Eating your "5 a day" increases changes of higher mental well-being, the researchers say.
A previous study suggested that consuming five portions of fruits and vegetables a day is the optimum amount for lowering the risk of death from any cause, which contradicts another study that suggested we should be eating seven portions of fruit and veg a day.
The researchers from this latest study, led by Dr. Saverio Stranges of the University of Warwick Medical School in the UK, used data from the Health Survey for England, which included nearly 14,000 adults over the age of 16.
This survey collected detailed information on the mental and physical health of the participants, as well as their health-related behaviors, demographics and socio-economic characteristics.
In addition, the team assessed the participants' mental well-being using the Warwick-Edinburgh Mental Wellbeing Scale, putting the top 15% of participants in the "high mental well-being" group, the bottom 15% in the low group, and those between 16-84% in the middle group.
'The higher the veg and fruit intake, the lower the chance of low well-being'
Overall, the researchers found that high and low mental well-being were typically associated with the participants' fruit and vegetable intake.
In detail, 35.5% of participants with high mental well-being ate five or more portions of fruits and vegetables a day, compared with only 6.8% who consumed less than one portion.
Additionally, 31.4% of the individuals from the high mental well-being group ate three to four fruit and veg portions per day, and 28.4% ate one to two.
"The data suggest that [the] higher an individual's fruit and vegetable intake, the lower the chance of their having low mental well-being," says Dr. Stranges.
The researchers also considered other health-related behaviors - such as smoking, alcohol intake and obesity - and found that only smoking and fruit and vegetable intake were consistently associated with mental well-being.
Dr. Stranges explains:
"Along with smoking, fruit and vegetable consumption was the health-related behavior most consistently associated with both low and high mental well-being. These novel findings suggest that fruit and vegetable intake may play a potential role as a driver, not just of physical, but also of mental well-being in the general population."
Alcohol intake and obesity were associated with low, but not high mental well-being, the researchers add.
Enhancing well-being while preventing cancer
According to the team, high mental well-being is more than simply the absence of symptoms or illness - it is the condition of feeling good and functioning well. They add that optimism, happiness, self-esteem, resilience and good relationships are also part of this mode of being.
According to co-author Prof. Sarah Stewart-Brown, mental illness "is hugely costly to both the individual and society, and mental well-being underpins many physical diseases, unhealthy lifestyles and social inequalities in health."
She says enabling people to maintain good well-being is important from a research perspective.
"Our findings add to the mounting evidence that fruit and vegetable intake could be one such factor and mean that people are likely to enhance their mental well-being at the same time as preventing heart disease and cancer," she adds.
When asked about whether the study accounted for physical activity, Dr. Stranges told Medical News Today that one of the limitations of the study was that such data "was not available in the Health Survey for England," leaving room for further study.