An analysis of data from the NutriNet Brasil study found that individuals who consume more ultraprocessed foods in their diet face an increased risk of depressive symptoms. Overall, those with the highest consumption of ultraprocessed foods had a 42% greater risk of developing depressive symptoms compared to those with the lowest consumption. The research was published in the journal Clinical Nutrition.
Ultraprocessed foods are industrially formulated products made primarily from refined ingredients and additives, with minimal to no whole food content. They typically contain artificial flavors, preservatives, sweeteners, and colorings to enhance taste and shelf life. Examples include soft drinks, packaged snacks, instant noodles, and reconstituted meats. These foods are generally high in calories, sugar, fat, and salt, while being low in nutrients and fiber.
Studies have linked regular consumption of ultraprocessed foods to various health risks, including an increased likelihood of obesity, diabetes, and cardiovascular diseases. Some researchers suggest that consuming certain ultraprocessed foods can lead to food addiction, a condition akin to well-known substance addictions.
Study author André O. Werneck and his colleagues aimed to explore the connection between the proportion of ultraprocessed foods in one’s diet and the development of depressive symptoms. Depression, or major depressive disorder, is one of the leading causes of disability worldwide, with nearly 6% of Brazil’s population diagnosed with the disorder.
A national health survey conducted in 2019 revealed that 11% of Brazilian adults experienced moderate to severe depressive symptoms. The global prevalence of depression has risen in recent years, and some researchers attribute this increase, in part, to the growing consumption of ultraprocessed foods during the same period.
The authors analyzed data from the NutriNet Brasil longitudinal study, which included 15,960 adult participants with an average age of 46 years. Of the participants, 78% were women. None of them had a prior diagnosis of depression or clinical levels of depressive symptoms at the start of the study.
Participants assessed their dietary intake using the Nova24h tool, a web-based dietary recall system aligned with the Nova food classification system. This system provided data on the proportion of various food types in each participant’s diet, expressed as a percentage of total energy intake. It included information on ultraprocessed foods, fruits, vegetables, added sugars, total fats, and other dietary components.
Dietary data were collected during the sixth and twelfth months of the study. Participants also completed assessments of depressive symptoms using the PHQ-2 tool in the 14th, 20th, 26th, 32nd, and 38th months. Participants who scored below three points on the PHQ-2 assessment at the 14th month were included in the analysis, which explored the relationship between the proportion of ultraprocessed foods in their diet and the subsequent development of depressive symptoms.
Results indicated that 2,373 participants developed depressive symptoms during the study period. On average, ultraprocessed foods accounted for approximately 22% of participants’ total energy intake, though this varied widely among individuals. Among the 25% of participants with the lowest consumption of ultraprocessed foods, such foods constituted only 7% of their total energy intake. In contrast, for the 25% with the highest consumption, ultraprocessed foods made up 39% of their total energy intake.
Further analysis revealed that participants with the highest consumption of ultraprocessed foods had a 42% greater risk of developing depressive symptoms compared to those with the lowest consumption.
Additionally, the authors conducted a meta-analysis of six published studies examining the same relationship. This analysis found that individuals with high ultraprocessed food consumption had a 32% greater risk of developing depression compared to those with the lowest consumption levels.
While the study highlights a potential link between depression and ultraprocessed food consumption, its design does not allow for causal inferences. It is possible that components of ultraprocessed foods increase susceptibility to depression. However, other factors may also contribute, such as underlying characteristics that predispose individuals both to consuming ultraprocessed foods and to developing depressive symptoms.
The paper, “Adherence to the ultra-processed dietary pattern and risk of depressive outcomes: Findings from the NutriNet Brasil cohort study and an updated systematic review and meta-analysis,” was authored by Andre O. Werneck, Euridice M. Steele, Felipe M. Delpino, Melissa M. Lane, Wolfgang Marx, Felice N. Jacka, Brendon Stubbs, Mathilde Touvier, Bernard Srour, Maria LC. Louzada, Renata B. Levy, and Carlos A. Monteiro.