Biochemical Research

https://www.health.harvard.edu/healthbeat/the-gut-brain-connection

https://draxe.com/gut-brain-connection/

https://www.scientificamerican.com/article/gut-second-brain/

http://www.nytimes.com/2013/05/26/opinion/sunday/breeding-the-nutrition-out-of-our-food.html?pagewanted=all&_r=2&

http://theweek.com/articles/459143/peak-soil-why-nutrition-disappearing-from-food