Very interesting. You know I always wondered about beets, they just look so nutritious, but they claim they are not as full of vitamins as they look. I knew they had to be good for something! Very compelling! Beets are one of those things that are often GMO's. So, I always buy organic seeds. Cold beets, spinach leaves and feta cheese- heaven!
Don't know how much cooking changes the nitrites, but take beets that have been boiled enough to take the skins off, slice or chunk into bite size, boil in apple juice until a lot of the juice is boiled down, turn the heat way down, add cider or wine vinegar and honey, and cook a while. Be careful adding the honey and vinegar because mine quickly boiled over. Made a mess.