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Vitamin B12 is known to be essential for a healthy brain and nervous system. It turns out, it’s also needed by beneficial gut bacteria that help the human body maintain overall good health. Scientists at the Department of Energy’s Pacific Northwest National Laboratory have found that even though some gut microbes make B12, it’s a labor- intensive process, and short supplies can disrupt DNA and growth of vital microbial communities. Probiotics are normally viewed as the go-to supplement for healthy gut bacteria, but now we know that B12 also plays an important role.