A diet of fruits, vegetables, nuts, plant-based food and fish, typical of a traditional Mediterranean diet, could help lower depression risk, according to new research from UCL.
The study, published today in Molecular Psychiatry, is a comprehensive, systematic overview of the current evidence regarding a link between the quality of people’s diets and the risk of depression. The team of researchers from the UK, Spain and Australia analysed data from 41 studies including 20 longitudinal studies.
“There is compelling evidence to show that there is a relationship between the quality of your diet and your mental health. This relationship goes beyond the effect of diet on your body size or other aspects of health that can in turn affect your mood,” said lead author, Dr Camille Lassale (UCL Epidemiology and Public Health).
“We aggregated results from a large number of studies and there is a clear pattern that following a healthier, plant-rich, anti-inflammatory diet can help in the prevention of depression.”
Of the 41 studies included in this overview, four specifically looked at the link between a traditional Mediterranean diet and depression over time in 36,556 adults. They found that participants from these longitudinal studies with greater adherence to a traditional Mediterranean diet had a 33% lower risk of developing depression than people whose diet least resembled a Mediterranean diet.
The findings also showed that a pro-inflammatory diet with high contents of saturated fat, sugar and processed food was associated with a higher risk of depression in five longitudinal studies of 32,908 adults from France, Australia, Spain, the US and the UK.
The authors said avoiding pro-inflammatory foods and favouring anti-inflammatory foods rich in plant fibre, vitamins, minerals and polyphenols, such as fruits, vegetables, legumes, fish, olive oil and nuts, may reduce the risk of depressive disorders.
“A pro-inflammatory diet can induce systemic inflammation, and this can directly increase the risk for depression. 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.” explained Dr Lassale.
Co-author, Tasnime Akbaraly (Institut National de la Santé et de la Recherche Médicale, Inserm and UCL) added: “By showing that an adherence to healthy dietary patterns is associated with a reduced risk of depressive disorders, we contribute to the growing body of evidence regarding the importance of our daily diets to our mental and brain health. Added to recent randomised trials showing beneficial effects of dietary improvement on depression outcomes, 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.”
The authors note that while the relationship between healthy diet and lower depression risk is now well-established, there is an urgent need for more intervention studies examining the ability of dietary change to improve mental health.