To increase nitric oxide, Eat more L-Arginine and L-Citrulline Amino Acids -

http://consciouslifenews.com/4-ways-increase-nitric-oxide-naturally-better-workout-sex-heart-health/1155434/

Eat more L-Arginine and L-Citrulline Amino Acids - 

Nuts and fruits are the best vegetarian sources of these amino acids, but they also exist in meat and dairy. However, the antioxidants in fruits and nuts also protect the nitric oxide that is created by eating these foods. Citrulline is recycled into L-arginine, which then produces more nitric oxide. and L-Citrulline Amino Acids - 

Nuts and fruits are the best vegetarian sources of these amino acids, but they also exist in meat and dairy. 

However, the antioxidants in fruits and nuts also protect the nitric oxide that is created by eating these foods. 

Citrulline is recycled into L-arginine, which then produces more nitric oxide.