If they suppress thyroid hormones, does that also mean they'll keep TSH within range?
Certain vegetables can suppress thyroid if eaten in excessive quantities; these include cabbage, cauliflower and broccoli.
However, when eaten in normal quantities these vegetables are not a concern and in fact are very nutritious when part of a healthy and varied diet. Please do not avoid eating these vegetables.
Of more concern is soy. Soy products have a much stronger thyroid suppressing effect than the above vegetables and should be avoided or strictly limited if thyroid function could be a concern.