Vegetables are rich in many vitamins, mineral components, antioxidants, and macronutrients. However, they also contain high levels of anti-nutrients, which reduce the bioavailability of some nutritionally essential components such as zinc or iron. The processing of vegetables, including microbial fermentation, reduces or neutralizes tannins and phytates, which results in greater bioavailability of vitamins and minerals.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10051273/
