The effect of ingesting seaweed "Kombu" (Laminaria japonica) on thyroid function was studied in normal Japanese adults.
Ingesting 15 and 30g of Kombu (iodine contents: 35 and 70 mg) daily for a short term (7-10 days) significantly increased serum thyrotropin (TSH) concentrations, exceeding the normal limits in some subjects. The serum free thyroxine (FT4) and/or free 3,5,3'-triiodothyronine (FT3) concentrations were slightly decreased within the normal limits.
During long term daily ingestion of 15g of Kombu (55-87 days), the TSH levels were elevated and sustained while the FT4 and FT3 levels were almost unchanged. Urinary excretion of iodine significantly increased during ingestion of Kombu.
These abnormal values returned to the initial levels 7 to 40 days after discontinuing the ingestion of Kombu.
Based on these findings that thyroid function was suppressed during ingestion of Kombu, though the effect was reversible, we recommend Japanese people avoid ingesting excessive amounts of seaweed.
Gosh, why exactly were the TSH levels increased? I just bought some Detoxified Iodine made from seaweed. Although, it is recommended to go off of it for two days a week. I'm going to try it. My TSH levels are a tiny bit high, I don't want to take a drug for the rest of my life, not even a natural one. I have used Lugol's and Iosol which didn't seem to make much difference. I guess it will be my own "study."
I wonder if this is really inhibiting the thyroid or working in another way, possibly sensitizing the body to the need for iodine through receptor stimulation or something. just a guess
It is the thyroid's job to find iodine wherever it can get it. The body does not produce iodine; so it's not like a laxative dependence. The thyroid will not stop working or slow down in its effort to find iodine in the food. All you are doing is supplementing iodine independent of food.
Most of us are deficient in iodine anyway. One way we are deficient is because the bread makers are using bromate in the breads instead of iodine that was used in the past. Bromine is a halogen like iodine. Bromine tricks the thyroid into "believing" that it is iodine. Bromine displaces iodine. The only way to recover is to supplement with a lot of iodine. The normal daily Japanese diet is 12MG. This means the infirm, children, and even pregnant women. This should not be a problem to supplement with iodine. By the way, Nature's Own has "No Bromates" on the labels of their breads.
I have to disagree with these findings, the researchers are missing a very important point.
TSH has another job aside from telling the body when to make more thyroid or not...TSH also builds the 'roadways' for iodine to travel through the body.
No matter the form, if you hit someone with a high dose of iodine their TSH is expected to spike