Google Search Does it again my friend.. go to google put Health + Forums there you go I take it one step further Check the Alexa Ranking to see if they are worth it Traffic Wise
Try healthboards.com You can also try ED Forum. Also try weightlossforum.co.uk and hairlossforum.co.uk
For seo purpose these are the Forums that allow you to put your links. I am unable to post my links their sorry for that
I was also looking for health forums and such an interesting and helpful post you have posted. Thanks for this post...