Many people assume that commercial bread is hard to digest simply because it’s not fermented like traditional sourdough. But there may be more to the story.
Some researchers and holistic practitioners have raised concerns about the actual strain of commercial baker’s yeast used in modern breadmaking. Unlike the wild yeast and bacteria found in a natural sourdough culture, commercial yeast is a single species (Saccharomyces cerevisiae), isolated and selected for speed, consistency, and volume. It’s designed to rise fast and produce predictable results, not necessarily to support health.
While there isn’t a confirmed link between commercial yeast and direct toxin production like mold-based mycotoxins, some studies do suggest that different yeast strains can influence the chemistry of the bread in ways that may affect the gut. Certain strains of yeast and bacteria used in food fermentation have been shown to produce or reduce bioactive compounds, depending on the environment and the fermentation process. But in standard industrial bread production, there is little time for any fermentation at all.
Modern breadmaking methods often skip long fermentation entirely, relying instead on techniques like the Chorleywood Bread Process, which uses rapid mixing, added gluten, and extra yeast. This not only affects texture and flavor but also leaves more phytic acid in the bread. Phytic acid blocks mineral absorption in the gut, making bread less nourishing and harder to digest.
There’s also the issue of shelf life. Commercial breads are often loaded with preservatives and mold inhibitors, but ironically, they can still go moldy faster than sourdough. That’s because sourdough’s natural acids help preserve the bread and prevent spoilage without synthetic additives.
Some online claims suggest commercial yeast acts aggressively, producing unwanted by-products or behaving in ways similar to harmful fungi. While these comparisons aren’t backed by strong evidence in current research, it’s worth noting that almost all traditional cultures used fermented or naturally leavened bread for thousands of years before isolated commercial yeast ever existed.
And it wasn’t just a food choice. In many ancient cultures, bread was a staple food and a key source of nourishment. Even biblical references show how central bread was to daily life.
The takeaway? Whether or not commercial yeast is harmful on its own, the real issue is the loss of time, tradition, and natural fermentation. Sourdough isn’t just a trend – it’s a return to bread that works with your body, not against it.