These products, unfortunately, are widely available. In the US, they represent 70% of packaged foods, according to the authors of the study conducted by Florida Atlantic University and published in the journal “Public Health Nutrition”.
To carry out their research, they worked with a large panel of 10,359 American adults who had never before used drugs. For one month, the researchers measured “mild depression”, as well as the number of “mental unhealthy days” and “anxious days”.
A questionnaire was filled out daily by the volunteers.
To measure the quality of food, the researchers used the classification system called Nova, adopted by the United Nations’ Food and Agriculture Organisation, which differentiates food products into four categories:
- unprocessed or minimally processed foods;
- processed culinary ingredients;
- processed foods; and
- ultra-processed foods.
They found that those who ate the most ultra-processed foods showed symptoms of poor mental health compared with those who ate less. Ultra-processed foods are products that contain oils, fats, sugar, starch, as well as flavours and dyes, with little to no whole foods in their composition.
Among the most common products are sodas, sweet snacks, and ready-made meals. Once consumed, these are deleterious to the brain and, therefore, mood.
“Poor diets dysregulate brain insulin, which decreases neuronal levels of serotonin and dopamine, and increases neuroinflammation as measured by inflammatory cytokines,” the researchers wrote.
Serotonin is known as the hormone of happiness, while dopamine is the hormone of immediate pleasure.
“Data from this study add important and relevant information to a growing body of evidence concerning the adverse effects of ultra-processed consumption on mental-health symptoms,” they added.