For some years, the prevalence of depressive disorders has been increasing throughout the world and represents a growing public health problem. According to recent estimates, 4% (≈280 million) of the world's population before the pandemic suffered from some type of depressive disorder, a figure that far exceeds those reported in 1990 (3%, ≈180 million). What's more, with the pandemic, at least 53 million additional cases of major depression were added.
These depressive disorders can have a significant impact on general well-being, deteriorating the physical and psychosocial functioning of individuals.
Is there a remedy? Can we reduce those numbers? It is clear that slowing down the accelerated pace of life, combating stress, avoiding social isolation or enhancing contact with nature helps us. However, there is another factor that we do not usually take into account when we think about preventing depression: diet.
In recent years, lifestyle behaviors such as diet have received special attention as feasible daily living strategies to prevent depression. But are we clear about which diet is appropriate and which is not for our state of mind?
The global increase in the adoption of unhealthy (and sedentary) eating habits has generated a large-scale global challenge that alters energy balance and accessibility to natural foods that are important sources of healthy nutrients throughout human history. . I'm talking about fruits, nuts, vegetables and whole grains. This has distanced us from one of the optimal dietary patterns for health with the greatest scientific evidence: the Mediterranean diet, framed in an ancient intercultural culinary tradition.
Instead, we tend to adopt suboptimal diets in which we abuse ultra-processed foods with high levels of sodium, added sugars and trans fats. With an important danger, and that is that excessive intake of this type of food causes our innate immune system to release pro-inflammatory cytokines that, among other things, increase the incidence of certain types of cancer, metabolic syndrome, type 2 diabetes, cardiovascular diseases. , neurodegenerative diseases and depression.
A normal inflammatory response of the human body is characterized by a temporally restricted increase in inflammatory activity when a threat exists, and which resolves once the threat has passed. On the contrary, when we regularly adopt unhealthy eating habits we suffer from low-grade chronic systemic inflammation, which ends up causing significant alterations in all tissues and organs, and, finally, increases the risk of suffering from different non-communicable diseases.
To confirm whether there is a direct relationship between adherence to a pro-inflammatory dietary pattern and the risk of developing depression, we have carried out a longitudinal study with 3,206 Spanish older adults without depression at baseline, evaluating the influence of diet during 3 years of follow-up. We calculated the inflammatory potential of the diet from the Inflammatory Dietary Index, a scoring algorithm based on the impact of different dietary parameters (foods, nutrients and other components of bioactive compounds) on 6 inflammatory biomarkers (C-reactive protein, interleukin-6 , interleukin-1β, interleukin-4, interleukin-10 and tumor necrosis factor-α).
Thus, we were able to determine that those who adhered to a pro-inflammatory diet based on a high consumption of carbohydrates, trans fats, saturated fats, and cholesterol reported a higher incidence of depression throughout the follow-up of the study. Specifically, participants on the highest inflammatory diet were twice as likely to develop depression as participants on an anti-inflammatory diet, based on regular consumption of different nutrients and bioactive components such as dietary fiber, vitamins A, D and E, fatty acids omega 3, beta carotene, zinc, magnesium and selenium. All of them dietary parameters present in foods such as fruits, vegetables, legumes, peas, nuts, fish, shellfish and whole grains, among others.
Although further research is needed throughout adulthood to establish more solid conclusions, these results indicate that eating habits can significantly influence the mental health of older adults. And we would do well to start considering diet as a modifiable element that could positively impact the prevention of depression.
This article was originally published on The Conversation. Bruno Bizzozero is a postdoctoral researcher at the University of Castilla-La Mancha.
