What it is
A fermented food with centuries of continuous use — microbes doing the preserving, pre-digesting, and flavor work.
Why your biology objects
Fermentation breaks down the anti-nutrients and pre-digests the food — natto and tempeh neutralize soy's phytates, sourdough's phytase frees the grain's minerals — while seeding live cultures and vitamin K2 (natto is the richest source). This is the technology the additive aisle keeps trying to imitate.