There is absolutely nothing like a thick slice of toasted sourdough bread... it leaves you feeling full and satisfied without the heaviness (and regret!) of processed foods. But let's talk about the actual science behind why it makes you feel good... Hint: it's time, or the long process of fermentation and the thriving ecosystem that is your sourdough starter! Let's talk more about it!
A Buffet for "Good Bacteria"
After years of baking, and the research that inherently goes along with it, I have learned a lot about fermentation. While your sourdough starter is teeming with live lactic acid bacteria (LAB), these microbes don't survive the high heat of the oven when the dough is baked. The slow fermentation process, and the presence of a wild ecosystem consisting of bacteria and yeasts, modifies the carbohydrates and fibre from the wheat, creating resistant starch and soluble fibres. These then act as fuel for the good bacteria already living in your gut, helping them to thrive. Commercial yeast simply cannot do this... not only is it a monoculture, it was created for one purpose: speed! These two factors mean that it cannot alter the carbohydrate and fibre structure of flour like sourdough can.
Breaking down the "Hard to digest" bits
Beyond feeding the healthy gut bacteria, the slow fermentation of sourdough helps to break down the phytates (phytic acid).
Phytic acid, a compound found naturally in grains, is often called the "anti-nutrient" because it binds to healthy minerals like iron, zinc, and magnesium - ultimately preventing your body from being able to absorb them. The acidity produced during the long fermentation process activates an enzyme (phytase), which breaks down the bonds to these minerals, making them more bioavailable for absorption.
Sourdough and Glycemic Index
What is the Glycemic Index? It is a ranking system that measures how quickly carb-containing foods raise the blood sugar. Low Glycemic Index diets decrease the risk of developing Type II Diabetes, help to control your blood sugar, and decrease the risk of developing heart disease and stroke
Clinical trials have shown that sourdough has a significantly lower Glycemic Index than commercial white bread. White bread has a high glycemic index because it is digested quickly and causes rapid spikes in blood sugar. Similarly, highly processed foods have high glycemic indices.
The acids produced during the long fermentation process (Lactic and acetic acid) slow down the rate at which the body absorbs starches. This leads to a steadier release of glucose into your blood stream, better managing your blood sugar over longer periods of time.
More than just for the body...
Ultimately, the magic of sourdough lies the time it takes to make it. Beyond the long list of physical health benefits, sourdough allows you to slow down and connect with the process and the food you're making. In a world of instant gratification and low attention spans, making a loaf from scratch provides a deep sense of satisfaction, joy, and pride.