Researchers found that people who switched from eating almost no fruit and vegetables in their daily diets to eating eight portions of fruit and vegetables a day experienced an increase in life satisfaction equivalent to what an unemployed person feels after finding a job.
The improvements in the people’s life satisfaction occurred within two years of the changes to their diets.
“Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human health,” study co-author Redzo Mujcic, a health economics research fellow at the University of Queensland in Australia, said in a statement.
Previous research has shown that eating more fruits and vegetables leads to improvements in people’s physical health, but these benefits typically occur over longer periods of time, the researchers said.
“People’s motivation to eat healthy food is weakened by the fact that physical-health benefits, such as protecting against cancer, accrue decades later,” Mujcic said. In contrast, improvements in psychological well-being may happen faster, he added.
In the study, researchers looked at more than 12,000 people in Australia, following them for two years. The researchers asked the people whether they normally ate fruit and vegetables, and how much they ate. Investigators also asked the study participants how satisfied they were with their lives, on a scale from 0 to 10. The researchers then tracked the people’s diets, including whether they had increased their consumption of fruits and vegetables during the study period, and their life satisfaction levels for two years.
Results showed that in the people who began eating more fruit and vegetables per day during the study period, the levels of life satisfaction increased by the end of the study.
The relationship between higher levels of life satisfaction and increased fruit and vegetable intake persisted even after the researchers accounted for changes in the people’s income or other life circumstances, according to the study, which will be published in the August issue of the American Journal of Public Health. And previous research has suggested that it isn’t likely that the link works the other way — that people who start feeling happier start eating more fruits and vegetables, the researchers said.
It is not clear why eating more fruit and vegetables would be linked to greater levels of life satisfaction, the researchers said. However, previous research has suggested that greater levels of pigments called carotenoids, found in some fruits and veggies such as carrots, are linked to higher levels of optimism. Studies have also suggested that an increased intake of vitamin B12, also present in fruits and vegetables, may boost a neurotransmitter in the brain called serotonin, which plays a role in regulating mood, the researchers said.
The new findings may help doctors convince people to eat more fruits and vegetables, Mujcic said. “Perhaps our results will be more effective than traditional messages in convincing people to have a healthy diet,” he said. “There is a psychological payoff now from fruit and vegetables, not just a lower health risk decades later.”
“The results showed that there was a direct impact in terms of the amount of fruits and vegetables someone had and their overall well-being,” said Antonella Apicella, nutritionist at Lenox Hill Hospital, in New York City, who was not involved in the study. The relationship between nutrition and emotional health is a new, hot research topic that should be studied further in the future, she said.