Increased Antioxidant Consumption Associated with Improved Depression and Anxiety Symptoms

by | Mar 27, 2023 | Antioxidants, Brain Health, Depression

Written by Taylor Woosley, Staff Writer. Results of the meta-analysis including 52 RCTs and 4049 subjects shows a statistically significant improvement in depressive status after taking antioxidant supplements (p < 0.00001). 

depressionMajor depressive disorder (MDD) is one of the most common mental illnesses as it affects more than 350 million people globally1. MDD is considered a multifactorial disease characterized by a loss of motivation or pleasure, feelings of guilt, difficulty concentrating, and fatigue2. Despite the high prevalence rate of MDD, the illness remains both underdiagnosed and undertreated3.

Increasing evidence suggests that the presence of oxidative stress and disorders of the antioxidant defense system are involved in a wide range of neuropsychiatric disorders4. Depression also results in reduced levels of antioxidants and may contribute to an impaired defense against free radicals5. Improving antioxidant levels can aid in repressing the oxidative stress pathway, removing the reactive oxygen species (ROS) that may cause harm to neurons in the brain, and leading to a reduction in the symptoms of anxiety and depression6.

Wang et al. conducted a meta-analysis of randomized clinical trials (RCTs) to analyze the effects of a variety of antioxidant supplements on depression and anxiety. Inclusion criteria consisted of being an original research article in English, RCTs comparing antioxidant intervention and a control group in human, and studies that reported depression scores at baseline and end of intervention. In addition to grouping different types of antioxidant supplements, they conducted subgroup analysis for different scales and studies in different countries to achieve the role of sensitivity analysis. The final meta-analysis included 52 studies, including 22 studies (42.3%) on antioxidant minerals. A total of 4049 subjects were included, of whom 2004 participants were treated with antioxidant supplements and 2045 subjects were treated with a placebo or nothing. Median treatment duration was 11 (8, 12) weeks. All studies assessed the depressive status of the participants, and 21 studies (40.4%) reported the anxiety status.

Heterogeneity was analyzed by Cochran’s Q statistic and the I2 statistic. Fixed-effects models were used for meta with no or low heterogeneity (I2 < 50%, p > 0.1), and random-effects models were used for meta with moderate or high heterogeneity (I2 ≥ 50%, p ≤ 0.1). Significant findings of the study are as follows:

  • The meta-analysis showed a statistically significant improvement in depressive status after taking antioxidant supplements (SMD = 0.60; 95% CI: 0.40, 0.81, p < 0.00001).
  • A subgroup meta-analysis of nine RCTs that reported depression scores before and after zinc supplementation shows that zinc supplementation could significantly improve depression status (SMD = 0.59; 95% CI: 0.13, 1.05, p = 0.01).
  • A subgroup meta-analysis of eight RCTs reporting the effects of magnesium supplementation resulted in significant improvements in depressive status after consuming magnesium supplements (SMD = 0.16; 95% CI: 0.01, 0.31, p = 0.03).
  • A subgroup meta-analysis of eight studies using a complex of antioxidant supplementation showed that multiple antioxidant co-supplementation also significantly improved depressive status (SMD = 0.85; 95% CI: 0.19, 1.51, p = 0.01).

Results of the meta-analysis demonstrate that supplementing with antioxidants, such as zinc and magnesium, can significantly improve depressive status. Furthermore, findings of the meta-analysis show that intake of antioxidant supplements significantly improved anxiety status. Study limitations include the lack of adding more granular groupings of participants and the need for further research on the positive effects of antioxidants on anxiety states.

Source: Wang, Huan, Mengdi Jin, Mengtong Xie, Yuqing Yang, Fengyu Xue, Weizhen Li, Min Zhang et al. “Protective role of antioxidant supplementation for depression and anxiety: A meta-analysis of randomized clinical trials.” Journal of Affective Disorders (2022).

© 2022 Published by Elsevier B.V.

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Posted March 23, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

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