User blog comment:AYET/Shanks missing arm/@comment-4605926-20120221123837

In other words what you're asking is, "if Shanks ate ANY Logia Devil Fruit (not necessarily the Mera Mera no mi), would he be able to regrow his missing arm" am I correct?

Well, the Logia powers only nullify the damage received by certain attacks, they don't regenerate what is already lost. Examples for this are Ace's death and Crocodile's hook hand. If Logia users would've really been able to regenerate physical injuries then they would practically be invincible.