Originally Answered: Authoritative answer needed. Is Sea Salt truly more healthful than conventional salt?
What we call salt is sodium chloride (NaCl). Sea salt is obtained by evaporating sea water, and it may contain traces of ions like magnesium and potassium, in addition to the sodium and chloride ions which the main constituents. Once I was housesitting for some people and they had sea salt in their pantry that had a pretty long list of trace minerals. If I remember correctly it was 99% sodium chloride and the other 1% was made up of five to ten other minerals. Most other table salt is obtained from halite minerals found on land. It is usually fortified with iodide which is necessary for proper thyroid function, and in some countries (but not in the US) it is not uncommon to find added fluoride, for strong teeth. Potassium chloride (KCl) is a completely different entity which is sometimes used as a salt substitute for people concerned about consuming excess sodium. Sea salt is not potassium chloride.
Sea salt, rock salt, Kosher salt and table salt are essentially chemically identical and behave the same way in the body. Sodium chloride is highly soluble in water and does not clump together in the body. It dissolves readily in tap water, saliva, gastric juice and inside of our cells. Salt does not clump together and accumulate in the body. Any negative health effects attributed to salt are due to its sodium content, which is the same no matter where the salt comes from, because table salt, by definition, is sodium chloride.
In theory, it is possible that you might gain some benefit from the trace minerals found in certain sea salts, but most Americans do not have serious micronutrient deficiencies so it is unlikely that the vanishingly small quantities of, let's say, selenium, found in a particular brand of sea salt would have a serious positive impact on your health. It sounds like you are mindful of your health and watch your diet, so you probably have less to worry about than the average American. Interestingly, since sea salt is not usually fortified with iodide, you may be actually be missing out on some extra nutrition.
"Organic" in this context refers to how food is handled and processed, so one could just as easily make organic table salt as any other type of salt. Call me cynical, but my hunch is that many organic food producers use—and advertise their usage of—sea salt to capitalize on the assumption their customers make that sea salt is somehow more natural and therefore better than salt which is mined from rocks on dry ground.
Some cooks to prefer sea salt or Kosher salt to regular table salt, but this is because of the size of the salt grains and not because of any health or chemical differences. It all dissolves rapidly in your mouth and stomach and behaves the same way in your body.