Men who had optimal intake of these three dietary components had a lower risk of prostate cancer, they said.
Commenting on the study, Dr Iain Frame of Prostate Cancer UK said there was not yet enough evidence to make concrete recommendations on which specific foods men should eat to reduce their risk of prostate cancer.
"What we do know is that men shouldn't rely too heavily on one type of food, such as tomatoes," he said.
"A healthy, balanced diet with plenty of fresh fruit and vegetables, together with regular exercise is by far the best option."
Tom Stansfeld of Cancer Research UK added: "While eating foods rich in lycopene - such as tomatoes - or selenium may be associated with a reduction in the risk of prostate cancer, this has not been proven, and this study can't confirm whether there is a link between diet and prostate cancer risk.
"Diet and cancer prevention is a complex issue with few black and white answers; we encourage everyone to eat a balanced diet which is high in fruit and vegetables and low in red and processed meat, fat and salt."
The research, published in the journal Cancer Epidemiology, Biomarkers & Prevention, was carried out in collaboration with the Universities of Cambridge and Oxford.