Seaweed

From CRSWiki

There is reason to believe that excessive consumption of seaweed, esp. kombu, might contribute to the development of hyperthyroidism. Here's what a researcher in our group, a lifecourse epidemiologist, said about the issue:

The etiology of thyroid disease is known to be related to three things: excess of iodine/radioiodine, exposure to ionizing radiation, and lack of iodine/previous history of goiter. The papers I referenced earlier give various evidence to these facts. You need some iodine in your diet, not lots, which is why I think most people are avoiding kombu as it is very high.

The point I was trying to make is: thyroid problems are rare, and rarer in men than in women. If you eat a lot of Kombu, live in an area/eat a diet where iodine is supplied through other foods, and are exposed to other risk factors, then you should lay off the kombu. If on the other hand you enjoy it in small amounts as an ingredient in other foods and do not otherwise have large amounts of iodine coming in, you are relatively safe. Your risk of getting thyroid cancer as a result of eating lots of kombu is probably less than your risk as a non-smoker of lung cancer from walking around in cities.