From: Sea salt: Is it better for you than regular salt? - MayoClinic.com
"Sea salt and table salt have the same nutritional value. The real differences between sea salt and table salt are in their taste and texture.
Sea salt is harvested from seawater through evaporation. Table salt is typically from rock salt, which is mined from mineral deposits. Both types of salt can be fully refined, and the end result is pure sodium chloride. Variations in the refining process result in different forms of salt.
Table salt is a fine-grained salt that often contains added iodine (iodized salt). Iodine is necessary for normal thyroid function. Some table salt may also contain anti-caking ingredient.
Sea salt is available in fine or coarse grain. Sea salt has a slightly different taste than table salt because of different minerals it contains. Many people prefer sea salt to table salt because they claim it has a more subtle flavor. Sea salt doesn't contain iodine or any other additives. However, if you use sea salt you typically don't have to worry about not getting enough iodine in your diet because iodine is available in many other foods, including dairy products, seafood and many processed foods.
If you favor foods with fewer additives, you may prefer sea salt. But there's no evidence that the additives in table salt are harmful to your health. Although your body needs some sodium to function properly, most people eat too much, which can lead to high blood pressure. Whether you use sea salt, table salt or some other type of salt, most experts recommend between 1,500 and 2,300 milligrams of sodium a day for healthy adults."