I have Hypothyroidism. I'm also a vegetarian and eat soy everyday. My blood levels are checked every 8-12 weeks. Eating soy and other foods people say can effect the thyroid hasn't had any effect on my thyroid levels/function.
Unfortunately I think every food could be listed as "do not eat if you are hypothyroidism" if anyone searched the net hard enough. Seems like every food was named to cause cancer at one time or another too!