If an apple a day keeps the doctor away, could eating a bunch of fruit and veg a day save us, not just doctors’ bills but a bundle in counselling fees and antidepressant pills?
According to the findings of a large-scale collaborative study by researchers at England’s University of Warwick and Australia’s University of Queensland (UQ), published in the American Journal of Public Health, the answer is an enthusiastic yes.
The researchers analysed data, including long-term food-and-mood diaries, from 12,385 randomly-sampled Australian adults who participated in the Household, Income, and Labour Dynamics in Australia (HILDA) Survey over 2007, 2009, and 2013.
They found that participants who upped their intake of fresh fruit and vegetables from near-nothing to eight daily portions reported measurable increases in corresponding levels of wellbeing – essentially, the more fruit and veg people ate on a daily basis, the happier they claimed they felt.
“This research has found that happiness increases incrementally for every extra daily portion of fruit and vegetables, up to a total of eight portions per day,” says AUSVEG spokesperson Shaun Lindhe.
Substantial improvements in psychological wellbeing could be expected to occur within two years, the researchers found.
“With these improvements in well-being occurring within 24 months, eating fruit and vegetables on a regular basis can boost your happiness just as quickly as they can improve your health,” Lindhe says, “meaning that vegetable consumption has short-term benefits as well as long-term rewards.”
More fruit and veg key to mental health, finds earlier UK-US study
The UQ-Uni of Warwick study corroborates the findings of an earlier cross-sectional study, ‘Is Psychological Well-being Linked to the Consumption of Fruit and Vegetables?’ conducted by the University of Warwick economics professor Andrew Oswald, Warwick Medical School’s Professor Sarah Stewart Brown, and Professor David Blanchflower from the USA’s Dartmouth College.
It found that happiness and mental health rise in “an approximately dose-response way” with the number of daily portions of fruit and vegetables; that wellbeing peaks at about seven portions; and that this pattern “is remarkably robust to adjustment for a large number of other demographic, social and economic variables”.
The Dartmouth and Warwick researchers study analysed cross-sectional data from three large-scale, randomised, longitudinal British health-and-wellbeing surveys, with a total of around 80,000 respondents. The study explored the relationship between subjects’ levels of daily consumption of fruit and veg, and their scores on seven measures of wellbeing:
- life satisfaction;
- the WEMWBS mental well-being index;
- the GHQ mental disorders index;
- self-reported health;
- nervousness; and
- ‘feeling low’.
The research team found positive, incremental linear correlations between greater daily fresh fruit and veg consumption, and higher self-reported happiness and wellbeing levels across several measures of psychological wellbeing – associations that persisted even after potential confounding factors had been accounted for.
Across all three groups surveyed, the positive effects of fruit and veg consumption on happiness and other measures of wellbeing and calm continued to increase up to at least five and, in most cases, up to seven or eight portions daily, and these positive psychological effects occurred in both the short and long term.
While their findings strongly suggested that eating more fresh fruit and veg, more regularly, benefits psychological as well as physical health, the researchers concluded that further analyses of longitudinal health and wellbeing data – preferably with large, randomised samples and more comprehensive information on diet – were needed.
The UQ-Uni of Warwick study, published in late 2016, is such an analysis. Its findings bring us a step closer to proving, definitively and scientifically, that what we eat does affect how we feel – for better and worse.
What are the implications of the recent findings?
Eating more fruit and veg, it seems, will do more than lessening your risk of succumbing to an array of lifestyle-related diseases down the track. It’s a way to make you feel a greater sense of calm, happiness and overall psychological wellbeing right now.
The findings of the UQ-University of Warwick study provide yet more reasons to adhere to – or preferably, exceed – the Australian Government’s fruit and veg consumption guidelines of 5 (veg) +2 (fruit) a day. Better still, aim for Canada’s recommended 5-10 serves a day.
Indeed, the study’s authors suggest that Australia’s guidelines may need to be revised upwards to include an additional two or three servings of fruit as well as five serves of veg per day, especially for women.
The hope is that enhanced wellbeing will induce more of us to load our shopping baskets with the good stuff, fresh from the ground and in all its multi-hued, vitamin- and fibre-rich, phytochemical-packed variety.
“Previous research has found that the long-term physical benefits of eating fresh vegetables aren’t necessarily enough to motivate consumers to increase their consumption, even when these benefits are widely known and understood,” says Lindhe.
“Hopefully, the industry will be able to use these findings to communicate the full range of benefits that vegetables can offer consumers, from physical health to mental health.”
And with Australia’s veritable glut of fine fresh produce, there’s really no excuse not to be eating more of it.
“Australians are extremely lucky to have access to the delicious, high-quality fresh vegetables produced by local Australian growers,” Lindhe notes.
“With all these benefits on offer, we encourage consumers to take advantage of the great produce growing right in their back yard.”
For more information about the study, read the published article in the American Journal of Public Health.
Or check out these earlier, related papers:
'Is Psychological Well-being Linked to the Consumption of Fruit and Vegetables?' David G. Blanchflower (Bruce V. Rauner Professor of Economics, Dartmouth College, USA), Andrew J. Oswald (Professor of Economics, University of Warwick, CAGE UK and IZA Germany) and Sarah Stewart-Brown (Professor of Public Health at Warwick Medical School). October 2012.
To contact Dr Stranges or Professor Stewart-Brown, contact Kelly Parkes-Harrison, Senior Press and Communications Manager, University of Warwick, email@example.com