I did a little research on MSG. You may be right about labeling. It seems it occurs naturally in many foods and is added in many under numerous names and forms.
“The FDA considers labels such as “No MSG” or “No Added MSG” to be misleading if the food contains ingredients that are sources of free glutamate, such as hydrolyzed protein. In 1993, the FDA proposed adding the phrase “(contains glutamate)” to the common or usual names of certain protein hydrolysates that contain substantial amounts of glutamate”
“Even in my youth people with large goitres were very common. The reason was very simple: the main (and often only) salt available was rocksalt which is extremely poor in iodine.”
Iodine is currently added to processed table salt so one receives about 0.05mg a day if they use it. It is generally a sufficient dosage to to keep goiter away, but it is not enough to keep hypothyroidism away, nor fibrocystic breast disease, or breast cancer for woman, nor the detox of bromide and flouride from master glands that is required for good health and longevity.
According to studies in the Japanese population the daily intake for many Japanese is about 12.5mg a day. This population has significantly lower breast cancer and thyroid issues than Americans do. When Japanese adopt an American diet their rates go up to the the American level.
Regular unprocessed salt will vary in its amount of iodine depending on where it is sourced from. Unprocessed salt will have a variety of minerals that processed salt does not have.
Bottom line: don’t rely on salt for your iodine intake. get it from other foods…sea foods (like seaweed) are very rich in iodine.