Bruno Bizzozero Peroni: Does the Mediterranean diet improve symptoms of depression? This is what science says

According to the Lancet Commission on Global Mental Health and Sustainable Development, “all countries can be considered developing countries in the context of mental health.” In recent years, mental illnesses have increased worldwide, and are already among the top ten causes of disease burden.

One of the most prevalent disorders in this area is depression. According to 2021 estimates, it affects more than 330 million people and is related to a deterioration in quality of life and an increased risk of suffering from other diseases.

And although advances in research have demonstrated the effectiveness of psychological and pharmacological treatments, not all patients achieve or maintain remission of symptoms with standard therapy alone.

What we eat matters

When it comes to prevention, the sum of biological, psychological, environmental and social factors involved pose a serious challenge. Several risk factors related to lifestyle have been identified, such as smoking, alcohol or physical inactivity. And among them, food has received special attention from the scientific community.

The fact is that epidemiological studies have found a consistent relationship between high adherence to the Mediterranean diet and a lower risk of depression in the adult population. However, scientific evidence remains limited to answer another question: are interventions based on the Mediterranean diet effective in reducing the symptoms of those who already suffer from depression?

Diet-based interventions against depression

Although the first large-scale epidemiological studies that analyzed the influence of diet on the development of chronic pathologies date back to the 1950s, interest in the relationship between the foods we eat and health is ancient. Hippocrates (approximately 460-370 BCE), considered the father of Western medicine, already established that dietary recommendations were, along with physical activity, one of the essential lifestyle factors to restore balance in sick people.

In the last decade, studies supporting the role of diet-based interventions for mental health have increased. Thus, the International Society for Research in Nutritional Psychiatry advocates that so-called nutritional medicine be considered a central element in psychiatric practice.

When it comes to depression, it is known that adopting unhealthy dietary habits (diets rich in ultra-processed foods and abundant in fats, added sugars, sodium and chemical additives) can promote the release of pro-inflammatory cytokines by the immune system. And this would increase the risk of producing, among other mental health deregulations, depressive symptoms.

Instead, adopting healthy dietary habits such as the Mediterranean diet, rich in foods such as fruits, herbs, spices, virgin olive oil, whole grains, nuts and vegetables, provides a source of bioactive compounds with strong antioxidant properties, which can affect positively to the main biological mechanisms (oxidative stress and pro-inflammatory state) of depression.

Evaluation of the Mediterranean diet as therapy

To verify this, we have carried out a study that synthesizes five clinical trials with 1,507 adults between 22 and 53 years old. Our work evaluated the effect of interventions based on nutritional education – through dietary recommendations and food administration that promoted adherence to a Mediterranean diet – with a duration of 2 to 48 weeks.

Thus, we were able to determine that those who joined the intervention group based on the Mediterranean diet reported a lower number of depression symptoms after treatment compared to adults in the control group, both from a statistical point of view and in relation to a clinical perspective. .

These effects could be attributed to the fact that a healthy diet such as the Mediterranean diet would be able to reduce the levels of specific systemic inflammatory markers – such as C-reactive protein – associated with depressive behaviors.

Lifestyle interventions, primarily based on promoting healthy eating, could play an important role in alleviating patients’ symptoms. And without side effects. While more large-scale, long-term clinical trials across all adult ages are needed to draw stronger conclusions, the results are promising.

This article has been published in ‘The Conversation’.