Since the early days of the COVID-19 pandemic, when homemade sourdough starters began bubbling onto kitchen tables around the world, this tangy, chewy bread has achieved near-mythical status. As Taylor Swift confirmed: Sourdough isn't just bread anymore, it's a way of life.
Fans of sourdough say it's easier to digest, better for lowering blood sugar and even good for heart health. But is sourdough bread really a nutritional powerhouse or just a well-fermented fad?
What makes sourdough different?
Unlike a regular sandwich loaf, which relies on the addition of commercial yeast, a true sourdough starter uses wild yeast. Wild yeast includes microorganisms from the air and flour that naturally ferment over several days. This slow process not only gives the sourdough its distinctive flavor, but also changes the chemical composition of the bread.
During fermentation, lactic acid bacteria and yeast work together to predigest some of the starch and proteins in the flour, according to the Cleveland Clinic. This process can lower the bread's glycemic index, meaning it may not raise your blood sugar as quickly as white bread. A typical slice of white bread has a glycemic index of 100, while sourdough is closer to 55. That's one reason why some nutritionists consider it a better choice for people watching their blood sugar.
These same bacteria also extend the shelf life of the starter by preventing microbial spoilage, an ancient form of natural food preservation that predates refrigeration.
Read more: What is the difference between sourdough and yeast?
What are the potential health benefits of sourdough?
Leaven fermentation process has been associated with some promising health markers.
Research in Nutrients found that “participants who replaced their regular bread with sourdough for two months showed lower levels of sICAM, an adhesion molecule essential for the development of atherosclerosis.” In other words, eating sourdough may help reduce inflammation of the arteries, which can lead to heart disease.
The researchers also observed a “decrease in diastolic pressure,” suggesting that the starter may have a mild antihypertensive effect.
This effect may be due to the release of bioactive peptides during long-term fermentation of the starter. These compounds can inhibit angiotensin-converting enzyme (ACE), which helps control blood pressure by constricting blood vessels. Some scientists believe future research could even examine genetic variations in ACEs to personalize sourdough recommendations for people with high blood pressure.
But before declaring sourdough as the next superfood, the authors of one study noted that “despite minor fluctuations in blood pressure, we did not observe any additional differences in lipid or glucose metabolism after the two-month intervention.”
What's wrong with the hype around sourdough?
Despite all the glowing social media posts and health blogs touting sourdough's superpowers, the truth is more complex. Although chemical and laboratory studies show potential benefit, clinical data (studies in humans) remain limited and conflicting.
According to research in Dietary boundaries “To date, limited and inconclusive clinical evidence on the health benefits of sourdough bread has also prevented the approval of health claims by regulatory authorities, including the European Food Safety Authority (EFSA). Despite the apparently favorable data, EFSA has not yet approved any of the requested health claims for sourdough bread.”
Sourdough bread could be simpler blood sugar and digestion than its commercial counterparts, and it may even offer small cardiovascular benefits, but it is not a magic bullet. For now, the biggest benefits of sourdough may be more emotional than biochemical: the satisfaction of growing something alive, watching it grow, and sharing it warm from the oven.
This article does not contain medical advice and should be used for informational purposes only.
Read more: Sour, salty and fermented: here's how sauerkraut supports gut health
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