torjusg said:
If you live in a mainly inland region, with little or no available iodine through sea fish, how do you make sure you don't get goiter?
I know that icelandic lichen contains iodine, but I don't know if the quantity is sufficient to ensure that you get enough of it. And it isn't exactly tasty.
Any ideas of how to prevent this problem?
Torjus Gaaren
I can't find any figures for iodine constituent in
Iceland Lichen (Cetraria islandica) but it does indeed contain iodine above trace quantities. There are various ways to make the lichen edible including making a jelly form it. And I remember from Ray Mears' 'Heroes of Telemark' how they survived on the semi-digested lichen taken from the stomachs of reindeer as their vegetable ration. Not so tasty though
sandsnakes is spot on recommending kelps or other seaweeds which are rich in iodine, though they would have to be harvested near the sea.
It is one of the main reasons for iodised table salt as Toddy mentioned.
I am guessing that one of the reasons stockfish was so popular was because it also contained iodine in the preserving salt and in the seawater fish itself.
One idea might be obtaining it from fish, normally living in the sea, that migrate into the rivers in the area to spawn. Salmon spring to mind. I know sea trout contain iodine. Trout may also be a source;
Which foods have iodine?
Fatty fish such as haddock, mackerel, herring, salmon and trout, seafood such as muscles and kelp, salt and dairy.
source:
http://www.health24.com/dietnfood/Whats_in_food/15-47-108-113.asp
This would appear to include freshwater species such as rainbow, brown and brook trout, specifically in their thyroid glands. Some info:
Iodine is essential for the biosynthesis of the thyroid hormones, thyroxine and triiodothyronine. Fish obtain iodine from water via branchial pumps and from feed sources (Leloup, 1970). The total uptake of iodine depends on the iodine content of the feed and water (Gregory and Eales, 1975). Under laboratory conditions, rainbow trout derive 80 percent of their iodide from water, 19 percent from diet, and less than 1 percent by recycling iodide from thyroid hormone degradation (Hunt and Eales, 1979).
Iodine deficiency caused thyroid hyperplasia in brook trout (Marine, 1914). Thyroid hormone deficiency has been induced by glucosinolates in the diet (Higgs and Eales, 1978). A deficiency of ascorbic acid caused hypoactivity of the thyroid gland as demonstrated by a reduction in accumulation of 131I by thyroid glands in scorbutic snakehead (Agrawal and Mahajan, 1981). The minimum iodine requirement of most fish species has not been established. Woodall and LaRoche (1964) reported higher iodine requirements for advanced chinook salmon parr compared with fingerlings due to increased thyroid activity during smoltification. Lall et al. (1985) observed that relatively high concentrations of iodine and fluorine (4.5 mg/kg of diet of each) were essential to protect Atlantic salmon from bacterial kidney disease infections.
source:
http://darwin.nap.edu/books/0309048915/html/21.html
Digging a bit more I found some useful figures (extracted from table. other seafoods included to give an broader idea);
Mineral Contents of Selected Fish and Shellfish (mg/100g raw edible portion unless otherwise specified)
Haddock 250 mcg
Cod 110 mcg
Mackerel 140 mcg
Mussel 140 mcg
Salmon(Atlantic) 76 mcg
Herring 29 mcg
Prawn 21 mcg
Trout(Rainbow) 13 mcg
note: mcg = micrograms
source: : Holland, B., Brown, J., & Buss, D.H., 1993. Fish and Fish Products; the third supplement to McCance & Widdowsons The Composition of Foods (5th Edition), HMSO, London.
As to quantities needed;
"Seafood is the richest source of iodine in the normal diet, and one or two seafood meals per week will supply 100-200mcg per day, enough to meet the adult RNI of 140 mcg. Few other commonly eaten foods can match this."
the recommended daily amount (UK RDA) of iodine is 150 micrograms for adults and children over the age of 5.
Then you need to eat
200g of (raw) Salmon a day, or
1.2kg of trout a day to achieve the recommended levels. But given that iodine is available from other sources this is simply assuming a diet really lacking in iodine as you mentioned.
Maybe it is also found in crayfish or freshwater mussels?