Phil,
I don’t think there is any magic in “special” foods. Food is either biologically appropriate for us or it is not. My gut feeling is that most of these special foods became special through filling some immediate need but then carried on through tradition long after the need passed, often taking on mystical importance. Just look at the way some people worship pemmican as some sort of wonder food.
I imagine that most of these foods were eaten when the normal food supply was scarce, or was the result of attempting to store food over the long term, and over time these foods became embedded in the culture. Along comes some researcher (Weston Price et. al.) and they find that each culture has among its traditions some special food that is ascribed magical powers – the real reason for having started consuming these foods long lost in antiquity.
Of course this is just my own opinion, but I see this sort of thing happening all around me today. Pemmican is one example, and you can look at much of what AV does (not to mention the host of other dietary gurus) and see the roots of one food or another taking on mystical importance with little evidence supporting the magical claims. It seems to be human nature to want to believe in mystical magical things and there is no shortage of those willing to fill this basic human need. When the guru touting this stuff is gone, tradition takes over until it is deeply imbedded in the culture.
Some modern examples:
Wheat grass, green juice, cranberry juice, coral calcium, ionized water, high meat, vitamin supplements, red and purple vegetable juice, coconut oil, CoQ10, triple distilled fish oil, yogurt, pro-biotics, tofu, & etc. There’s plenty of special foods ascribed with magical powers. At best, some may provide a benefit if eating an inappropriate diet in the first place, and at worst I expect many are modern day snake oil and possibly down right harmful.
Now grubs, that's real food!
Lex