We've all heard the time-honoured aphorism "an apple a day keeps the doctor away", but new research suggests that our minds could be uniquely altered by our diet.

In a précis of their recent study, Professor Peter Howley and Dr Neel Ocean, economists at the University of Leeds, said that improving one’s mental health could be as "as simple as eating an extra piece of fruit every day or having a salad with a meal".

Although the researchers denied that fruits and vegetables can serve as viable alternatives to medical treatments, they pointed to the chemical benefits of vitamins C and E – both of which have been shown to reduce some types of depression-associated inflammation.

Their paper, which surveyed 40,000 participants from the UK Household Longitudinal Study was funded by the Global Food Security Resilience of the UK Food System Programme and published in the peer-reviewed journal Social Science and Medicine.

While the project team's results seem promising, it's important to remember that they are not definitive indicators of a causal link between the consumption of fruits and vegetables and mental wellness.

For example, in an analysis of the study, Bazian consultants – writing on behalf of the NHS – acknowledged that its data might have been influenced by other "confounding" factors.

"The possibility that people who feel happier are more likely to choose healthier food, for example, cannot be ruled out, " the consultants explained.