Zimbabwe's President Robert Mugabe has denied reports he has cancer, joking that he has died and been resurrected more times than Jesus Christ.On his 88th birthday, he told state radio: "I am fit as a fiddle".Making light of numerous media reports of his sickness, the Roman Catholic Mr Mugabe said: "I have died many times - that's where I have beaten Christ. Christ died once and resurrected once."After 32 years in power, he is seeking re-election in polls due before 2013.Some reports have suggested that Mr Mugabe's health problems were a reason why he wanted to hold elections this year.His long-time rival, Prime Minister Morgan Tsvangirai, wants a new constitution to be in place before the election.Last year, whistle-blowing website Wikileaks released a US diplomatic cable from 2008, in which central bank governor Gideon Gono was cited as saying Mr Mugabe had prostate cancer and had less than five years to live.Mugabe's health tipsHe told Radio Zimbabwe that his good health was down to his healthy lifestyle - getting up at 0500 to do his exercises and eating well."There are things one must do for oneself. Don't drink at all, don't smoke, you must exercise and eat vegetables and fruit,'' he said, according to AP news agency.Mr Mugabe is accused of widespread human rights abuses during his time in power, including unleashing the army and militias to attack opposition supporters during the 2008 elections.This prompted Mr Tsvangirai to pull out of a run-off, before joining his rival in a power-sharing government which has managed to halt the country's economic meltdown.Mr Mugabe denies the accusations and blames his country's woes on a British-inspired plot to oust him because of his policy of seizing white-owned land.