All,
http://opinionator.blogs.nytimes.com/20 ... ead/?_r=1&Teaching us once again that just because a little is good, doesn't mean a lot is better.
FWIW, this is true of all vegetables (that is, leaves/roots/stems/flowers). One of the defense mechanisms which plants develop to keep from being eaten to the ground is slow poisons and vitamin blockers. Raw spinach, for example, blocks your absorption of calcium. This isn't a problem for normal consumption amounts, but folks getting into juicing can fairly easily dose themselves with 5kg of spinach or kale a week.
Also, in most cases, cooking eliminates these unhealthful effects, which makes you wonder what the Raw Foods people are thinking?