I did some reading about this a few years back. TLDR: Vitamin B complex is insanely abundant in nature, for example, an 8 ounce glass of pond water in north america typically contains 200x+ your daily vit B requirements. Water sanitization is a good thing that we need badly. However, it does remove the vitamin B. For a long time people have gotten their bit B from meat, because farm animals drank pond water/lived outside. Do you see where I'm going with this? Basically, our meat supply is failing to provide people with the vitamin B they need because of industrialization and meat not being the best vitamin B delivery method. My GP told me that most Americans are low in B complex and should go the way of the vegans and supplement. She's right, I feel so much better. All it takes is a few drops of b complex in my morning glass of water. It's a shame more people haven't figured it out yet.