Nitric Oxide is a gas that's naturally produced in the body, it's used to communicate between cells.
I read about N.O. when I first discovered my son had sickle cell disease but I never researched it any further, now, I ran across a video explaining the importance of it and sickle cell and how N.O. can help minimize crisis. There are certain foods that contains N.O. like Collard greens, spinach, seafood and much more. Please see video and article below.
Vitamin C and E have properties that can improve and help sustain Nitric Oxide levels
Article on Nitric Oxide
http://www.healtharticles101.com/top-10-nitric-oxide-foods/
Video on Nitric Oxide