Here’s the link to the article: http://foodmatters.tv/articles-1/you-ll-never-guess-what-veggie-just-beat-kale
And beware the high oxalic acid content of raw greens. As one commenter wrote: “But, I am confused. After being raw vegan off and on for years, I lived on leafy greens in my smoothies, salads etc. I almost lost all my teeth, apparently due to the extremely high oxcalic (sp?) acid”
Cooking greens reduces the oxalic acid. Sadly it also reduces other heat sensitive nutrients like vitamin C.
Being well hydrated and a daily dose of omega-3 fatty acids are also very effective in preventing oxalate deposition.
http://www.cdc.gov/pcd/issues/2014/13_0390.htm#table2_down