Five daily portions of fruit and vegetables won't just help stave off disease - they could also keep the blues away.

A new study has found a person's mental wellbeing may be closely linked to how much fresh produce they eat.

Mental wellbeing was was defined as a state in which people feel good and function well, the researchers said.

More than a third of people with high mental wellbeing - meaning they felt happy, had high self-esteem and good relationships - ate five or more portions of fruit and vegetables a day, according to new research

Optimism, happiness, self-esteem, resilience and good relationships with others are all part of this state, they added.

More than a third of people with good mental wellbeing ate five or more portions of fruit and vegetables a day, compared with only 6.8 per cent who ate less than one portion.

A further 31 per cent of those with high mental wellbeing ate three to four portions and 28 per cent ate one to two portions.

Previous research has shown that eating plenty of fresh fruit, vegetables helps prevent people from developing more than one chronic disease.

Chronic diseases include high blood pressure, very high cholesterol, diabetes, arthritis, hepatitis, heart disease, asthma, stroke and cancer.

The study - carried out by Warwick University's medical school - used figures from the Health Survey for England.

It found the effect on mental wellbeing from eating more fruit and vegetables was found in both men and women.

Dr Saverio Stranges, who led the study, said: 'Along with smoking, fruit and vegetable consumption was the health-related behaviour most consistently associated with both low and high mental wellbeing.

MENTAL WELLBEING: WHAT IS IT? The researchers say mental wellbeing is more than the absence of symptoms or illness. Instead, it is a state in which people feel good and function well, the researchers said. Optimism, happiness, self-esteem, resilience and good relationships with others are all part of this state, they added. Advertisement

'These findings suggest that fruit and vegetable intake may play a potential role as a driver - not just of physical - but also of mental wellbeing in the general population.'

Researchers said mental wellbeing is strongly linked to mental illness and mental health problems like depression and anxiety.

It is important not just to protect people from mental illness but because it protects people against both common and more serious physical diseases, they added.

Co-author Professor Sarah Stewart-Brown said: 'Mental illness is hugely costly to both the individual and society, and mental wellbeing underpins many physical diseases, unhealthy lifestyles and social inequalities in health.

'It has become very important that we begin to research the factors that enable people to maintain a sense of wellbeing.'

'Our findings add to the mounting evidence that fruit and vegetable intake could be one such factor and mean that people are likely to be able to enhance their mental wellbeing at the same time as preventing heart disease and cancer.'

The study was published in the BMJ Open medical journal.