Sourdough bread is naturally-leavened. Rather than relying on commercial or instant yeast like most bread, sourdough baking utilizes a living culture or ‘sourdough starter’ as a rising agent. A sourdough starter is full of several strains of beneficial bacteria or probiotics and wild yeast, including lactobacillus. When active sourdough starter is mixed with flour and water to create dough, the healthy bacteria and yeast feed on the flour, converting it to lactic acid and carbon dioxide.
Lacto-fermentation is what gives sourdough bread air pockets, a fluffy texture, and a slightly tangy flavor. However, most homemade sourdough bread isn’t all that sour-tasting at all! It is simply called ‘sourdough’ because it is fermented. And the simple fact that it is fermented is why sourdough bread is better for you. Rise and flavor aside, lactic acid bacteria causes numerous beneficial changes to the nutrients, gluten, and other compounds found in sourdough.
Not all sourdough is created equal.
The process of making sourdough is not an exact science. Except in a laboratory or factory-like setting, no two loaves are the same! Many variables exist: the kind of flour used, the strain of beneficial bacteria and yeasts living in the sourdough starter culture, and also each baker’s routine. Some dough ferments for an extended period of time, and others for only a couple of hours. Factors such as temperature and humidity also influence the fermentation process.
Keep in mind that not all bread marketed as ‘sourdough’ has gone through a traditional long fermentation process. Most grocery store sourdough utilizes instant yeast instead of a natural sourdough starter culture, has been artificially flavored to taste sour, and also contains preservatives and additional ingredients. Artisan (small bakery) or homemade sourdough promises the most nutritional value.
Does sourdough contain gluten?
While sourdough isn’t considered entirely ‘gluten-free’, it does contain far less gluten than unfermented bread and average wheat products
Gluten degradation & digestive issues
In an unfermented state, the gluten and other carbohydrates in wheat or rye grains are indigestible to some people. In response, the person experiences bloating, gas, pain, or other uncomfortable symptoms. (Been there, done that!) The associated gut inflammation also prevents the absorption of other essential nutrients, taking away from general well-being.
Repeated studies show that lactic acid bacteria fermentation of wheat and rye sourdough modifies the molecular structure and/or reduces certain carbohydrates and proteins – including gluten. The resulting sourdough is easier to digest and triggers fewer unpleasant reactions. In general, the longer sourdough is allowed to ferment, the more gluten is degraded and reduced.
As the fermentation process degrades gluten in sourdough, many other natural compounds are enhanced or created. Here is an impressive, science-backed list of why sourdough is healthier than other bread:
One study showed that naturally fermented wheat or rye sourdough contained 10 to 17 times the amount of leucine and isoleucine than non-fermented bread. Leucine and isoleucine are both branch chain amino acids (BCAAs). These are two of the nine essential amino acids that are critical to our health, but aren’t synthesized by our bodies. Meaning, they must be obtained through diet alone. BCAAs are often found in protein-rich foods like dairy, meat, and eggs. Or, in dietary supplements like whey or soy protein powders. BCAAs promote strong healthy muscle growth, reduces muscle wasting, and eases muscle soreness.
Lower glycemic index
The elevated concentration of branched chain amino acids (described above) in sourdough also reduces post-meal blood glucose levels by stimulating insulin response. Combined with the fact that sourdough bread is digested more slowly than other bread, people experience a significantly lower glycemic response (or less of a blood sugar spike) after eating sourdough. People also report feeling full or more satiated for a longer period after eating sourdough than basic bread. The result is a reduced risk for insulin resistance, weight gain, and diabetes.
A 2018 scientific report published by Nature Research showed a notable increase in the concentration of 28 different peptides in fermented sourdough. Nearly all of these peptides (short chain amino acids) have known antioxidant or antihypertensive properties. They help reduce free radicals in the body and reduce blood pressure (respectively), providing protection against cancer, stroke, and heart disease.
Less Phytic Acid, Increased Mineral Bioavailability
Grains and legumes contain a natural substance called phytic acid. While phytic acid does have a few health benefits, it also gets a bad rap as an ‘anti-nutrient’. Phytic acid inhibits the absorption of iron, calcium, and zinc, which can lead to mineral deficiencies. Some naturopaths also suspect that phytic acid can exacerbate Irritable Bowel Syndrome symptoms such as bloating and gas. Once again, fermentation to the rescue!
Research shows that sourdough that has undergone a long, slow fermentation process ‘pre-digests’ and partially neutralizes phytic acid. Therefore, we can more easily digest the bread – and better absorb the minerals that it contains!
Improved Gut Health & Nutrient Absorption
Thus far, we’ve explored how fermenting sourdough can increase or decrease certain compounds, but how about how our bodies react to them?
To start, if you’re someone who experiences unpleasant side effects from non-fermented bread but have continued to consume it anyway, you’re not doing your body any favors. The bread itself is less nutritious than sourdough, and the constant irritation and inflammation in your bowels can inhibit you from fully absorbing all the nutrients you consume – not just those in the bread!
Like all fermented foods, sourdough promotes general gut health and creates a favorable environment for maximum nutrient metabolism. A healthy gut directly contributes to maintaining a healthy immune system, digestive system, and overall total-body health! During sourdough fermentation, beneficial bacteria and yeast give our gut a jump start and ‘pre-digest’ a lot of compounds, making them more bioavailable to our bodies. Fiber is just one excellent example.
Traditionally fermented sourdough is healthier than standard non-fermented bread, for the following reasons:
• Consuming sourdough triggers less of a post-meal blood sugar spike than other bread, which can protect against insulin resistance, weight gain, and diabetes.
• Sourdough contains less gluten than non-fermented bread, and therefore triggers less inflammation, bloating, pain, or other common side effects to gluten-sensitive individuals.
• Increased amino acid concentrations in sourdough contribute to healthy muscles, and help reduce the risk of stroke, cancer, and heart disease.
• Fermented foods promote a healthy gut biome and improved nutrient bioavailability. The reduction of phytic acid (an ‘anti-nutrient’) leads to better mineral and nutrient absorption.
• Homemade sourdough is healthier than store-brought bread because it is more fresh, less processed, contains no artificial additives, and creates less waste. It is also fun and easy to make!