A brace from Mario Balotelli was enough for Italy despite Mesut Ozil pulling a goal back for Germany from the penalty spot late on in Warsaw.
Loew also took some blame for the spectacular collapse of Germany in the 4-4 draw against Sweden in a UEFA World Cup qualifier, in which his men threw away a four-goal lead.
"With the knowledge I have today, I would probably approach the Italy game differently," Loew told Suddeutsche Zeitung.
"I had a clear plan for that game and of course I have to now admit that the plan did not work.
"Against Sweden, I got (Mario) Goetze and (Lukas) Podolski to drop deeper to try give us more security and that did not work.
"The year 2012 was constructive for all of us and I have certainly learned from it."
Loew's contract with Germany expires in 2014, and the 52-year-old recently said he would be happy to extend his deal, amid rumours he could replace Jose Mourinho at Real Madrid.