A new major study is the first to investigate the mental health benefits of a better diet.
For years, scientists have advised that eating more fruits and vegetable can reduce the risk of the two main causes of death — cancer and heart disease.
University of Warwick researchers believe their research suggests that eating more fruit and vegetables can substantially increase people’s later happiness levels. Experts hope this finding will provide additional encouragement for people to improve their diets.
Researchers discovered happiness benefits were detected for each extra daily portion of fruit and vegetables up to eight portions per day. The well-being improvements occurred within 24 months.
From this the investigators concluded that people who changed from almost no fruit and veg to eight portions of fruit and veg a day would experience an increase in life satisfaction equivalent to moving from unemployment to employment.
The study will appear in a forthcoming edition of the American Journal of Public Health.
In the study, researchers followed more than 12,000 randomly selected people. These subjects kept food diaries and had their psychological well-being measured. The authors found large positive psychological benefits within two years of an improved diet.
Professor Andrew Oswald said, “Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human health. People’s motivation to eat healthy food is weakened by the fact that physical health benefits, such as protecting against cancer, accrue decades later.
“However, well-being improvements from increased consumption of fruit and vegetables are closer to immediate.”
The work is a collaboration between the University of Warwick, England and the University of Queensland, Australia. The researchers found that happiness increased incrementally for each extra daily portion of fruit and vegetables up to eight portions per day.
Specifically, the study involved an examination of longitudinal food diaries of 12,385 randomly sampled Australian adults over 2007, 2009, and 2013 in the Household, Income, and Labor Dynamics in Australia Survey.
The authors adjusted the effects on incident changes in happiness and life satisfaction for people’s changing incomes and personal circumstances.
Researchers believe the study has policy implications, particularly in the developed world where the typical citizen eats an unhealthy diet. The findings could be used by health professionals to persuade people to consume more fruits and vegetables.
Dr. Redzo Mujcic, research fellow at the University of Queensland, said, “Perhaps our results will be more effective than traditional messages in convincing people to have a healthy diet. There is a psychological payoff now from fruit and vegetables, not just a lower health risk decades later.”
The authors found that alterations in fruit and vegetable intake were predictive of later alterations in happiness and satisfaction with life. This finding was determined after the authors took into account many other influences, including changes in people’s incomes and life circumstances.
One part of the study examined information from the Australian Go for 25 Campaign. The campaign was run in some Australian states which have promoted the consumption of two portions of fruit and five portions of vegetables each day.
Researchers believe it may be possible eventually to link this study to current research into antioxidants which suggests a connection between optimism and carotenoid in the blood. However, they argue that further research is needed in this area.
Source: University of Warwick