whose recommended daily dose? The FDA's? Before you buy into what the FDA is selling, learn who they work for (ie big pharma) and how they make their decisions.
The normal amount of Iodine
needed to MAINTAIN Iodine
sufficiency is estimated approx 6-12mg BUT you have to reach sufficiency first which means taking a lot more than is needed for maintenance. If you just take 6mg a day and your body uses 12mg a day you will NEVER reach sufficiency. You need to take more than your body uses daily to give it what it needs to function and a surpluse to build up stores. Then once sufficiency is reached you can cut back to what you need daily. For some 6mg may be enough, but not for others.
Thats the primary reason you see people taking so much. Another reason is to overcome halide toxicity. If you have other halides competing at the receptor level with Iodine
you may need more iodine to increase the odds of the iodine you do take getting to the receptor and doing its job.