The list is getting a bit ridiculous, but selenium is another thyroid booster. A study of French women showed the less selenium they obtained, the bigger their thyroid gland was (not a good thing). It also boosts immunity and helps fight cancer. You should be able to get iodine and selenium from vegetables, but modern soil tends to be depleted. I’m not even sure where you can get selenium now apart from Brazil nuts. Certain minerals, thyroid function and susceptibility to infections seem to be closely related. I’ve even seen some candida success stories on CureZone involving these minerals.
Apparently, your thyroid can react to iodine in too high a dose, but will adjust to it over time. It’s best to start small, with say the RDA, watch for any reactions and then gradually increase the dose. Toxicity hasn’t been observed even in ridiculously high doses, but you shouldn’t get carried away with it.
400mg of magnesium is the RDA and a decent amount to take (for once). It’s poorly absorbed after that sort of level, so there’s no benefit in going above it. Apparently the threshold level for women is slightly lower, so try breaking the tablet if you get any bowel reactions to 400mg.