Health

The complexity of a molecule of wheat starch is a chain of tens of thousands of saccharide links (typically 30,000–40,000). For comparison, cotton cellulose contains around 2,500 saccharide units per chain—making wheat starch more than ten times as complex.[1] It is very similar to cellulose (wood fiber) and is too dense for humans to digest. Likewise, gluten is a complex, long-chain protein molecule that is difficult to digest.

Commercial bread uses significantly more yeast—in some cases, thousands of times more—along with various additives to accelerate CO2 production.[2] However, this process often leaves the dough effectively unfermented. Bread (specifically Real or Sourdough bread) is substantially different from modern commercial bread, sometimes referred to as "fake bread," which is baked quickly using commercial processes optimized for speed, profit, and efficiency rather than for health.

What differentiates sourdough bread is that it is naturally fermented. During this natural fermentation process, the microflora in the culture begins to break down (pre-digest) the carbohydrates and proteins present in the dough. A second biological process benefiting sourdough bread is called autolyse, in which enzymes (amylase and protease) in the flour begin breaking down starch and gluten, improving digestibility, flavor, and health. Additionally, as the bread cools after baking, a phenomenon called starch retrogradation occurs—where gelatinized starches begin to realign and recrystallize. In sourdough, this process is slower and more stable due to the acidity, making the resulting starches more resistant to digestion and further lowering the glycemic impact.

Additionally, wheat contains phytic acid and lectins. These are natural preservatives, but like most preservatives (natural or synthetic), they are not beneficial to health and are considered anti-nutrients. Lectins have been linked to digestive issues and irritable bowel syndrome (IBS).[3] Both phytic acid and lectins are significantly reduced or eliminated during the sourdough fermentation process.[4]

Sourdough bread is high in natural sour flavors (specifically acetic acid and lactic acid) and fiber. Studies have shown that both acid and fiber contribute to a significantly lower glycemic response. One study published in the British Journal of Nutrition found that sourdough bread made with whole grain wheat resulted in a lower postprandial blood glucose and insulin response than bread made with baker's yeast.[5] Additionally, a friend of mine who wears a continuous glucose monitor (CGM) regularly sees a 30–40 point increase in blood sugar after eating a serving of commercial bread. After eating a serving of my sourdough, his blood sugar rises only 4–5 points.

Sourdough bread is naturally fat-free, high in fiber, and balanced in protein. It has been a dietary foundation of Western Civilization for centuries.

Footnotes:

[1] Starch Structure: McCleary, B. V., & Monaghan, D. A. (2002). Measurement of Resistant Starch. Journal of AOAC International, 85(3), 665–675.

[2] Poutanen, K., Flander, L., & Katina, K. (2009). Sourdough and cereal fermentation in a nutritional perspective. Food Microbiology, 26(7), 693–700.

[3] Liener, I. E. (1994). Implications of antinutritional components in soybean foods. Critical Reviews in Food Science and Nutrition, 34(1), 31–67.

[4] Lopez, H. W., Leenhardt, F., Coudray, C., & Remesy, C. (2002). Minerals and phytic acid interactions: Is it a real problem for human nutrition? International Journal of Food Science and Technology, 37(7), 727–749.

[5] Scazzina, F., Del Rio, D., Pellegrini, N., & Brighenti, F. (2009). Sourdough bread made from whole wheat flour improves postprandial glycemic and insulin responses in subjects with normal glucose tolerance. British Journal of Nutrition, 102(7), 850–853.