Researchers have found that eating five servings of fruit and vegetables a day can have a huge impact on life expectancy.

Researchers from Cambridge University revealed on Tuesday that people can add as much as 14 years to their lives if they adopt four principles for a healthy lifestyle.

Monitoring the health of 20,000 men and women aged between 45 and 79 from Norfolk in the UK between 1993 and 2006, academics have found that not smoking, taking exercise, drinking in moderation and eating five servings of fruit and vegetables a day can have a huge impact on life expectancy.

The study, published in the journal The Public Library of Science Medicine, is one of the first to look at the combined impact of the four factors on life expectancy.

Overwhelming evidence has shown that these things contribute to healthier and longer lives, but the new study actually quantifies their combined impact, the British team said.

The researchers said: “These results may provide further support for the idea that even small differences in lifestyle may make a big difference to health in the population and encourage behaviour change.”

The research showed that a person’s social class or body mass index (BMI) had no role to play in life expectancy.

Between 1993 and 1997 the researchers questioned 20,000 healthy British men and women about their lifestyles. They also tested every participant’s blood to measure vitamin C intake, an indicator of how much fruit and vegetables people ate.

Then they assigned the participants a score of between 0 and 4, giving one point for each of the healthy behaviours. After allowing for age and other factors that could affect the likelihood of dying, the researchers determined people with a score of 0 were four times as likely to have died, particularly from cardiovascular disease.

The researchers, who tracked deaths among the participants until 2006, also said a person with a health score of 0 had the same risk of dying as someone with a health score of 4 who was 14 years older.

The lifestyle change with the biggest benefit was giving up smoking, which led to an 80% improvement in health, the study found. This was followed by eating fruits and vegetables.

The study concluded: “The results strongly suggest that these four achievable lifestyle changes could have a marked improvement on the health of middle-aged and older people, which is particularly important given the ageing population in the UK and other European countries.”