Eating raw fruit and vegetables such as kiwis, bananas, apples, dark leafy greens, cucumber, and carrots may lower symptoms of depression and improve mental health, more than cooked, canned and processed food, say researchers.
The findings showed that consuming raw fruits and vegetables leads to lower levels of mental illness symptomatology, such as depression.
It also improved levels of psychological well-being including a positive mood and life satisfaction.
"Our research has highlighted that the consumption of fruit and vegetables in their 'unmodified' state is more strongly associated with better mental health compared to cooked/canned/processed fruit and vegetables," said lead author Tamlin Conner, senior lecturer at the University of Otago in Dunedin, New Zealand.
However, when the fruits and vegetables are cooked, canned and processed, they lose their mental health benefits as the process potentially diminishes the nutrient levels, Conner noted.
"Cooking and processing likely limits the delivery of nutrients that are essential for optimal emotional functioning," Conner said.
For the study, published in the journal Frontiers in Psychology, more than 400 young adults from New Zealand and the US aged 18 to 25 years were surveyed. Conner says public health campaigns have historically focused on aspects of quantity for the consumption of fruit and vegetables (such as 5+ a day). However, the new study found that for mental health in particular, it may also be important to consider the way in which produce was prepared and consumed.
"This research is increasingly vital as lifestyle approaches such as dietary change may provide an accessible, safe and adjuvant approach to improving mental health," Conner said.