What kind of vitamins are in sourdough bread?

November 14, 2025 •

3 min read

According to scientific studies, the fermentation process in sourdough bread significantly increases the bioavailability of micronutrients by reducing phytic acid, making its vitamins more accessible to the body. This means when you ask, 'What kind of vitamins are in sourdough bread?', the answer includes a wide range of B vitamins and essential minerals that are more easily absorbed.

Quick Summary

Sourdough bread contains a beneficial profile of B vitamins, including thiamine, niacin, and folate, alongside essential minerals like iron and magnesium. The traditional long fermentation process enhances nutrient absorption by neutralizing antinutrients found in the grain. Specific vitamin content can vary with the flour and fermentation method.

Key Points

B Vitamin Rich: Sourdough bread contains several B vitamins, including B1, B2, B3, B5, B6, and B9 (folate).
Enhanced Mineral Absorption: The fermentation process neutralizes phytic acid, making essential minerals like iron, magnesium, zinc, and calcium more accessible to the body.
Potential B12 Source: While rare, specific starter cultures with P. freudenreichii can produce vitamin B12, which is typically found only in animal products.
Lower Glycemic Index: Sourdough fermentation alters carbohydrates, leading to a slower release of sugar and a lower glycemic response compared to regular bread.
Improved Digestibility: The breakdown of components during fermentation can make sourdough easier for some people to digest.
Antioxidant and Prebiotic Properties: Fermentation can increase antioxidant levels and creates prebiotics, which support a healthy gut microbiome.

A Rich Profile of B Vitamins and Other Nutrients

Sourdough bread is often celebrated for its complex flavor, but its nutritional benefits are equally impressive. The process of slow fermentation with wild yeast and lactic acid bacteria transforms the flour, creating a bread with an enriched nutritional profile, particularly when it comes to B vitamins and minerals.

The B-Vitamin Complex in Sourdough

Sourdough bread typically provides a range of B vitamins, which are crucial for energy metabolism, brain function, and cellular health.

Thiamine (B1): Essential for converting carbohydrates into energy, a single slice of sourdough can provide a notable percentage of your daily value.
Riboflavin (B2): Plays a key role in energy production, cellular growth, and the metabolism of fats, drugs, and steroids.
Niacin (B3): Important for over 200 different chemical reactions in the body, including converting food into energy.
Pantothenic Acid (B5): Contributes to the synthesis of coenzyme A, which is essential for fatty acid metabolism.
Pyridoxine (B6): Involved in more than 100 enzyme reactions, primarily concerning protein metabolism.
Folate (B9): Vital for cell growth and DNA formation. Sourdough fermentation can increase its availability.
Vitamin B12 (potentially): While not naturally present in significant amounts in most sourdough, some studies show that specific fermentation techniques using certain bacterial strains, like P. freudenreichii, can enrich the bread with B12, offering a potential plant-based source.

Minerals and Bioavailability

Beyond vitamins, sourdough fermentation enhances the accessibility of minerals already present in the flour. Grains contain phytic acid, an 'antinutrient' that binds to minerals and prevents their absorption. The lactic acid bacteria in sourdough produce phytase, an enzyme that breaks down phytic acid, unlocking minerals for the body. This process makes sourdough bread particularly rich in bioavailable:

Iron: Crucial for blood oxygen transport.
Calcium: Essential for bone health.
Magnesium: Regulates muscle and nerve function and helps produce protein.
Zinc: Important for immune function and cell division.
Manganese: Essential for bone formation and metabolism.
Selenium: A potent antioxidant that protects cells from damage.

Comparison: Sourdough vs. Commercial Bread

Understanding the differences between sourdough and conventionally made bread highlights why fermentation is so beneficial. The chart below contrasts the nutritional characteristics of typical commercial bread with traditional, long-fermented sourdough.


Feature	Traditional Sourdough Bread	Commercial Yeasted Bread
Leavening Agent	Wild yeast and lactic acid bacteria	Commercial baker's yeast
Fermentation Time	Long (typically 12-36+ hours)	Short (often under 2 hours)
Phytic Acid Levels	Significantly reduced, enhancing mineral absorption	High, hindering mineral absorption unless fortified
B Vitamin Levels	B vitamins are retained and often synthesized by microbes	Levels can be depleted due to rapid processing
Bioavailability	High, minerals like iron, zinc, and magnesium are more accessible	Lower, minerals are often bound by phytic acid
Gut Health	Acts as a prebiotic, feeding good gut bacteria	Minimal prebiotic effect due to rapid fermentation
Taste	Complex, tangy, and slightly sour	Typically mild and less complex

The Role of Fermentation Beyond Vitamins

Sourdough's nutritional advantages extend beyond its vitamin and mineral content. The fermentation process itself offers additional health benefits:

Improved Digestibility: The lactic acid bacteria predigest some of the flour's starches and proteins, including gluten, which can make it easier to digest for those with mild sensitivities.
Lower Glycemic Index: The fermentation process alters the carbohydrates in the bread, leading to a lower glycemic index. This results in a slower release of sugar into the bloodstream, helping to regulate blood sugar levels.
Prebiotic Properties: The dietary fiber in sourdough acts as a prebiotic, providing food for the beneficial bacteria in your gut and promoting a healthy microbiome.
Enhanced Antioxidant Content: Lactic acid fermentation can increase the levels of antioxidants in the bread, which help protect cells from damage and reduce inflammation.

Conclusion

While commercial bread may be fortified with certain vitamins, the traditional long-fermentation process of sourdough provides a more complete nutritional package. What kind of vitamins are in sourdough bread depends largely on the flour used, but the process itself ensures these nutrients are more bioavailable. From a wide array of B vitamins to essential minerals like iron and magnesium, sourdough offers a tangible nutritional upgrade. The reduction of phytic acid, coupled with improved digestibility and prebiotic properties, makes sourdough a superior choice for those seeking a nutritious and gut-friendly staple for their diet.

Learn more about sourdough's health benefits from expert dietitians(https://www.today.com/health/diet-fitness/is-sourdough-bread-healthy-rcna137707).

Frequently Asked Questions

Sourdough bread is particularly rich in a range of B vitamins, including thiamine (B1), riboflavin (B2), niacin (B3), folate (B9), and, depending on the flour, vitamin B6.

While the vitamin content largely depends on the original flour, the fermentation process can increase the bioavailability of vitamins and minerals. Some studies also show that certain microbial strains can synthesize additional vitamins like B12.

Yes, sourdough bread is a good source of folate (vitamin B9), and the fermentation process makes this vitamin more readily absorbed by the body compared to bread made with conventional yeast.

Sourdough’s primary advantage isn't necessarily having a higher initial quantity of vitamins, but rather that its fermentation process reduces phytic acid, which dramatically increases the body's ability to absorb the vitamins and minerals present.

It is not a reliable source of vitamin B12 unless fortified. However, research has shown that when fermented with specific bacteria like P. freudenreichii, it can produce nutritionally significant amounts of B12.

The fermentation process makes minerals such as iron, calcium, magnesium, and zinc more bioavailable by neutralizing phytic acid, which would otherwise inhibit their absorption.

Yes, the type of flour used directly impacts the nutritional profile. Whole grain flours, for example, contain a wider array of vitamins and minerals than refined white flours, and the fermentation process makes those nutrients more accessible.