Exploring the Impact of Flavonoids on Symptoms of Depression: A Systematic Review and Meta-Analysis

Abstract

Recent evidence suggests that diet modifies key biological factors associated with the development of depression. It has been suggested that this could be due to the high flavonoid content commonly found in many plant foods, beverages and dietary supplements. Our aim was to conduct a systematic review to evaluate the effects of dietary flavonoids on the symptoms of depression. A total of 46 studies met the eligibility criteria. Of these, 36 were intervention trials and 10 were observational studies. A meta-analysis of 36 clinical trials involving a total of 2788 participants was performed. The results showed a statistically significant effect of flavonoids on depressive symptoms (mean difference = −1.65; 95% C.I., −2.54, −0.77; p < 0.01). Five of the 10 observational studies included in the systematic review reported significant results, suggesting that a higher flavonoid intake may improve symptoms of depression. Further studies are urgently required to elucidate whether causal and mechanistic links exist, along with substantiation of functional brain changes associated with flavonoid consumption.

Hydroalcoholic Leaf Extract of Isatis tinctoria L. via Antioxidative and Anti-Inflammatory Effects Reduces Stress-Induced Behavioral and Cellular Disorders in Mice

“…Keeping in mind the knowledge that physical and mental stress activates cellular stress by intracellular pathways involved in increasing free radical production [50][51][52], we determined the effect of stress caused by immobilization as well as the effect of a single administration of IT on the level of ROS in the brain and the activity of antioxidant enzymes: SOD and CAT in brain and plasma. Our research showed that under the stress levels of antioxidant enzyme activity 14 Oxidative Medicine and Cellular Longevity were significantly leveled after a single administration of IT. The most significant changes were observed after a dose of 500 mg/kg body weight and 50 mg/kg b.w., which correlates with the results of behavioral studies, because, as described above, it was the use of these doses that had a significant effect in reducing the symptoms of stress.…”

“…Different nutraceuticals, including flavonoids, show antidepressant activities and may reduce stress-induced behaviors in animal models and humans as well [ 7 , 14 , 15 ].…”

Medicinal Plants and Their Impact on the Gut Microbiome in Mental Health: A Systematic Review

“…Clinical studies indicate that flavonoid consumption may ameliorate mental disorders such as depressive symptoms [ 222 ], but the mechanisms involved in these effects have not been fully elucidated. Some flavonoids are orally bioavailable and pass the BBB, and certain flavonoid groups show binding affinity for the benzodiazepine site on the GABA A receptor and inhibit monoaminoxidases A and B [ 223 ].…”

Possible Effects and Mechanisms of Dietary Natural Products and Nutrients on Depression and Anxiety: A Narrative Review

“…In a randomized trial of 24 healthy volunteers, consumption of yogurt twice daily after lunch and dinner did not significantly change biomarker levels of depression, but when the participants regularly consumed yogurt and daily exercised, the level of serotonin increased [ 102 ]. Additionally, a meta-analysis of 36 clinical trials including 2788 participants showed that the higher flavonoid consumption improved depressive symptoms (Mean difference = −1.65; 95% CI, −2.54, −0.77) [ 103 ]. Moreover, a meta-analysis of 23 randomized controlled trials including 237 participants revealed the saffron improved the symptoms of depression, compared with placebo [ 104 ].…”