As the aging population grows, Alzheimer’s disease (AD) has become a major global health concern.
According to data from the World Health Organization, over 55 million people worldwide currently suffer from dementia. It is estimated that by 2050, this number will rise to nearly 140 million.
The China Alzheimer Report 2024 reveals that the number of individuals in China diagnosed with Alzheimer’s and other forms of dementia has reached approximately 17 million, accounting for nearly 30% of the global dementia population.
In recent years, research has uncovered intricate connections between gut microbiota and Alzheimer’s disease.
Today, we invite Dai Wenxin, Director of the Multidisciplinary Geriatrics Center at Hainan Chengmei Hospital, to provide insights into the relationship between Alzheimer’s disease and gut microbiota, as well as how regulating gut health may help slow disease progression.
I. Alzheimer’s Disease: The “Silent Killer” of Elderly Health
Alzheimer’s disease is a progressive neurodegenerative disorder characterized by memory decline, cognitive impairment, and abnormal behaviors.
The risk of developing AD significantly increases with age. Statistics show that among people over 65, the incidence rate nearly doubles every five years.
Currently, the exact cause of Alzheimer’s disease remains unclear, but studies suggest that genetic factors, environmental influences, and lifestyle choices all play a role in its development.
II. Gut Microbiota: The “Second Commander” of Brain Health
Gut microbiota refers to the trillions of microorganisms residing in the human gut. These microbes not only aid digestion, absorption, and immune regulation but also communicate bidirectionally with the brain through the gut-brain axis.
The gut-brain axis is a complex network involving the nervous, endocrine, and immune systems. Gut microbiota influence brain function by producing metabolic byproducts such as short-chain fatty acids (SCFAs) and neurotransmitters, which affect mood, cognition, and behavior.
Recent research has revealed a direct link between gut microbiota and Alzheimer’s disease (AD). Studies indicate that the composition of gut microbiota in AD patients differs significantly from that of healthy individuals. AD patients often have a reduced population of beneficial bacteria (e.g., Bifidobacteria and Lactobacilli) and an increase in harmful bacteria (e.g., Escherichia coli and Clostridia). This microbial imbalance can lead to compromised gut barrier function, triggering systemic inflammation that accelerates neuronal damage and contributes to Alzheimer’s disease progression.
III. How Does Gut Microbiota Influence Alzheimer’s Disease?
Inflammatory Response: Gut dysbiosis increases gut permeability (commonly referred to as “leaky gut”), allowing bacterial toxins and inflammatory mediators to enter the bloodstream. This systemic inflammation may affect the brain via the blood-brain barrier, promoting β-amyloid plaque buildup and neuronal damage.
Metabolic Regulation: Beneficial gut bacteria produce short-chain fatty acids (SCFAs) such as butyrate and propionate, which have anti-inflammatory and neuroprotective effects. An imbalance in gut microbiota reduces these protective compounds, exacerbating brain inflammation and neuronal degeneration.
Neurotransmitter Production: Gut microbiota plays a crucial role in synthesizing neurotransmitters such as serotonin, dopamine, and gamma-aminobutyric acid (GABA), which are essential for mood and cognitive function. Dysbiosis can disrupt neurotransmitter balance, negatively affecting brain function.
IV. How to Regulate Gut Microbiota to Slow Alzheimer’s Disease Progression?
Fecal Microbiota Transplantation (FMT): Transplanting gut microbiota from a healthy donor into an AD patient can help restore microbial balance and improve gut health.
Dietary Interventions: Elderly individuals are advised to consume more fiber-rich foods (such as whole grains, vegetables, and fruits) to promote the growth of beneficial gut bacteria. Additionally, moderate intake of fermented foods (such as yogurt and kimchi) can help maintain gut microbiota balance.
Regular Physical Activity: Studies show that moderate exercise enhances gut microbiota diversity and promotes the growth of beneficial bacteria. Seniors can engage in low-impact exercises such as walking or Tai Chi to improve overall and gut health.
Avoid Overuse of Antibiotics: Antibiotics, while eliminating pathogenic bacteria, can also disrupt the balance of gut microbiota. Elderly individuals should use antibiotics appropriately under a doctors guidance to avoid drug abuse.
Expert Recommendations
Preventing and managing Alzheimer’s disease requires a comprehensive approach. In addition to gut health, individuals over 50 years old should undergo regular cognitive function screenings. Early detection and intervention are key to slowing disease progression.
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Editor | Huang Fei