06 August 2018

Can the ancient process of sourdough be used to create bread for people with IBS?

sourdough breads

By Jane Muir - Associate Professor, Head of Translational Nutrition Science

One common observation made by many of our patients returning from their European vacations - is that the bread in Europe is very different to the bread we have back home (in Australia and US).  Often people feel that they can ‘tolerate’ this bread. They wonder why.

Firstly, when on holiday you tend to be more relaxed which can help provide relief from IBS symptoms (read more on stress) but also there is something about breads made in many European countries that may explain why they may be better tolerated by people with IBS. 
European bakeries often use very traditional bread making practices that involve sourdough fermentation.  Our own research here at Monash has shown that the levels of FODMAPs (mostly fructans) are lower in breads made using traditional sourdough fermentation than standard bread made with modern bread making practices (Biesiekierski et al 2011, Varney et al 2017).  But why is this so?

The use of the sourdough fermentation process has been used by humans for thousands of years.  Traditionally, sourdough relied on ‘natural microorganisms’ from the environment where the bread was made (this can include insects that may be present in the flour and even the hands of the baker). 

The important microorganism involved in the production of sourdough bread are lactic acid bacteria and yeasts. It is the interaction of a number of different strains of yeasts and lactic acid bacteria that contribute to the final sourdough bread product. These microorganisms are responsible for the slightly sour taste that comes for the acids produced by fermentation (such as acetic acid and lactic acid). These acids also contribute to the naturally longer shelf-life of sourdough breads. The fermentation process also generates the gases that help with the rising process (essential for the aerated bread crumb).

A long proving time is very important with traditional sourdough breads, however this aspect of sourdough can be tricky (the sourdough microoganisms are very temperamental).  This is a major reason why yeasts (reliable, fast with no need of a long proving time) have replaced sourdough in modern bread baking practices today.  

But there is now a trend back to sourdough.  This may be particularly important for people with IBS.  It appears that the lactic acid bacteria and yeasts produce enzymes (called fructanase, invertase), which can degrade the fructans (Loponen & Gänzle 2018). The microorganisms in the fermentation process also utilize the released fructose.

Some sourdough microorganisms are better than others at breaking down fructans and the type of flour used can make a difference. So the final product does need to be tested for total FODMAP levels. It is certainly possible to select the right mix of the microorganisms to break down the FODMAPs in the bread to the level that will be well tolerated by most people with IBS.  
Look out for Monash University Low FODMAP certified sourdough breads – with some already certified and listed in our App. 


References:

Biesiekierski JR, Rosella O, Rose R, et al. Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals. J Hum Nutr Diet 2011;24:154-76.

Varney J, Barrett J, Scarlata K, et al. FODMAPs: food composition, defining cutoff values and international application. J Gastroenterol Hepatol 2017;32 Suppl 1:53-61.

Loponen, J., & Gänzle, M. G. (2018). Use of Sourdough in Low FODMAP Baking, 1–12. https://doi.org/10.3390/foods7070096




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