Nutraceuticals and Physical Activity as Antidepressants: The Central Role of the Gut Microbiota

Abstract

Major depressive disorder (MDD) is a common mental illness. Evidence suggests that the gut microbiota play an essential role in regulating brain functions and the pathogenesis of neuropsychiatric diseases, including MDD. There are numerous mechanisms through which the gut microbiota and brain can exchange information in a continuous, bidirectional communication. Current research emphasizes the interexchange of signals influenced by the gut microbiota that are detected and transduced in information from the gut to the nervous system involving neural, endocrine, and inflammatory mechanisms, suggesting a relationship between oxidative stress and the pathophysiology of MDD via the hyperactivation of inflammatory responses. Potential sources of inflammation in the plasma and hippocampus of depressed individuals could stem from increases in intestinal permeability. Some nutraceuticals, such as specific probiotics, namely psychobiotics, polyphenols, carotenoids, butyrate, and prebiotics, have been demonstrated to exert an antidepressant activity, but most of them need to be metabolized and activated by gut microorganisms. By inducing changes in the gut microbiota composition, physical exercise might also exert a role in alleviating depression-like symptoms. The mutual relationships among nutraceuticals, exercise, and depression will be discussed, and the potential role of the gut microbiota as a therapeutic target to treat depression will be explored.

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

“…Pre-clinical studies suggest that phlorotannins have beneficial effects on gut microbiota, including improving structure, increasing SCFA levels, protecting intestinal cells, reducing obesity-related alterations, enhancing commensal bacteria growth, and potentially aiding in diabetes management [ 214 , 215 , 216 , 217 ]. Carotenoids, such as fucoxanthin and astaxanthin, found in various fruit and vegetables, may also help to improve gut health by modulating the gut microbiota and enhancing immune function, metabolic health, and gut barrier integrity, and may contribute antidepressant and neuroprotective effects through their antioxidant and anti-inflammatory properties [ 218 , 219 , 220 , 221 ]. More research is required, however, to better understand the potential properties of phlorotannins and carotenoids in a gut health context.…”

An Integrated Approach to Skeletal Muscle Health in Aging

“…There are numerous mechanisms through which the gut microbiota and brain can exchange information via continuous, bidirectional communication; the detection and transduction of information from the gut to the nervous system involve neural, endocrine, and inflammatory mechanisms [112].…”

Flavonols in Action: Targeting Oxidative Stress and Neuroinflammation in Major Depressive Disorder

“…Moreover, various inflammatory molecules originating from the gut microflora (lipopolysaccharides, endotoxins, etc.) may activate the peripheral immune system, reach the brain, activate microglia, and promote the development of depression through cytokine release [ 284 , 286 , 287 ]. The microbiota–inflammasome hypothesis of major depressive disorder states that the dysbiosis of the gut microbiota deteriorates the integrity of the blood–brain barrier through peripheral inflammation.…”

“…Among other contributing factors, the composition of the gut microflora is influenced by diet. In this regard, dietary polyphenols can modulate the intestinal microenvironment and functions of gut microbiota, which may affect the outcome of a therapeutic treatment [ 286 , 293 , 294 ]. On the other hand, polyphenols, including flavonols, need to be metabolized and activated by microorganisms in the gut.…”