Ezhuthachan College of Pharmaceutical Sciences, Marayamuttom, Thiruvananthapuram
Older adults are particularly prone to a variety of health challenges, such as weakened immune function, digestive problems, chronic inflammation, and a heightened risk of infections. These issues often lead to a reduced quality of life, with symptoms like fatigue, poor nutrition, and increased vulnerability to disease. As people age, the composition of the gut microbiota essential for digestion, nutrient absorption, and immune regulation undergoes significant shifts. These changes can disrupt the balance of beneficial gut bacteria, a condition known as dysbiosis. The gut microbiota, which plays a crucial role in digestion, nutrient absorption, and immune regulation, undergoes significant changes with age, often leading to dysbiosis or an imbalance of gut bacteria. Probiotics, which are live beneficial microorganisms like certain bacteria and yeasts, have been shown to support gut health by helping restore this microbial balance. They can also aid in digestion, enhance immune responses, and potentially improve both mental and physical health, especially in older adults. With the global aging population on the rise, there’s an urgent need to identify strategies that support better health and well-being among the elderly. This study focuses on evaluating the role of probiotics in enhancing digestive health, cognitive performance assessed using the BASIC Q scale and immune function, as measured through specific biochemical markers in the geriatric population.
The geriatric population typically defined as individuals aged 65 and above experiences a natural and gradual decline in physiological function, a process known as senescence. [1] Aging is marked by a progressive loss of biological integrity, which can lead to functional impairments and an increased risk of mortality. [2] One of the notable changes in older adults is the reduction in gut microbiota diversity and abundance when compared to younger adults.[3] This decline is linked to a higher risk of gastrointestinal disorders like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), as well as systemic conditions such as allergies and asthma.[4] Most of the gut microbiota resides in the colon, and its composition can vary significantly across different sections of the intestine even within the same person.[5] The gut microbiome plays a critical role in transmitting environmental signals and supporting key physiological functions, including immune regulation, [10,11] metabolism, [10,12] and neural communication [8,9]. These microbes help protect against diseases, particularly those associated with aging. However, in healthy elderly individuals, there is often a decrease in beneficial bacterial strains like Bifidobacterium and Lactobacillus, coupled with an increase in pro-inflammatory organisms such as Enterobacteriaceae.
GERIATRIC POPULATION
Geriatric population are population of 65 years and older. This group is characterized by age related physiological, functional and cognitive changes that influence their health care needs.[13]
The geriatric population can be further categorized based on age:
As people age, their bodies undergo changes that affect how medications are absorbed, distributed, metabolized, and excreted alterations known as changes in pharmacokinetics. In addition, aging also impacts pharmacodynamics, which concerns how drugs interact with the body, including their effects and mechanisms of action. These changes require healthcare providers to be cautious when prescribing medications to older adults to avoid adverse effects. [13,14,15]. Numerous studies have demonstrated that probiotics can enhance cognitive abilities, boost immune function, support digestive health, and improve microbial diversity. Additionally, they may help reduce the frequency of infections and common colds, contributing to an overall better quality of life in older adults. [13,14,15]
PROBIOTICS
Probiotics are live bacteria or yeasts that offer health benefits when consumed in appropriate amounts, primarily by supporting a healthy balance in the gut microbiota. They contribute to digestive well-being, enhance immune defences, help combat harmful microbes and toxins, and may even influence mood and memory [16,21] Mechanistically, probiotics work by lowering gut pH, producing antimicrobial substances, and outcompeting harmful pathogens for nutrients and binding sites in the intestine. They also activate immune-modulating cells and help produce lactose and other metabolites that support gut health. Certain strains, such as Lactobacillus, can adhere to the gut lining, preventing colonization by pathogens and reinforcing the immune system. These bacteria also stimulate the production of short-chain fatty acids, which help maintain a healthy intestinal environment. [17,19,20,21]
The effects of probiotics vary with the difference in strain, dosage and duration of supplementation. It has rare side effects like mild Bloating or gas may occur initially, constipation if used (prolonged), headache, thirst.[21]
IMPACT OF PROBIOTICS IN COGNITIVE FUNCTIONS OF ELDERLY
As individuals age, there is a natural decline in central nervous system function, often resulting in cognitive deterioration and mood-related issues.[23] This growing risk of neurological disorders in older adults has led to increased focus on preventive and therapeutic strategies aimed at supporting healthy brain aging. [22,23] One key player in this area is the gut microbiota a diverse community of beneficial microorganisms that significantly influence various physiological processes, including immune regulation and brain function. In recent years, mounting evidence has highlighted the gut-brain axis (Figure 1), a complex bidirectional communication network that connects the gastrointestinal tract with the central nervous system through neural, hormonal, and immune pathways.[23] Probiotics live microorganisms with health-promoting properties have shown promising effects on cognitive health, particularly in older adults. Their beneficial impact on cognition is primarily attributed to their role in modulating the gut-brain axis. Several mechanisms (Figure 2) explain how probiotics may support brain function:
Benefits of Probiotics for Brain Health
Figure 1 GUT- BRAIN AXIS
BASIC-Q: A Tool to Assess Cognitive Impairment
The Brief Assessment of Impaired Cognition Questionnaire (BASIC-Q) is a quick and user-friendly tool designed to identify early cognitive decline in older adults. It integrates self-reported concerns, input from family or caregivers, and simple orientation questions to assess mental function. This tool is particularly useful in both clinical and community settings for early detection of cognitive issues. [24,31,32]
IMPACT OF PROBIOTICS IN IMPROVING THE DIGESTIVE HEALTH OF ELDERLY
Probiotic supplementation has demonstrated several beneficial effects on the digestive system of older adults, primarily through multiple interconnected mechanisms (Figure 2):
Balancing Gut Microbiota: With age, the diversity and stability of gut microbiota often decline, leading to dysbiosis disruption in the balance between beneficial and harmful microorganisms. This imbalance is linked to various digestive and systemic disorders. Probiotics help re-establish a healthier microbial composition by promoting beneficial strains such as Lactobacillus (e.g., acidophilus, plantarum), Bifidobacterium (e.g., bifidum, longum), and Saccharomyces boulardii, while simultaneously suppressing harmful bacteria. This microbial rebalancing supports more efficient digestion and nutrient absorption.[30] Strengthening the Gut Barrier: Probiotics enhance the integrity of the intestinal lining by promoting mucus secretion and tightening junctions between epithelial cells. This fortified barrier prevents the entry of pathogens and toxins into the bloodstream, thereby reducing systemic inflammation and infection risk.[35] Lowering Gut pH: Certain probiotic strains acidify the intestinal environment by producing organic acids. This lowered pH inhibits the growth of harmful microbes while fostering the proliferation of beneficial bacteria.[35] These combined actions can significantly improve the digestive well-being of elderly individuals, addressing common gastrointestinal issues such as constipation, diarrhea, and gastric discomfort. [34,35,36] Constipation Relief: Strains like Bifidobacterium and Lactobacillus have shown promise in relieving chronic constipation by promoting regular bowel movements and improving intestinal motility, though effectiveness may vary among individuals. [34] Managing Diarrhea: Probiotics, especially during and after antibiotic use, can reduce the frequency and duration of diarrhea, including antibiotic-associated diarrhea, which is particularly prevalent in older adults. [37,38] Reducing Gastric Irritation: Probiotics may help mitigate symptoms of irritable bowel syndrome (IBS), including bloating and discomfort, by reducing inflammation, enhancing mucosal integrity, and normalizing gut motility. [34]
IMPACT OF PROBIOTICS IN IMMUNE FUNCTIONS OF ELDERLY
As people age, immune function naturally declines, making older adults more susceptible to infections and inflammatory diseases.[39] Probiotics are live beneficial microbes can positively influence immune health, particularly by interacting with the gut-associated lymphoid tissue (GALT), a major component of the immune system located within the intestinal lining. [40,48] The key mechanisms (Figure 2) of Immune Modulation are;
Microbiota Regulation: Aging alters gut microbiota composition, weakening immune responses. Probiotics help diversify the gut microbiota, which supports a more robust and balanced immune function while lowering chronic inflammation. [41,45] Enhancing Innate Immunity: Certain probiotic strains, such as Lactobacillus casei Shirota, have been found to boost the activity of natural killer (NK) cells critical defenders against pathogens thereby reinforcing the body's first line of immune defence. [42,43] Anti-inflammatory Action: Probiotics can promote the production of anti-inflammatory cytokines like IL-10 and TGF-β, while suppressing pro-inflammatory signals. This balance is vital in preventing age-related chronic inflammation. [40,46] Activation of T Regulatory Cells: These cells play a crucial role in maintaining immune tolerance and preventing autoimmune responses. Probiotics support their activation, helping to preserve immune homeostasis. [44]
BIOCHEMICHAL MARKERS OF IMMUNE RESPONSE
Probiotics also influence key biochemical markers that reflect immune status in the elderly.[47] C-Reactive Protein (CRP): A marker of systemic inflammation, CRP levels tend to rise with age and chronic disease. Probiotic use has been associated with reduced CRP levels, indicating lowered inflammation. [47]
Erythrocyte Sedimentation Rate (ESR): Elevated ESR is another sign of chronic inflammation. Probiotic supplementation has been shown to help reduce ESR values. [47,48] Polymorphonuclear Leukocytes (PMNs): These white blood cells are essential in defending against bacterial infections. Probiotics enhance their function, improving the immune system's ability to fight pathogens. [49] Lymphocytes: Comprising T cells, B cells, and NK cells, lymphocytes are key to adaptive immunity. Probiotics have been found to boost both their proliferation and effectiveness. [47,49] Total White Blood Cell (WBC) Count: Maintaining optimal WBC levels is crucial for effective immune surveillance. Probiotics help regulate WBC count to ensure adequate immune response without triggering unnecessary inflammation. [47,50] In summary, probiotics offer a multifaceted approach to improving immune and digestive health in older adults. By modulating gut microbiota, strengthening intestinal and immune barriers, and regulating inflammation, probiotics support better health outcomes and contribute to healthier aging.
Figure 2 Mechanism of action of probiotics
DISCUSSION
Based on the evidences mentioned in the table 1 the topic was reviewed;
A Randomised Controlled Trial, Meta Analysis by Man Jiang etal; (2024) Effect of Probiotics on Cognitive Function in Adults with Mild Cognitive Impairment or Alzheimer's Disease reveals that probiotics significantly improved cognitive function in individuals with mild cognitive impairment and Alzheimer's disease. The findings suggested that probiotic supplementation, particularly strains of Lactobacillus and Bifidobacterium, contributed to enhanced memory, executive function, and overall cognitive performance.[51] A Randomized, Double-Blind, Placebo-Controlled Trial by Lewis et al. (2020) Investigating a Probiotic Blend on Supporting Digestive Health in Older Adults with Occasional Constipation. The results indicated a significant improvement in bowel movement frequency and stool consistency in the probiotic group compared to placebo (p<0.05). Additionally, participants reported enhanced overall digestive comfort. The study concluded that probiotic supplementation could be a beneficial, non-pharmacological approach for managing constipation in older adults.[52] A Randomized, double-blind, placebo-controlled trial Castro-Herrera etal. (2022) Combination of the Probiotics Lacticaseibacillus rhamnoses GG and Bifidobacterium animalis subsp. lactis, BB-12 Has Limited Effect on Biomarkers of Immunity. The findings revealed that there is a significant change in key immune markers, such as cytokine levels and immunoglobulin responses, suggesting a significant effect on systemic immunity.[53]
CONCLUSION
Overall, probiotics may support better cognitive function, digestion, and immune health in older adults, especially when used alongside treatments for other existing health conditions. The benefits can differ depending on the specific strains used, how long they're taken, and the dosage. Including probiotics in the care of the elderly could enhance their overall quality of life, but more research is needed to deepen our understanding and drive further progress in this area.
REFERENCES
Amina S. N., Ardra S. A., Sam Jeeva Kuma, Chintha Chandran*, Shaiju S. Dharan, A Review on Impact of Probiotics in Improving Cognitive Function, Digestive Health & Immune Response of Geriatric Population, Int. J. of Pharm. Sci., 2025, Vol 3, Issue 5, 1754-1763. https://doi.org/10.5281/zenodo.15382963
10.5281/zenodo.15382963
