An Unhealthy Diet Increases The Risk Of Developing Depression

Depressive disorders are on the rise worldwide, and this is influenced by factors such as lifestyle, stress, and social isolation. However, diet plays an important role in preventing them.

For some years now, the prevalence of depressive disorders has been increasing worldwide and represents a growing public health problem.

According to recent estimates, 4% of the world’s population before the pandemic suffered from some form of depressive disorder, a figure that far exceeds that reported in 1990 (3%). Furthermore, 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, impairing individuals’ physical and psychosocial functioning.

Is there a cure? Can we reduce these figures? It is clear that slowing down the accelerated pace of life, combating stress, avoiding social isolation, or promoting 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.

What is an inflammatory diet and how does it relate to depression?

In recent years, lifestyle behaviors such as diet have received special attention as feasible everyday strategies to prevent depression. But are we clear about which diet is suitable and which is not for our mood?

The worldwide increase in the adoption of unhealthy (and sedentary) eating habits has generated a large-scale global challenge that alters the 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 taken us away from one of the optimal dietary patterns for health with the greatest scientific evidence: the Mediterranean diet, framed in a thousand-year-old 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. A significant danger 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.

An unhealthy diet increases the risk of developing depression — We often abuse ultra-processed foods with excess sodium and these cause the risk of suffering from diseases. (Photo Prensa Libre: Pexels)

A normal inflammatory response of the human body is characterized by a temporarily restricted increase in inflammatory activity when there is a threat, which resolves once the threat has passed. In contrast, when we regularly adopt unhealthy eating habits we suffer from chronic low-grade systemic inflammation, which ends up causing significant alterations in all tissues and organs, and ultimately increases the risk of suffering from different non-communicable diseases.

The probability of developing depression doubles

To confirm whether there is a direct relationship between adherence to a proinflammatory dietary pattern and the risk of developing depression, we conducted a longitudinal study with 3,206 Spanish older adults without depression at baseline, evaluating the influence of diet during 3 years of follow-up.

The inflammatory potential of the diet was calculated 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).

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 study follow-up.

Specifically, participants with the highest inflammatory diet were twice as likely to develop depression than participants with an anti-inflammatory diet, based on regular consumption of different nutrients and bioactive components such as dietary fiber, vitamins A, D, and E, omega 3 fatty acids, beta-carotene, zinc, magnesium, and selenium.

All of these dietary parameters are present in foods such as fruits, vegetables, legumes, peas, nuts, fish, seafood and whole grains, among others.

While further research is needed throughout adulthood to draw more robust conclusions, these results indicate that dietary habits can significantly influence the mental health of older adults. And that we would do well to start considering diet as a modifiable element that could positively impact the prevention of depression.