Brazil nut as a mood booster (Why ? Selenium )

Info source: http://seattletimes.com/html/health/2003573688_foodmood18.html

Brazil nuts: One brazil nut will give you all the selenium you need to elevate your mood. Studies conducted on this trace mineral found study participants' moods brightened considerably when they got enough selenium. Don't feast on brazil nuts with the idea that more is better, because selenium can be toxic. Additional sources of selenium are tuna, whole-grain cereals and swordfish.