Anyways, I found it quite interesting that while reading through Jack Kruse's new book, "Epi-Paleo Rx," I came across this passage.
If you get a lot of brain freezes when you drink cold things this might signal you suffer from a high tissue omega six level.
This was the first time I've ever come across a nutritional reasoning behind the so called brain freezes.
Omega 6 to Omega 3 ratio for modern man is pretty horrific in terms of what is suggested. Most paleo or nutritional guidelines shoot for 1/1 ratio. It is estimated that a grain heavy diet is somewhere between 20/1 and for real poor nutrition 40/1. A ratio of even 6/1 can provide a lot of health benefits. This is why supplementing with quality fish oil (EPA/DHA) often provides amazing results for a myriad of different health issues. Also, why decreasing the bread based/fried foods also increases health. Perhaps, getting rid of brain freezes is another side benefit.