A healthy pattern diet, consisting of an adequate balance of fruits, vegetables, nuts, legumes and fewer processed meats has been found to prevent the onset of depression. A wide-scale study based on 15,093 participants suggests that depression could be significantly associated with nutrient deficiencies.

Exploring The Link Between Diet And Mental Health

After elaborate research into the effects of diet on physical health, scientists are now investigating the association between nutrition and mental well-being.

This is the first study that manages to analyze the link between various healthy diet patterns and the risk of depression.

The 15,093 participants were free from depression at the start of the study. They were all former students of the University of Navarra, Spain, and enrolled in the cohort study that began on 21st December 1999. This study has been used to identify lifestyle and dietary determinants of many diseases, such as obesity, diabetes and depression.

Three dietary patterns were compared – Mediterranean Diet, Pro-vegetarian Dietary Pattern and Alternative Healthy Eating Index (2010). A scoring system was given to the participants to evaluate their inclination towards a selected diet – the higher their dietary score, the healthier their diet. For example, meat, sweets and saturated or trans-fatty acids were negatively scores, whereas fruits, nuts, vegetables, omega-3s, vitamins and minerals were positively scored.

Participants completed questionnaires assessing their dietary intakes at the beginning of the study, and then again after 10 years.

“We wanted to comprehend the role played by nutrition in mental health, since we believe that certain dietary patterns could protect our minds”, explained lead researcher Almudena Sanchez-Villegas from the University of Las Palmas de Gran Canaria. “All the diets administered in the study are associated with physical health benefits, and we now observe that these nutrients could have a positive impact on our mental health as well, such as reducing the risk of depression”.

Which Nutrients Could Be Beneficial?

Clinical depression was reported by 1,550 participants, while some had used antidepressants after a median follow-up of 8.5 years.

The greatest reduction in the risk of depression was associated with the Alternative Healthy Eating Index (2010), but most of the effects were accounted for by similarities with the Mediterranean Diet. Hence, foods and nutrients common to both omega-3s, fruits, vegetables, nuts, legumes and moderate consumption of alcohol could be involved in reducing the risk of depression.

Almudena Sanchez-Villegas stated that a ‘threshold effect’ might be at work. Obvious differences start to occur when participants adhere to a healthier diet, even moderately. Thus, even a small shift towards a more balanced and nutritious diet could significantly reduce the risk of developing depression.

“Once the threshold is achieved, the reduction in risk plateaus, even if the participant was stricter with his or her diet and ate more healthily. This ‘dose-response pattern’ corroborates the hypothesis that suboptimal intake of certain nutrients (mainly located in low adherence levels) represents a risk factor for depression in the long-run”.

Study Limitation

Despite the potentially considerable findings, there was a limitation in the study. The results were based on self-reported dietary intakes and a self-reported clinical diagnosis of depression.

Further research is required to conclusively predict the role played by nutrients in maintaining neurophysiological health, and also whether macronutrients or micronutrients are significantly associated with depression. The research was published in the open access journal BMC Medicine.