Sourdough Bread and Glycemic Index

 By: Brooke Kurkjian

What trendy quarantine skill did you pick up? I chose sourdough. I love baking but have always been intimidated by the prospect of having to keep a jar full of flour and water alive. An abundance of time spent in the house, and a yeast shortage in my local grocery store, gave me the courage to try it out.

Image by Brooke Kurkjian

A little background on this mysterious fermented substance. Bread has been around forever. No matter where your ancestors come from, it’s guaranteed that they made some form of bread. Before the yeast we know today was available, people made leavened bread with wild yeast in the form of sourdough. The word sourdough can refer to the finished product and the starter - a mixture of flour and water. This mixture of flour and water combines bacteria (lactobacili) and wild yeast to bubble and create a substance that gives rise to the bread products we call sourdough. This process, called fermentation, gives a unique flavor to the bread (King Arthur Baking).

Image: https://www.kingarthurbaking.com/learn/guides/sourdough

What makes sourdough bread particularly interesting is its glycemic index. Glycemic index measures how quickly a food affects our blood sugar. Foods are measured on a scale from 0 to 100. A higher number means a higher glycemic index and indicates an item that will be digested quickly and spike blood sugar. Bread products tend to be higher on the glycemic index scale (Ellis, 2019). Sourdough is a unique bread product because of its lower glycemic index score. In comparison to all other breads, sourdough has the least dramatic effect on blood sugar (Mofidi, 2012). Preventing these spikes in blood sugar is important for diabetics but is something that all of us can benefit from.

If you are intrigued, try out making sourdough for yourself. You will need a sourdough starter to begin. You can make one yourself, I recommend following the guide by The Perfect Loaf. Alternatively, you can ask a friend with a starter if they will share some with you, that way you can bake right away and don’t have to wait for your starter to mature. Once you are ready to go, try recipes from King Arthur Baking and The Perfect Loaf; each have great resources for beginners. I highly recommend trying out sourdough. Even when you know the science involved, it always seems like a little bit of magic occurs when water, flour, and starter turn into a golden loaf of sourdough. 

Image by Brook Kurkjian

References:

1. King Arthur Baking. (n.d.). Sourdough Baking. Retrieved November 10, 2020, from https://www.kingarthurbaking.com/learn/guides/sourdough
2. Ellis, R. (2019). What Is Glycemic Index? Retrieved November 10, 2020, from https://www.eatright.org/food/nutrition/dietary-guidelines-and-myplate/what-is-glycemic-index
3. Mofidi, A., Ferraro, Z. M., Stewart, K. A., Tulk, H. M., Robinson, L. E., Duncan, A. M., & Graham, T. E. (2012). The acute impact of ingestion of sourdough and whole-grain breads on blood glucose, insulin, and incretins in overweight and obese men. Journal of nutrition and metabolism, 2012, 184710. https://doi.org/10.1155/2012/184710