Depression Linked to Processed Food
Mental Health Improves on a Diet of Fresh Ingredients
Nov 3, 2009
A group of researchers at the University College London set out to discover if diet could be a contributing factor in mental illness, particularly depression. They found it could.
Study Participants Divided into Two Groups
The results of the study have been published in the November 2009 issue of the British Journal of Psychiatry and describe data gathered from almost 3,500 people over a five-year period. The average age of the study group was 55, “in which two dietary patterns were identified: ‘whole food’ (heavily loaded by vegetables, fruits, and fish) and ‘processed food’ (heavily loaded by sweetened desserts, fried food, processed meat, refined grains, and high-fat dairy products).”
Lower Incidence of Depression in Whole Food Group
The study team says it controlled for factors such as age, smoking habits, gender, education, and physical activity.
Reporting on the study results, BBC News (November 2, 2009) says “Those who ate the most whole foods had a 26 percent lower risk of future depression than those who ate the least whole foods.
“By contrast people with a diet high in processed food had a 58 percent higher risk of depression than those who ate very few processed foods.”
Depression Assessed by Study Participants
The depression was self-reported by the people who took part in the study using data from Center for Epidemiologic Studies - Depression scale (CES-D). This scale is used widely and involves answering a questionnaire.
CES-D is described at medicalnewstoday.com as asking “a series of multiple choice questions about how the participant has been feeling over the past week, covering topics such as concentration, loss of appetite, worry, how well they have been able to shake off depressive moods, quality of sleep, feelings of loneliness, self-worth, energy levels, and so on.”
Several Explanations Offered in Depression Study
The researchers did not offer any single explanation for the findings. The news agency AFP (November 2, 2009) reported on what the team suggest may be going on:
“Firstly, the high level of antioxidants in fruits and vegetables could have a protective effect, as previous studies have shown higher antioxidant levels to be associated with a lower risk of depression.”
A second explanation may be the high levels in fish “of the sort of polyunsaturated fatty acids which stimulate brain activity.”
Amelia Hill, writing in The Observer (November 1, 2009) says, “Folate, which is found in large amounts in vegetables such as broccoli, cabbage and spinach, and foods such as lentils and chickpeas, may have the same effect.”
Dr. Archana Singh-Manoux, co-author of the report, is quoted as saying, “It could be because a processed food diet is associated with a higher risk of coronary heart disease and inflammation, which are known to be involved in the development of depression.”
More Study Needed
However, Dr. Singh-Manoux added that some lifestyle factors the team had not taken into account may be behind the results.
The research does not conclude that heavily processed foods cause depression. It’s possible that people who are likely to become depressed find some comfort in processed food and are therefore inclined to eat more of it than the rest of the population.
Further studies will be needed to sharpen the focus on what actually causes the link behind processed food and depression.
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