There is no point in taking iodine as a precautionary measure to prevent against radiation exposure after a leak or attack on a nuclear power plant.

The thyroid only stores iodine for a limited amount of time. And taking too much iodine — even the good stuff — can be dangerous.

But the iodine is still only effective if taken when it is needed. Experts say an iodine "block" only has a chance of helping if the good iodine is taken just before or during contact with radioactive iodine. 

• Our bodies do not produce iodine themselves. But we do need it, so we consume iodine through food or supplements.
• When consumed, the iodine is collected or stored in the thyroid gland, where it is used to produce hormones. They help various bodily functions and even support the devel...