The -L option to find follows symlinks.
This gives you:
Code:
find -L -type f -name "*" -size +1M -exec md5sum {} \; > file.txt
Just a note which you may or may not be aware of, if you truly want all filenames, you don't need to put -name "*", just leave it out. However, this will also match hidden files like .filename (which what you have will not), so it may not be what you want.
HTH
Forrest