomach to perform its whole function to digest it. Following that, it passes through the small and large intestines. (1)

What is the nutritional content of bread?

Bread boasts a substantial amount of complex carbohydrates, mainly in the form of starch, constituting approximately 90% of its total carbohydrate content. Within this starch, around 1-2% exists as resistant starch. 

Additionally, small quantities of other polysaccharides like cellulose, hemicellulose, and lignin can be found in bread. As starch breaks down during digestion, dextrins, maltose, and glucose are produced.

The bran of cereals holds most of the dietary fiber, which is a crucial component for digestive health. However, in the process of obtaining white flour for white bread production, the bran is removed, leading to a significant reduction in fiber content. (2)

What are the types of bread?

In general, there are three types of bread cereal/dough sources worldwide, which are wheat bread (with gluten), bread without gluten and combined bread. Bread can provide 1.2% of protein, 60% of thiamine and niacin, 40% of calcium and 80% of the daily iron needed by an adult. (3)

In contrast to white bread, whole grain bread, which retains the bran, contains substantially higher amounts of dietary fiber.

Furthermore, the fiber content in bread can be further increased by incorporating additional ingredients like oats, grains, or seeds into the recipe. This addition not only enhances the fiber content but also introduces valuable nutrients and textures to the bread. (2)

What is the process of bread digestion?

Digestion begins with the process of mastication, or chewing, where ingested food is both reduced in size and lubricated with saliva.

Bread’s porous physical structure, resulting from the baking process, mechanical kneading, and the activity of baking yeasts, makes it highly susceptible to breakdown in the mouth and stomach. 

During the gastric digestion process, multiple phenomena are occurring simultaneously. Gastric juice is migrating into the bread, causing enzymatic degradation and acid hydrolysis. The bread is also being broken apart by mechanical movement of the stomach walls.

Within 4 hours of stomach digestion, the starch granules become detached from the protein network they were initially embedded in. 

As a result of bucco-gastric digestion, the size of bread particles is significantly reduced, promoting easier access for pancreatic amylases to break down the starch further in the small intestine. (4, 5)

How does bread type affect digestion?

The disintegration rate and profile of bread are notably impacted by the type of bread. 

This variation can be primarily attributed to differences in water absorption, influenced by factors such as initial moisture content, water holding capacity, and internal structure of the bread.

While the addition of acid has only a limited effect on bread disintegration, the primary factor contributing to disintegration is dissolution in water or gastric juice. 

Moreover, an increase in saliva content in the bread results in higher moisture levels, reduced cohesive forces, and increased bread disintegration.

The presence of α-amylase significantly softens the bread texture and leads to an enhanced disintegration of the bread. However, the relative impact of α-amylase on bread cohesive force and disintegration varies depending on the type of bread. (5)

What are the health benefits of bread consumption?

Bread serves as an exceptional source of complex carbohydrates, supplying the body with essential energy while contributing to the maintenance of balanced blood glucose levels. 

Additionally, most bread types offer a source of low-fat vegetable protein, albeit in moderate amounts. 

They are also rich in essential nutrients, including B vitamins, vitamin E, and trace elements like iron, potassium, calcium, and selenium, all of which play vital roles in supporting various bodily functions.

Vitamin B is crucial for protein metabolism and cell replacement, while vitamin E acts as an active antioxidant, protecting cells from oxidative damage. 

Iron is essential for growth and facilitates proper oxygenation of cells, potassium supports the balanced function of cells, and calcium contributes to maintaining bone density. 

Lastly, selenium, being a powerful antioxidant, further enhances the body’s defense against oxidative stress and free radicals. (6)

What are the side effects of bread consumption?

Bread has a role in various health conditions that can burden the human body, particularly in the case of obesity. Consuming excessive amounts of bread, especially within an unbalanced diet, can contribute to obesity. 

Bread’s high glycemic index leads to increased sugar and insulin secretion, further exacerbating the risk of obesity, especially when not part of a well-balanced diet.

To maintain a balanced diet, carbohydrates should constitute about 50% of the daily intake, and including two slices of whole-wheat bread per day can be a suitable choice.

For individuals sensitive to gluten, which is present in bread, the consumption of bread can trigger celiac disease. This condition manifests with symptoms like diarrhea, weight loss, undernutrition, anemia, osteopenia, and psychiatric disorders such as irritability. 

To manage their condition effectively, individuals with celiac disease should avoid consuming grains that contain gluten, such as barley, rye, oats, and wheat. (6)

Other FAQs about Bread that you may be interested in.

Is it safe to eat every variety of bagels during pregnancy?

Can you eat bread without a gallbladder?

Can you defrost pita bread in the microwave?

Conclusion

In this brief study, we answered the question, “how long does it take to digest bread?” followed by describing the carbohydrate digestion and effects of regular bread consumption.

Reference

1. Kurek, M.A., Wyrwisz, J., Karp, S. et al. Effect of fiber sources on fatty acids profile, glycemic index, and phenolic compound content of in vitro digested fortified wheat bread. J Food Sci Technol 55, 1632–1640; 2018.
2. Ros Miller, Sara Stanner. A summary of evidence on the digestion, absorption and metabolism of white bread carbohydrates. The British Nutrition Foundation. 2016
3. Aghalari, Z., Dahms, HU. & Sillanpää, M. Evaluation of nutrients in bread: a systematic review. J Health Popul Nutr 41, 50; 2022.
4. Fardet, A., Leenhardt, F., Lioger, D., Scalbert, A., & Rémésy, C. Parameters controlling the glycaemic response to breads. Nutrition Research Reviews, 19(01), 18. 2006.
5. Bornhorst, G.M., Singh, R.P. Kinetics of in Vitro Bread Bolus Digestion with Varying Oral and Gastric Digestion Parameters. Food Biophysics 8, 50–59 2013.
6. Kourkouta, Lambrini & Koukourikos, & Iliadis, & Ouzounakis, & Monios, Alexandros & Tsaloglidou,. Bread and Health. Journal of Pharmacy and Pharmacology. 2017.