Vitamin is about SEO, speed and security. It includes sitemaps for SEO, cache for speed, antispam and hacker blocks for security.
Vitamin messed up my theme. It took me days to figure out that vitamin was the culprit.
I tried to uninstall, and vitamin has apparently hooked into the wordpress install, so if it is uninstalled, it makes my site show as a blank page. I have to restore from a back up to make it show again.
I can't say for sure, but at the same time as these problems cropped up, my rss feed stopped broadcasting, and since I can get it to broadcast briefly during restores, I really think its the vitamin.
I think I will have to delete and reinstall my wordpress in order to get my rss working again.
This plugin is dangerous. STAY AWAY