And B12 is found in soil bacteria, which before our filtered and cleaned food supply, would probably have usually found its way into our guts. Source: https://

And B12 is found in soil bacteria, which before our filtered and cleaned food supply, would probably have usually found its way into our guts. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4765460/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4765460/