When I was a kid, which was a long time ago, I loved to watch black and white cartoons of Popeye the Sailor. Whenever Popeye was faced with a desperate situation, he'd pull out a can of spinach, pop it open with his remaining strength, and then he'd find his superpowers to win the day. "I'm strong to the finich (finish) 'cause I eat my spinach," he'd sing just before "The End" flashed on the screen and the credits would start to roll.
Scientists at the Karolinska Institute in Stockholm haven't found that spinach gives diabetics superpowers, but
they have found that the nitrates in spinach help cells function better under conditions of oxygen deprivation. Feeding volunteers 200 to 300 grams of spinach a day (that's about 1/2 to 2/3 pound, and its a lot) decreased oxygen needs during exercise.
And the significance to diabetics is that when cells burn sugar under low-oxygen conditions, they burn up to 35 times more. At least for a short time.
As you'll read on this site over and over again, test it out. See if eating more spinach helps you lower your blood sugars. And do let us know if you develop superpowers.
Dietary inorganic nitrate improves mitochondrial efficiency in humans, Filip J Larsen, Tomas A Schiffer, Sara Borniquel, Cell Metabolism, 2 February 2011.