Eating three to four serves of vegetables daily is associated with a lower incidence of psychological stress, new research by University of Sydney scholars reveals.
Published today in the British Medical Journal Open, the longitudinal study of more than 60,000 Australians aged over 45 participating in the Sax Institute’s 45 and Up Study measured fruit and vegetable consumption, lifestyle factors and psychological distress at two time points, 2006-08 and 2010.
Psychological distress was measured using the Kessler Psychological Distress Scale, a 10-item questionnaire measuring general anxiety and depression. Usual fruit and vegetable consumption was assessed using short validated questions.
“This study shows that moderate daily fruit and vegetable consumption is associated with lower rates of psychological stress,” said Dr Melody Ding of the University of Sydney’s School of Public Health.
“It also reveals that moderate daily vegetable intake alone is linked to a lower incidence of psychological stress. Moderate fruit intake alone appears to confer no significant benefit on people’s psychological stress.”
These new findings are consistent with numerous cross sectional and longitudinal studies showing that fruit and vegetables, together and separately, are linked with a lower risk of depression and higher levels of well-being assessed by several measures of mental health.
“We found that fruit and vegetables were more protective for women than men, suggesting that women may benefit more from fruit and vegetables,” said first author and University of Sydney PhD student, Binh Nguyen.
The investigators say further studies should investigate the possibility of a ‘threshold’ between medium and higher levels of fruit and vegetable intake and psychological stress.
This research was based on data from the Sax Institute’s 45 and Up Study, Australia’s largest ongoing health study involving a quarter of a million people – one in every 10 men and women aged 45 and over in NSW.