I confess, my research about iodine was rather frustrating. It's quite a multi-faceted topic. I'll share some articles that go more in depth, but here I'll try to keep it as simple as possible.
1) Amount of Iodine needed -
The Recommended Daily Allowance (RDA) for Iodine in the USA is 150 micrograms/day (or over 200 mcg for pregnant/nursing women). However, many people in Japan regularly consume over 13 milligrams (or 13,000 micrograms). So there is debate among health proponents about how much iodine we actually need...is it 150 micrograms? or 6-12 milligrams? That's quite a drastic difference.
My thought is that each body probably varies in how much iodine it needs. If you've been iodine deficient, you might need higher levels for a short period of time in order to build up once again. Then you could probably maintain with a lower level. I think the best thing is to consult with a trusted health provider and possibly do a simple test to see if you are iodine deficient and need more iodine in your diet. (Generally speaking the articles I read did not recommend iodine supplements, as having too much iodine in the body can also cause problems.)
2) Natural sources of iodine -
I found several foods listed as sources of iodine, some with higher amounts than others.
Some foods with the higher amounts of iodine seem to be cranberries and organic raw milk products - milk, cheese, and yogurt. (Note: I don't recommend eating processed dairy products as they are full of hormones, antibiotics, and all kinds of toxins. If you consume dairy make sure it's organic and raw if possible.)
Eggs, strawberries, and navy beans also contain iodine in medium amounts.
A few foods with lesser amounts of iodine, but still some, are bananas, green beans, and dried prunes.
One article listed onions, garlic, pineapple, and artichokes as sources of iodine (however I didn't see those listed other places, so I don't know how much iodine they contain.)
Theoretically, if you're eating himalayan salt plus plenty of fresh, healthy foods, including the ones listed above, you may be able to maintain a healthy amount of iodine. Though again, it's probably best to work with a health provider to assess your specific level of iodine need.
Also, I should mention that seaweed and sea vegetables contain high amounts of iodine. However, it's difficult to find a product that is organic and not contaminated with toxins, since the oceans have become so polluted. But if you find a reputable source of organic kelp or seaweed, that could also be a good way for you to add iodine.
3) Avoiding Iodine deficiency -
This article from Dr. Mercola covers the whole topic of iodine. He also explains how bromine exposure replaces iodine in the body and leads to iodine deficiency. So one way to avoid iodine deficiency is to avoid exposure to bromine (which is in baked goods, plastic, soft drinks, medications, pesticides, etc.). If you're eating healthy, organic foods, drinking pure water, and living as chemical-free as possible, you will limit your exposure to bromine, and hopefully avoid its negative effects.
As I said, this is a complex issue. Iodine is something our bodies vitally need, but it's not a simple matter of taking an iodine pill every day. It's important to assess how much iodine your body needs and then figure out a plan that works for you.
Personally, so far I'm really enjoying the Himalayan salt (great flavor and good source of trace minerals), but I'm still trying to figure out how to get enough iodine. I've been experimenting with using half himalayan salt and half iodized sea salt. But that's a lot of salt to get down in one day...so I'm still working on it.
I hope these thoughts have been helpful. If you have an information to add, please share it with us in the comments.