This study was conducted to evaluate the association of consumption of whole foods (focused on vegetables, fruit and fish and not heavily processed) with depression. Included in this long-term study were 3,486 people between 35 and 55 years of age, working in civil service departments who were periodically assessed for dietary patterns, social factors and depression. Their food habits were either classified as whole food or processed food. On assessing depression, it was found that those consuming more whole foods scored less on the depression rating than those who had less whole food.
The incidence of certain neurological disorders such as Parkinson’s disease and Alzheimer’s disease is lower in people consuming Mediterranean diets, with its higher proportion of greens and less meat and dairy products. Similarly, previous studies have focused on the influence of diet on depression, focusing on individual nutrients such as fatty acids and vitamins. Of late, studies are looking at dietary patterns rather than individual nutrients. Previous studies have not investigated the relationship between dietary patterns and depression. Thus, this study aims at examining the association between whole food diets, assessed by a food-intake questionnaire, and depression in a population of middle-aged adults.
* The study population consisted of 3,486 healthy middle-aged people. Each participant completed an initial questionnaire and underwent a clinical examination.
* Further questionnaires were carried out through correspondence and consisted of seven phases. Depression was assessed in the last phase, five years later, using a standard test.
* The dietary pattern of the patients was assessed during the fifth phase using a food-item questionnaire. The dietary and depression scale score of each person were noted and statistically analyzed.
* The prevalence of depression was 11.9 percent in the study population.
* Those consuming high levels of whole food reported depression less frequently. There were 416 cases of depression at the end of the study.
* Thirty-one percent of those who had reported having depression were either single or divorced. Also, 18 percent of them had reported less physical activity. Smoking was also more common in those with depression.
In this study, the reverse causation could hold true, which suggests that depression could have caused changes in the dietary patterns. The questionnaire was a semi-quantitative questionnaire on food, and assessing only specific foods, which can be less precise. The participants were mostly office-based workers and they were all Caucasian. Thus, generalization of the results to the larger population is not possible.
The uniqueness of this study is the consideration of whole diets rather than considering specific nutrients. There is evidence of an inter-relation between dietary patterns and depression. Diets rich in fruit, vegetables or fish could be beneficial. The possible mechanisms could be the rich antioxidant content in fruit, the higher levels of folate or the high content of omega-3 poly-unsaturated fatty acids in fish. Processed foods contain more sugars and these have been linked with a higher incidence of depression. Thus the authors conclude, “these findings suggest that existing healthy eating policies will generate additional benefits to health and well-being, and that diet should be considered as a potential target for the prevention of depressive disorders.”
For More Information:
Dietary Pattern and Depressive Symptoms in Middle Age
Publication Journal: The British Journal of Psychiatry, 2009
By Tasnime N. Akbaraly, PhD; Eric J. Brunner, PhD; University College London, England and Institut National de la Santé et de la Recherche Médicale (INSERM), University of Montpellier, France
*FYI Living Lab Reports Are Summaries of the Original Research.