[Caz]

Brussel sprouts,  turnips, cauliflower, cabbage  almonds, peanuts and walnuts sweet corn,  
soya – this combined with a high fibre diet causes too much thyroid hormone and iodine to be excreted from the body.
raw Swedes, turnips and kale - These are sometimes fed to cattle and comes to us via their milk products.

Did you know that fluoride was used in the past to treat hyperthyroidism and that it was frequently used at levels below the current “optimal” intake of 1mg per day. Did you know that Fluoride is able to mimic the action of TSH? Researcher Andreas Schuld has found that excess fluoride correlates with other thyroid-related issues such as iodine deficiency. When there is excess of fluoride in the body it can interfere with the function of the thyroid gland.

Oestrogen
Any oestrogen raises the levels although thyroid activity is unchanged. This could make your levels look within the normal range, whereas they are really below it. Oestrogen provides more of the transport protein, making the hormone inactive. After starting on any oestrogen therapy, a woman should always have TSH tested to see if the oestrogen is having an impact on overall TSH and thyroid function and might require a dosage adjustment.

Ask your doctor about taking any vitamin supplements.
hypothyroidism tends to affect the absorption of necessary vitamis and minerals, so you need to keep a check on your balance. But many supplements have iodine. Always check with your GP or Chemist.