There's a new deficiency thats going unoticed in todays society, that may be the lack of Iodine in our diet,
Here's a good article on the concerns that are being made due to changes in food production and normals.
Diets that are extremly high in iodine have the lowest breast cancers and weight problems.
IE Japan where they consume about 14 mg of iodine daily in the form of KELP ,the US reccomended amount 120mcg which is about .012 mg .
SO there be some confusion about RDA.