Iodine is vital for good thyroid function, which in turn is essential for health. Iodine deficiency during pregnancy and early infancy can result in cretinism (irreversible mental retardation and severe motor impairments). In adults low iodine intake (or very high intakes) can cause hypothyroidism. Hypothyroidism can manifest as low energy levels, dry or scaly or yellowish skin, tingling and numbness in extremities, weight gain, forgetfulness, personality changes, depression, anaemia, and prolonged and heavy periods in women. Goiter, an enlarged thyroid gland visible between the Adam's apple and the collar bone, is often present. Hypothyroidism can also cause carpal tunnel syndrome and Raynaud's phenomenon. Hypothyroidism can lead to significant increases in cholesterol levels and homocysteine levels is implicated in about 10% of cases of high cholesterol levels. Correcting hypothyroidism can lead to a 30% drop in cholesterol and homocysteine levels.
An iodine intake of less than 20 micro grams (µg) per day is considered severe deficiency, 20 -50 µg/day is considered moderate deficiency and 50-100 µg/day is considered mild deficiency.
..etc, more on that at the website. the bit that interested me was this:
If using seaweeds as an iodine source it is best to use seaweeds that have been found to have a fairly consistent iodine content, such as kelp (kombu) or hijiki. Consumption of more than 100g/year (by dried weight) of most seaweeds carries a significant risk of thyroid disorder due to iodine intakes in excess of 1000 micrograms per day.
Nori is low in iodine and several sheets a day can be eaten without any concern about excess iodine. Frequent addition of small amounts of powdered or crumbled seaweed to stews or curries while cooking, or to other foods as a condiment, is an excellent way to provide adequate iodine (in the absence of other supplementation) and is a healthful practice for vegans. 100g of dried hijiki or 15g of dried kombu or kelp in a convenient container in the kitchen provides one year's supply for one person.
-- I'm just wondering if Japanese people are (in general) more likely to be overly skinny than not because of their iodine intake. Apart from all the other factors like genetic inheritance, cultural aspects etc.
here is the link to the actual site -- http://www.vegansociety.com/html/food/nutrition/iodine.php
ps. dear mods -- someone took out the only copy of 'killing aurora' in the library. it's not due back there for another week and a half; but i'll get it out then to fix up that entry where i half rec'd it. sorry for the delay.