
Introduction
Effects of Curcumin on the Brain
Inflammation, often referred to as “inflammaging,” is thought to increase with age; mounting evidence suggests that it can negatively impact the brain and cognitive health.4 Inflammation induction in rodents led to cognitive decline;4,5 other studies indicated that elevated pro-inflammatory cytokine levels are associated with decreased cognitive function.6 Curcumin has been shown to defend against neurodegeneration while promoting the growth of new neurons,7-10 which help combat the loss of brain volume. It can affect the levels of various brain neurotransmitters and, perhaps, aid in restoring their balance, which is lost as people grow older.9,11 Turmeric and curcumin have long been used for their anti-inflammatory properties.12-14

• Staying physically active
• Maintaining a healthy diet
• Getting adequate sleep
• Remaining socially connected
AD is characterized by the buildup of amyloid-beta protein plaques and tau protein-containing neurofibrillary tangles in the brain, which form lesions and interrupt cognitive functioning.
Curcumin has been used experimentally as a diagnostic tool for AD because of how well it binds to these plaques,19 providing more evidence that the supplement can cross, and interact with, the blood-brain barrier. It can also help break down or prevent plaque formation, shown in studies using a curcumin-treated AD mouse model.20
Evidence suggests that curcumin lowers amyloid-plaque levels by suppressing beta-secretase 1 (BACE1) expression,21 an enzyme that catalyzes the first step in their formation. It also accelerated the plaque clearance by increasing the expression of proteins necessary for the phagocytosis of those proteins.22 Macrophages taken from curcumin-treated patients with AD displayed an increase in the protein uptake.23
Curcumin may also benefit cognition by modulating the balance of the bacterial species in the microbiome. The human body coexists with about 100 trillion bacteria, mostly located in the gut. This population is made up of many species that are both good and bad for the body but must live in harmony with its organ systems, cells, and immune cells.
Microbiome dysbiosis occurs when this balance is disturbed (due to diet, illness, infection, antibiotic usage, and inflammation). This can agitate the “microbiota-gut-brain-axis,” an important system that involves the bidirectional communication between gut bacteria and the brain. Data show that this occurs in individuals with AD.27 Several studies have evaluated how curcumin affects the diversity of the microbiome in rodents. Overall, the supplement significantly increased the levels of beneficial Bifidobacteria and Lactobacilli, while decreasing the pathogenic Prevotellaceae, Coriobacterales, Enterobacteria, and Enterococci bacteria.28
References
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