Eating at least seven portions of fruit and vegetables every day is healthier than the publicized "five a day" and would make people live longer, according to a new research published on Tuesday.

Currently, Britain's National Health Service recommend that every person in Britain should try to have five different 80g portions of fruit and vegetables a day, based on advice from the World Health Organization.

However, in a new study published in the Journal of Epidemiology and Community Health, researchers found that an increase in daily fruit and veg intake linked to lower chances of death from stroke and cancer, and could prolong lives.

The researchers from University College London examined the eating habits of 65,000 people in England between 2001 and 2008, and found that people who ate seven or more portions daily had a 42 per cent reduced risk of death overall compared to those who had just one.

They also found that, fresh vegetables had the strongest protective effect, followed by salad and then fruit. Overall, vegetables pack more of a protective punch than fruit. But people who ate canned or frozen fruit had a higher risk of heart disease, stroke and cancer.

The authors of the paper said it could be that people eating canned fruit may not live in areas where there is fresh fruit in the shops, which could indicate a poorer diet.

"The clear message here is that the more fruit and vegetables you eat, the less likely you are to die -- at any age," lead author Dr Oyinlola Oyebode said, adding that the size of the effect was "staggering."

However, eating a few portions a day was still better than nothing, she added.