Do Inflammatory Diets Cause Depression?
Depression affects over 300 million people around the world, and it’s quite possible that diet plays a part.
While depression was long thought to be a matter of imbalances in brain chemistry, inflammation may contribute even more to the risk for symptoms. And the primary cause of that inflammation may come from the very foods that people eat every day.
This review investigated the link between diets and inflammation and considered their effects on states of mind. Evaluating eleven clinical studies, encompassing over 100,000 participants, ranging from 16 to 72 years old, researchers found a significant link between a pro-inflammatory diet and increased risk of depressive symptoms or a diagnosis of the condition.
Researchers also noted that the results of these studies could vary widely. For example, in one case, pro-inflammatory diets increased the risk of depression in women, but not men, while others found exactly the opposite. Additionally, some studies included only specific populations or age groups, so it could be difficult to apply the results across the board.
However, some areas of agreement center around the kinds of nutrients supplied by certain foods, including choline and betaine for lowering peripheral inflammatory levels and other markers of inflammation including C-reactive protein, IL-6, and tumor necrosis factor alpha (TNF-a).
The bottom line appears to be, as expected, that what we eat intensively affects the health of the body and mind. While some people may have more flexibility regarding their intake of refined foods and sugars, ultimately, a diet may make the difference for anyone struggling with depression.
Abstract:
Tolkien K, Bradburn S, Murgatroyd C. An anti-inflammatory diet as a potential intervention for depressive disorders: A systematic review and meta-analysis. Clin Nutr. 2019 Oct;38(5):2045-2052. doi: 10.1016/j.clnu.2018.11.007. Epub 2018 Nov 20. PMID: 30502975.
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.
Methods: 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.
Results: 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).
Conclusion: 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.
