What is the Difference Between Potassium Iodide and Potassium Iodate?

Potassium iodide and potassium iodate are both forms of iodine that can be used for dietary supplements and radiation protection. However, there are some differences between the two:

1. Stability: Potassium iodate is less soluble and more stable than potassium iodide, making it preferred for tropical moist conditions. Potassium iodide has a poor shelf life in hot and humid climates due to hydrolytic loss of iodine vapors.
2. Effectiveness: Potassium iodide is superior in terms of effectiveness because it breaks down and is absorbed by the body much faster and more thoroughly compared to potassium iodate. The US National Council on Radiation Protection and the US FDA have recommended potassium iodide over potassium iodate based on factors such as the degree of blocking achieved, the rapidity of onset of the blocking effect, the duration of the blocking effect, and the safety of the blocking agent.
3. Oxidative Damage: Potassium iodide has been suggested to prevent oxidative damage to membrane lipids in the thyroid gland, while potassium iodate does not possess any direct beneficial effects on oxidative damage to membrane.
4. Shelf Life: Potassium iodate has a longer shelf life compared to potassium iodide.
5. Bioavailability: Human iodine bioavailability from potassium iodide is higher than from potassium iodate.

In summary, potassium iodide is generally preferred over potassium iodate due to its superior effectiveness, faster absorption, and lower risk of oxidative damage. However, potassium iodate may be more suitable for use in tropical moist conditions due to its greater stability.

Comparative Table: Potassium Iodide vs Potassium Iodate

Here is a table comparing the differences between potassium iodide and potassium iodate:

Potassium iodide (KI) and potassium iodate (KIO3) are both used to protect the thyroid gland from the effects of radioactive iodine, which can be present in water and food after a nuclear event and accumulate in the thyroid, causing thyroid cancer. However, potassium iodide is less effective in blocking radiation compared to potassium iodate and has a shorter shelf life in hot and humid conditions. On the other hand, potassium iodate has a longer shelf life in hot and humid conditions but is more likely to cause side effects, such as intestinal irritation.