Can Polyphenols Have an Impact?

A review was recently published in a magazine. Antioxidant journal aimed at Understanding the impact of gut microbiota on brain aging.

study: Influence of the Gut Microbiota in Brain Aging: Polyphenols as Beneficial RegulatorsImage Credit: Lightspring/Shutterstock.com

Background

Brain aging is a complex physiological process characterized by cerebral vasculature, neuronal/glial dysfunction, and deterioration of brain repair systems. These dysregulations are caused by increased oxidative stress and pro-inflammatory conditions in the absence of antioxidant and anti-inflammatory systems. This condition is known as “inflammation”. Gut microbiota, gut-brain axis (GBA), and other intrinsic and extrinsic factors are related to brain function.

This study aimed to frame the existing picture of the influence of the gut microbiota on aging and to outline how polyphenols may be beneficial in regulating brain aging.

Effect of Gut Microbiota on Brain Aging

Gut microbes are key regulators of brain function, aging, and neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Key changes in the gut that affect aging are gut microbial symbiosis and changes in the gut barrier.

Moreover, pathogenic microbes and toxic agents lead to brain aging, with subsequent loss of beneficial gut microbes. Both human and animal model studies show that significant changes in microbial populations occur with age, leading to many adverse health conditions such as depression, cognitive impairment, and frailty.

Aging leads to an enrichment of certain gut microbiota, which accelerates the aging process and affects the functioning of vital organs, including the brain. Porphyromonas family Families are associated with the incidence of cognitive impairment.

some microorganisms such as those belonging to bacteroides family or species Faecalibacterium prausnitzii and Clostridium cluster XIVaassociated with reduced vulnerability in the elderly.

The characteristic age-related inflammatory state may be partially facilitated by age-related intestinal dysbiosis. For example, aging increases the proinflammatory state and decreases adaptive immune responses.

These factors accelerate the aging process and increase the risk of developing a variety of chronic diseases associated with central nervous system (CNS) dysfunction and adverse effects on brain health.

The gut/gut barrier and the blood-brain barrier (BBB) ​​are two barriers associated with GBA. The integrity of these two barriers is essential for axis function. The intestinal barrier is a semi-permeable tissue that allows only essential nutrients, and intestinal immune defenses restrict pathogenic molecules or microorganisms from the intestinal tract.

The intestinal barrier induces systemic tolerance to food antigens and fights pathogens. Disturbances in the gut/gut barrier cause inflammatory bowel disease, microbial infections, and food allergies, affect the inflammatory state of the body, and affect brain function. .

Regulation of brain aging by polyphenols synthesized by gut microbiota

The aging process is regulated by lifestyle factors such as the type of diet that interacts with the gut microbiota before reaching the brain. This is an important observation, as diet is an easily modifiable factor. Polyphenols are one of the most important anti-aging dietary components synthesized only by plants.

Polyphenols are found in plant-based foods and are potential anti-aging molecules. This metabolite crosses the BBB and exerts anti-inflammatory and antioxidant properties, which is why it has a particular impact on brain aging.

These properties positively affect cognitive and motor function, monoamine neurotransmitter conservation, and neurogenesis. Thus, polyphenols regulate brain homeostasis and prevent aging.

Before food constituent polyphenols cross the intestinal barrier and reach the brain, many interactions occur in the gut, affecting GBA and ultimately brain function and aging. All age-related changes in the gut, including inflammation and pathological conditions, affect polyphenol absorption and metabolism, affecting polyphenol arrival and brain function.

many in vitro, in vivoAlthough, human-based studies have been conducted to understand the effects of polyphenols in humans, the underlying mechanisms by which polyphenols modulate the gut microbiota and influence brain function are unclear.

Polyphenols affect the gut microbial population by affecting bacterial growth and metabolism. They promote the fortification of beneficial bacteria and limit the growth of harmful pathogens.

For example, in humans, polyphenols increase several beneficial bacteria such as: Flavonifractor plautii, Slackia equolifaciens, Slackia isoflavoniconvertens, Adlercreutzia equolifaciens, Eubacterium ramulus, Eggerthella lenta, Bifidobacterium spp., or Lactobacillus sppOf these, bifidobacteria seed. Contributes to intestinal barrier protection and reduces oxidative stress and inflammation.

Conclusion

These bacteria affect the brain through various mechanistic pathways. for example, Faecalibacterium prausnitzii It exhibits anti-inflammatory effects by inhibiting NF-κB activation, Lactic acid bacteria seed. Due to its high antioxidant activity, it plays a neuroprotective role in the gut microbiota. In most cases, the aforementioned bacteria prevent aging by blocking the inflammatory process.

Polyphenols also act as chelates for metal ions involved in reactive oxygen species (ROS) reactions, especially copper and iron. They can regulate redox metal homeostasis and prevent neurotoxicity, which is important in the prevention of neurodegenerative diseases. Polyphenols activate cellular stress response pathways and cause upregulation of neuroprotective genes.

Quercetin, a polyphenol, can suppress neuroinflammation by attenuating nitric oxide production. It also reduces the expression of the inducible nitric oxide synthase (iNOS) gene in microglia, preventing inflammatory cytokine production and neuronal damage. Therefore, changes in the gut microbiota affect different molecular pathways that influence brain aging.