Again, elemental stats don't mean anything when it comes to tanking.
If you're a tank you want HP and DEF, so the food you would eat is Knight's Bread.
However it would be counter productive to lower your VIT under 90 so that you could get the "special effect".

In all my tanking, soloing, and testing, I have not see any significant difference in DEX increasing my ability to land hits, evade attacks, or parry. So for now I say it is broken and a waste of points beyond your base.

When it comes to Accuracy and Evasion the greatest factor is your level vs the mob's level.
Beyond that it will be your weapon, armor and your abilities that enhance your ability to deal damage and take it.