She helped to launch a new fitness regime with the game called MindFit at the House of Lords, and described the results of a trial that suggested that the game could help arrest the ageing of the brain.
"You are your brain and it is vital your brain stays in the best possible working order," the Telegraph quoted Greenfield as saying.
"It is not a guarantee against getting Alzheimer's," added Greenfield who admitted that she did not use MindFit herself.
While her support for the game might not be approved by some of her academic fellows, Greenfield insisted that "MindFit is proven to work in scientific trials".
Presented at the Eighth International Conference of Alzheimer's Disease and Parkinson's Disease earlier this year, the MindFit research was a double-blind clinical trial that suggested that computer-based training improved the brain functioning in people aged 50 or above.
The two-year trial conducted by Professor Amos Korczyn and his colleagues at Tel Aviv University demonstrated that a regular workout with MindFit dramatically improved a range of brain abilities, including short-term memory and simple reaction time, which deteriorate with age.
The researchers assigned 121 volunteers to use either MindFit or a variety of popular computer games. They found that MindFit users experienced significantly greater improvement than the subjects who played conventional computer games, such as Tetris.
Participants assigned to use MindFit showed a 15 per cent improvement in their short-term memory and 19 per cent in simple reaction time. Greenfield said that unlike other computer brain training games, MindFit tailored exercises to an individual's changing needs. "It is designed around you," she said.
"As a population we are increasingly conscious of the benefits of physical exercise to our health. Our challenge is now to increase the amount of time spent on evidence-based methods of brain exercise to enhance the benefits that physical exercise may already offer to brain health," she added.
Greenfield is the director of MindWeavers, an Oxford University spin-out company, which got the MindFit game licensed through collaboration with the Israel based maker CogniFit. The game retails at 89.99 pounds.
"MindFit raises the seriousness of the brain training craze and takes it to the next level," said MindWeavers' Chief Executive Officer, Mr Bruce Robinson.