While the authors did not find a direct association between brain changes and anxiety or depression, they did see an increase in rumination, a common risk factor of the two.
The study is the first to examine the relationship between diet quality and brain neurochemistry in humans. Thirty adults were divided into two groups based on whether they followed a high- or low-quality diet. Participants in both groups were similar in age, gender, education, income, and caloric and macronutrient intake.
The quality of the diet was defined by adherence to the Mediterranean diet. Participants reported how frequently they ate 130 different food items, their consumption frequency, and food intake habits. Screening questionnaires were administered to assess current depression, anxiety, and rumination levels. Whole brain MRI scans measured prefrontal cortex metabolite concentrations and gray matter volume.