Ryan, R-Wis., spoke on NBC's "Meet the Press," where a week earlier Gingrich, a former House speaker, dismissed his proposal as "right-wing social engineering."
Facing universal outrage from Republicans, Gingrich apologized and tried to retract his statement.
"His quote was deeply inaccurate. It was a gross mischaracterization of the House Republican budget plan," Ryan said Sunday.
"This is as sensible and gradual as it gets. … If I could put it in a nutshell, we're saying don't affect current seniors, give future seniors the ability to deny business to inefficient providers.
"As a contrary to that, the president's plan is to give the government the power to deny care to seniors by empowering a panel of 15 unelected bureaucrats to put price controls and rationing in place for current seniors," Ryan said.
Ryan also expressed regret that Indiana Gov. Mitch Daniels is not running for president and repeated that he will not do so himself.
'Happy' fan videos make Pharrell cry [VIDEO]
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend