Ever since I became aware that the foods of the diet we're designed to eat do not necessarily contain enough of all the nutrients our bodies need for optimum functioning (because of the way they're grown), once I was finished with researching the two problematic non-food-provided nutrients (B12 & D), I started drilling down into the list of the nutrients that food is supposed to provide, and the one that stuck out like a sore thumb was iodine. And it has now been added to my list of "problematic nutrients".
The reason it has such a huge impact is three-fold: 1. we aren't aware of it like we're aware of the issues with B12 and D, 2. lack of sufficient iodine is a contributing factor in so many ill-health conditions (both noticeable and as-of-yet unnoticed), and 3. a lot more people are low in iodine than B12 and D to the point where it's having a physiological effect on them (and that includes cognitive function and weight management).
Iodine is required for so many physiological processes that it would blow your mind. As the resident iodine literate health practitioner I find myself on an actual quest to get this message out to the general public and especially to those whose goal is to have the best health their DNA will allow them to have.
I've recently been interviewed on this subject by three well-respected folks, and when those hit the net I'll let you know. But for now, please pour over my main iodine article at http://health101.org/iodine
Based on those I've been doing problematic nutrient testing and counseling with - including raw foodists - I can say with a high degree of certainty that just about everyone reading this would benefit from adding the iodine issue into their learning journey.