It is already known that consuming five portions of fruit and vegetables per day lowers a person's risk of death. Now a new study has found that this may be enough, as consuming more than five portions appears to offer no additional benefits.

Previous studies have suggested that eating more fruit and vegetables could lower a person's risk of death even further and a recent study published in the Journal of Epidemiology and Community Health indicated that seven or more daily portions were linked to the lowest risk of death.

US and Chinese researchers decided to look into this further. They assessed the results of 16 studies involving over 833,000 people and more than 56,000 deaths.

As expected, the study found that people who consumed more fruit and vegetables had a lower risk of death from all causes, especially heart disease.

In fact, the average risk of death from all causes was reduced by 5% for each additional daily portion of fruit and vegetables consumed, while the risk of death from heart disease was reduced by 4%.

However, the researchers found that there was a threshold at around five portions per day. Consuming more than five portions did not reduce the risk of death any more.

The researchers said that their 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," they noted.

However, they added that as well as recommending five portions of fruit and vegetables per day, further emphasis needs to be placed on the adverse effects of obesity, smoking, a lack of exercise and too much alcohol.

Details of these findings are published in the British Medical Journal.