Australian researchers found that people who switched from almost no fruit and veg to eight portions of fruit and veg a day recorded an increase in life satisfaction. The boost in mental well-being occurred within 24 months.
Additionally, happiness levels were noted for each extra portion of fruit and vegetables up to eight portions per day.
The study has policy implications, particularly in the developed world, where fruit and vegetables in the diet are sorely lacking as the findings could be used to persuade people to consume more of these foods.
Dr Redzo Mujcic, research fellow at the University of Queensland and study co-author spoke of the ‘psychological payoff from fruit and vegetables -- not just a lower health risk decades later.’
“Perhaps our results will be more effective than traditional messages in convincing people to have a healthy diet,” he added.
The findings appear to go further than the World Health Organisation (WHO)/Food and Agriculture Organisation (FAO) report, which recommends 400 g edible fruit and vegetables per day in order to prevent non-communicable diseases. These guidelines for the European region, were put in place to also help prevent and alleviate several micronutrient deficiencies. 400 g translates to roughly five portions per day. Other countries such as France recommend 10 portions of fruit and vegetables a day.
The study follows-up on an earlier research that defined the optimal consumption at four to five daily portions of fruit and four to five daily portions of vegetables.
Here, food diaries of 12,385 randomly sampled Australian adults were examined over 2007, 2009, and 2013 in the Household, Income, and Labour Dynamics in Australia Survey.
Events such as changing incomes and personal circumstances were adjusted for their effect on happiness and life satisfaction.
Results demonstrated that increased fruit and vegetable consumption was predictive of increased happiness, life satisfaction, and well-being.
A points-based system of 0 - 10 was used to indicate how satisfied the subject was. The more satisfied they were the higher the number.
Researchers found that for an increase of eight portions a day, life-satisfaction points went up by up to 0.24. Researchers equated this jump to the psychological gain of moving from unemployment to employment.
“Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human health,” said Andrew Oswald, professor of Economics and Behavioural Science at the University of Warwick, UK.
“Well-being improvements from increased consumption of fruit and vegetables are closer to immediate.”
The team acknowledged the challenges arising from their research, such as carrying out a randomised trial.
“A double-blind procedure would not be feasible, so placebo effects would be hard to disentangle,” they commented.
Large-scale longitudinal studies, of the kind mentioned in the research, would still be needed to form a convincing argument as to the findings’ validity.
Source: American Journal of Public Health
Published online ahead of print, DOI: AJPH.2016.303260
“Evolution of well-being and happiness after increases in the consumption of fruit and vegetables.”
Authors: Redzo Mujcic and Andrew Oswald