Eating seaweed sounds like it is very beneficial for fast hair growth. On the Long Hair Care Forum there is a discussion about it, one person said:
'Komba, nori, and arame seem to be top ones for hair growth. The Komba had 775% Iodine per serving, the nori 70%, and arame 100%+ of iodine per serving. I remember my hair having a three inch growth spurt in two months time a couple of years ago, and I remember that back then i ate the SAME thing for dinner each night: a bowl of miso soup, salmon, rice, and seaweed added to the miso. I even snacked on seaweed throughout the day.'
Here is the link to that discussion http://www.longhaircareforum.com/forums/showthread.php?t=105659 .
This sounds pretty promising! I have made sushi in the past and I have all the ingredients in my cupboards already, I think i might try to take up eating sushi daily, who's with me?