Researchers in London studied the dietary patterns of nearly 3,500 civil service office workers between the ages of 35 and 55. The subjects were followed in seven phases from 1985 to 2004. With many other factors accounted for, the scientists concluded there is a cause-effect relationship between poor dietary choices and depression. Based on results published in the November 2009 British Journal of Psychiatry, public health advocates will soon be recommending diets high in unprocessed foods for the purpose of preventing depression.
Two Diet Patterns Emerged
Subjects were asked about their consumption of 127 foods in 37 food groups. Anglicized meals, such as "fish and chips" were included, and Asian and black participants were eliminated from the results because of widely differing preferences. A "whole foods" pattern which included high intakes of fruit, vegetables and fish was compared to a "processed food" pattern that had high amounts of high fat dairy products, desserts, refined grains, processed meat and fried foods.
A Tool Measured Depression
Participants completed the Center for Epidemiologic Studies-Depression questionnaire, a tool for self-reporting depressive symptoms, five years later. Those with the highest intake of processed foods scored significantly more depression symptoms than those who ate the least processed foods.
Protective Nutrients Are Taken In the Context of Diet
Antioxidants, folate, and omega-3 fatty acids may be deficient in depressed persons and may be associated with improved moods. However, the London study did not try to determine the benefits of any single nutritional components.
Tasnime Akabaraly, Ph.D., the lead author of the study said, "In my opinion, the protective effect of diet on depression comes from a cumulative and synergistic effect of different nutrients from different sources of foods, rather than the effect of one isolated nutrient. If that's the case, it's important to assess the impact of overall diet on health outcome, because people don't eat isolated nutrients."
Doesn't Depression Cause Poor Dietary Choices?
Through sensitivity analysis, the authors of the study found no significant association between previous reports of depression and dietary patterns assessed six years later. In other words, depression did not predict dietary behavior. Additionally, the link between dietary patterns and depression remained unchanged even after excluding subjects with a prior history of depression. Results also did not alter significantly after adjusting for lifestyle factors such as exercise, smoking, and obesity.
Although this is a single study of middle-aged white office workers, the implications can be applied to other groups. A diet high in vegetables, fruits and fish is one part of a healthy lifestyle that may reduce the risk of depression even when other factors are accounted for.
References:
Akbaraly, TN, et.al., Dietary pattern and depressive symptoms in middle age, British Journal of Psychiatry, November, 2009, 195(5)
Mary Earhart - Mary Earhart, RN, BSN, is a Licensed Midwife. She has written articles for professional journals and grants for non-profit agencies as ...
Join the Conversation