Mediterranean diets may help prevent depression, research suggests

Adopting a diet that is heavy on plants, nuts and fish could help ward off depression according to a major review on how the food you eat can affect your mental health.

Compared with stereotypical western diets – heavy on meat, processed foods, saturated fat and sugar – people who more closely follow the classic Mediterranean diet were around 33 per cent less likely to develop depression.

Mental health is a growing priority for the NHS and other health systems and the researchers argue that “dietary counselling” by doctors could help improve wellbeing and reduce costs from treatment and lost productivity.

The researchers, led by University College London, reviewed dietary habits of 36,000 people in France, Australia, Spain, the US and UK and found similar patterns around the world.

“There is a robust association between both higher adherence to a Mediterranean diet and lower adherence to a pro-inflammatory diet and a lower risk of depression,” they write in the journal Molecular Psychiatry.

Inflammation is part of the body’s immune response and can increase with emotional states like stress, as well as diet – with fatty, sugary foods and excessive alcohol being key culprits.

Fruit and vegetables, legumes and nuts all tend to be higher in fibre, vitamins, minerals and anti-oxidant dense polyphenols which can reduce inflammation.

“A pro-inflammatory diet can induce systemic [body-wide] inflammation, and this can directly increase the risk for depression,” said Dr Camille Lassale from UCL.

“There is also emerging evidence that shows that the relationship between the gut and brain plays a key role in mental health and that this axis is modulated by gastrointestinal bacteria, which can be modified by our diet.”

However these claims have been questioned by other academics who say that robust evidence does not exist yet as large trials where thousands of people are randomly assigned to different diet types are so difficult to conduct.

Dr Tasnime Akbaraly, from Inserm, France, who co-authored the study, said: “There are now strong arguments in favour of regarding diet as mainstream in psychiatric medicine.

“Our study findings support routine dietary counselling as part of a doctor’s office visit, especially with mental health practitioners.

“This is of importance at a patient’s level, but also at public health level, especially in a context where poor diet is now recognised to be the leading cause of early death across middle and high-income countries, and at the same time mental disorders as the leading cause of disability.”

Professor Naveed Sattar, from the University of Glasgow, was not involved with the study but said eating healthier would likely bring many benefits, but the mental health claims needed further investigation.

“The only way to prove whether the links are genuine is to conduct large randomised trials in people at risk of depression – such trials would take considerable effort but seem worthwhile to conduct. So far only small trials have been conducted.”