Eating five daily portions of fruit and vegetables could lower the risk of early death from any cause, particularly from cardiovascular disease, but beyond five portions appears to have no further effect.

An international team of researchers found that the average risk of death from all causes was reduced by 5 percent for each additional daily serving of fruit and vegetables, while risk of cardiovascular death was reduced by 4 percent for each additional daily serving of fruit and vegetables. They identified a threshold around five servings per day, after which the risk of death did not reduce further.

The new study conflicts with previous research that suggests that seven or more daily portions of fruits and vegetables were linked to lowest risk of death.

For the study, the research team analyzed results of sixteen studies involving more than 833,000 participants and more than 56,000 deaths. Researchers took into account study design and quality to minimize bias.

In contrast, higher consumption of fruit and vegetables was not appreciably associated with risk of death from cancer.

The researchers suggest that, as well as advice to eat adequate amounts of fruit and vegetables, the adverse effects of obesity, physical inactivity, smoking and high alcohol intake on cancer risk should be further emphasized.

"[The study] provides further evidence that a higher consumption of fruits and vegetables is associated with a lower risk of mortality from all causes, particularly from cardiovascular diseases. The results support current recommendations to increase consumption of fruits and vegetables to promote health and longevity," researchers said.

The findings were recently published in BMJ's Journal of Epidemiology and Community Health.