Summary: Researchers confirm the link between eating junk foods, which are known to promote inflammation, and an increased risk of depression. To combat depressive symptoms, the study reports people should switch to a Mediterranean style diet.
Source: Manchester Metropolitan University.
A diet of fast food, cakes and processed meat increases your risk of depression, according to researchers at Manchester Metropolitan University.
A paper from Manchester Metropolitan’s Bioscience Research Centre found that eating a diet containing foods which are known to promote inflammation – such as those high in cholesterol, saturated fats and carbohydrates – makes you around 40% more likely to develop depression.
The researchers analysed data from 11 existing studies that focused on the link between depression and pro-inflammatory diets – encompassing more than 100,000 participants of varied age (16-72 years old), gender and ethnicity, spanning the USA, Australia, Europe and the Middle East.
All the studies recorded the presence of depression or depressive symptoms in the participants (through self-observation, medical diagnoses and/or antidepressant use), alongside a detailed questionnaire about the contents of their diet.
Each participant was assigned a score of how inflammatory his or her diet is, according to the dietary inflammatory index.
Some of the studies were cross-sectional, using data that was immediately available, and other studies tracked participants for up to 13 years.
Across all studies, participants who had a more pro-inflammatory diet were, on average, 1.4 times more likely to have depression or depressive symptoms.
The results were consistent regardless of age or gender – and were the same over both short and long follow-up periods.
Dr. Steven Bradburn is from the Bioscience Research Centre at Manchester Metropolitan’s School of Healthcare Science. He said:
“These results have tremendous clinical potential for the treatment of depression, and if it holds true, other diseases such as Alzheimer’s which also have an underlying inflammatory component.
“Simply changing what we eat may be a cheaper alternative to pharmacological interventions, which often come with side-effects.
“This work builds on recent advances in the field by others, including the first ever clinical trial into dietary interventions for treating depression, which have shown beneficial improvements in depressive symptoms.
“It should be stressed, however, that our findings are an association, rather than causality. Further work is needed to confirm the efficacy of modulating dietary patterns in treating depression with relation to inflammation.”
An anti-inflammatory diet—containing more fibre, vitamins (especially A, C, D) and unsaturated fats—has the opposite effect, and could be implemented as a treatment for depression.
Therefore, a Mediterranean diet of olive oil, tomatoes, green vegetables and fatty fish could help lower depressive symptoms.
Inflammation is the body’s natural defense system against infections, injuries and toxins. In order to protect itself from harm, the body releases proteins, antibodies and increased blood-flow to affected areas, causing redness and swelling.
However, chronic inflammation puts the body in a constant state of alert and has previously been linked to diseases such as cancer, asthma and heart disease. Such persistent inflammation, particularly in the brain, is believed to contribute to neuronal death.
Source: Manchester Metropolitan University
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Original Research: Open access research for “An anti-inflammatory diet as a potential intervention for depressive disorders: A systematic review and meta-analysis” by Katie Tolkien, Steven Bradburn, and Chris Murgatroyd in Clinical Nutrition. Published December 18 2018.
An anti-inflammatory diet as a potential intervention for depressive disorders: A systematic review and meta-analysis
Background & aims
There is a large body of evidence which supports the role of inflammation in the pathophysiology of mental health disorders, including depression. Dietary patterns have been shown to modulate the inflammatory state, thus highlighting their potential as a therapeutic tool in disorders with an inflammatory basis. Here we conduct a systematic review and meta-analysis of current literature addressing whether there is a link between the inflammatory potential of a diet and risk of depression or depressive symptoms.
A systematic literature search was performed to identify studies that reported an association between the inflammatory potential of the diet and risk of depressive symptoms or diagnosis of depression. Random effect models were used to meta-analyse effect sizes. Quality assessment, publication bias, sensitivity and subgroup analyses were also performed.
Eleven studies, with a total of 101,950 participants at baseline (age range: 16–72 years old), were eligible for review. A significant association between a pro-inflammatory diet and increased risk of depression diagnosis or symptoms was evident, relative to those on an anti-inflammatory diet (OR: 1.40, 95% confidence intervals: 1.21–1.62, P < 0.001). No publication bias was detected; however, some study heterogeneity was evident (I2 = 63%, P < 0.001). Subgroup analyses suggested the main source of study heterogeneity was the study design (cross-sectional or longitudinal) and the effect measure used (odds ratio, hazard ratio or relative risk).
These results provide an association between pro-inflammatory diet and risk of depression. Thus, adopting an anti-inflammatory diet may be an effective intervention or preventative means of reducing depression risk and symptoms.