Is there any way to perform DML operations from visualforce email templates?

Visualforce email templates allow you to include visualforce components with allowDML="true" but there doesn't appear to be any way to actually use DML. But getting these when trying to implement :-

You can't use data manipulation language (DML) operations in a “getxxx” method in a controller.

You can't use data manipulation language (DML) operations in a constructor method in a controller.

So is there any way to do this?