h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Dietary based iodine deficiency has been virtually wiped out in the UK thanks to vegetables being grown in a variety of different places. If you only shop locally you risk eating only vegetables that are grown in iodine-free soil. If your local means 100 miles this should not be a problem, but if it means only the local farmers' market then you could be in need of iodine supplements.

Thank you for that Interesting supplementary information

Isn't that the reason that Iodine is an ingredient in table salt? So I really don't think you need to worry about vegetables any more. It really was relevant though years ago when poor folk had to live off a limited, restricted diet which included a lot of brassicas, cabbage especially. I can't remember the mechanism, but these vegetables make it harder for the body to absorb iodine.

The body uses iodine to make thyroxin, the hormone produced by the thyroid gland. If there is too little iodine in the diet the thyroid gland enlarges, to produce a goitre. This *dietary* condition is unheard of now. Thyroid deficiency, another matter entirely, is very common, but is an auto immune disease affecting 1 in 100 of the population, and is easily controlled by replacement thyroxin, from your doctor.