Hi Annesse So it turns out that we are on the same page. It sounds like we share very similar or possibly the same diet protocol. My diet is pretty much an organic traditional/paleo diet one. I also agree about the sauerkraut (and other probiiotics) and mentioned this in posts in the Gut/KDM thread last year. I even have Wild Fermentation but have not got around to making any due to the brain fog.!! I agree about pasture raised protein and only eat grass fed beef and pasture raised other protein. Im not sure I agree about supplementation though as any diet, even a traditional or paleo one, is limited by the quality of soil which no longer contains the nutrients and minerals that it did during our ancestors time - even organic pasture. We did evolve to require these nutrients so we need to get them from somewhere (if unavailable via diet) or the engine wont run. So restoring the gut is key, but back to B12. I still have a key question which my absence of knowledge of biochemistry precludes me from understanding and maybe someone (Rich et al) can answer: Q: Is it protease that that enables the B12 to pass the blood brain barrier (BBB)? Or is there another process that is required for this? For me, I have ample serum B12 but it is my functional B12 that is insufficient and I believe I need to get the B12 through the BBB. There are also polymorphisms which would impede conversion and/or availability which cannot be completely rectified by diet alone, imo. If you have 677 polymorphism there is nothing a diet can do to enable the process required to convert the folate to occur. It is broken. I do believe diet/gut issues are key primary areas that need to be addressed. [A change in diet would likely result in epigenetic changes that could go some way to triggering changes to the genetic code. [I believe it is diet and our environment that has resulted in unfavourable epigenetic changes which have resulted in conditions such as CFS, Autism, many autoimmune etc - but that is another story in itself. And can these changes, once made, be reversed ie are the gene marker on/off switches that responsive to more than one change? I have seen a twin study that was very illuminating.] Thank you for sharing your thoughts and I look forward to reading more in your book.