Is Sourdough Healthier Than Yeast Breads?

Short answer: Yes.

Compared to yeast breads or breads leavened exclusively with commercial yeast, sourdough is fermented for a longer period, anywhere from several hours to a few days. During this process, the sourdough bacteria (lactobacilli) produce lactic acid, which raises the dough’s acidity and activates various enzymes (biochemical catalysts) in wheat and other related grains. Under the correct conditions, this effect results in the following 4 health benefits:

1. Less Phytic Acid, More Minerals

Whole wheat breads are excellent sources of minerals. However, they also contain phytic acid which binds to important minerals and prohibits mineral absorption. One of the few ways to break down phytic acid and increase mineral availability in whole wheat breads is to acidify the dough.

Whole wheat sourdough bread

Whole wheat breads: excellent sources of minerals and anti-minerals
(Photos courtesy of Marcus)

 

2. Degradation of Gluten

Gluten consists of two proteins: glutenin and gliaden. Both proteins are found in wheat and other related grains such as barley and rye. Moreover, studies have shown that gluten is degraded when the dough is acidified through sourdough fermentation. Consequently, this opens up the possibility of safer breads for people with gluten sensitivity.

Gluten proteins: glutenin and gliadin

Left: Diagram of gluten proteins and their interactions; right: scan electron micrograph of gluten
(Photo courtesy of the American Physiological Society)

 

3. Improved Blood Sugar and Insulin Response

According to a few studies, the buildup of lactic acid produced by sourdough bacteria may delay starch digestibility, which results in lower glycemic (blood sugar / glucose) and insulin responses. The reduction of simple sugars during sourdough fermentation may also contribute to such effects. Thus, sourdough breads may be beneficial to diabetics.

Idealized post-meal blood sugar & insulin level chart

Idealized post-meal blood sugar & insulin level chart
(Photo courtesy of Frontiers in Bioscience)

 

4. Improved Shelf Life

Sourdough has the potential to improve the shelf life of breads, thereby limiting or omitting the use of chemical preservatives. Studies have also reported that higher acidity in breads may hinder staling (starch retrogradation) and inhibit the growth of rope spoilage bacteria. In addition to that, sourdough bacteria have been observed to generate compounds to ward off mold.

Bread Mold

Mold: acceptable on cheeses; not acceptable on breads

 

Summary: compared to yeast breads, sourdough breads contain less phytic acid, has better mineral absorption properties, has potential health benefits to gluten sensitive individuals and diabetics, and requires less or no chemical preservatives.


Source(s):

1: Fermentation Processes Using Lactic Acid Bacteria Producing Bacteriocins for Preservation and Improving Functional Properties of Food Products. Advances in Applied Biotechnology.
2: Gluten Hydrolysis and Depolymerization During Sourdough Fermentation. Journal of Agricultural and Food Chemistry.
3: Highly Efficient Gluten Degradation by Lactobacilli and Fungal Proteases During Food Processing: New Perspectives for Celiac Disease. Applied and Environmental Microbiology.
4: Inhibition of Mold Growth by Sourdough Bread Cultures. RURALS.
5: Sourdough and Cereal Fermentation in a Nutritional Perspective. Food Microbiology.
6: Sourdough: A Tool for the Improved Flavour, Texture and Shelf-Life of Wheat Bread. VTT Biotechnology.
7: Sourdough-Leavened Bread Improves Postprandial Glucose and Insulin Plasma Levels in Subjects with Impaired Glucose Tolerance. Acta Diabetologica.
8: The Importance of Lactic Acid Bacteria for Phytate Degradation During Cereal Dough Fermentation. Journal of Agricultural and Food Chemistry.
9: Zonulin and Its Regulation of Intestinal Barrier Function. American Physiological Society.


Author: Zita (bakingbadly)
Published: January 29th, 2014
Last Modified: July 20th, 2014



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