My wife and I were debating the inclusion of the stems of some kale in a lovely dish tonight (Kale, Burdock, and Shitakes sauteed with Garlic and braised with Mirin and Tamari) and she (the pro-stem) faction said they were the most nutritious part of the vegetable. When pressed, she admitted she had no idea where she heard this, and suspected it was based on the logic that peels are supposed to be the most nutritious part of the potato. The we started wondering what the truth is.
So, I'm wondering if anyone here can help - Are the stems the most nutritious part of kale? Of collards? Of other greens? Are the peels/skins really the most nutritious part of potatos or yams? What about carrots and other roots? What do you lose when you peel them?
Please, fill me in on what you know and how you know it.