The mechanism of probiotics in preventing common diseases in the elderly.

In the past few decades, although the global average lifespan has been significantly extended, the health status of the elderly has not improved correspondingly, leading to many socio-economic problems. Human health mainly depends on the interaction between genetic factors and environmental factors (such as diet and lifestyle). Among them, the gut microbiome can affect the body's immune response to pathogens, nutrient absorption, and energy expenditure. The gut microbiome is formed within 1 to 3 years after birth and can change due to food, stress, antibiotic treatment, and aging. The gut microbiome interacts with the nervous, musculoskeletal, and cardiovascular systems, so regulating the gut microbiome may be a key factor in preventing or treating various age-related diseases.^[1]Probiotics can play a key role in regulating the gut microbiome, controlling metabolism, resisting infections and inflammation, preventing autoimmune diseases and cancer, and regulating the gut-brain axis.

1. The preventive effect of probiotics on Alzheimer's disease

Alzheimer's disease is a neurodegenerative disease, and various aspects of its pathophysiology are still under research. It is characterized by a gradual decline in cognitive function and the loss of specific types of neurons and synapses. Some believe that Alzheimer's disease may be related to malnutrition of the microbiome in the gut, based on the hypothesis that gut microbiota can produce substances such as monoamines and amino acids, which reach central neurons through the lymphatic and vascular systems, potentially affecting behavior.^[2]Clinically, it has been proven that chronic Helicobacter pylori and other synergistic effects can induce infections in the brains of Alzheimer's patients.

PISTOLLATO et al.^[3]Investigated the effects of certain diets on Alzheimer's disease. The results indicated that a healthy diet characterized by high intake of probiotics, prebiotics, and other nutrients can delay the decline of neurocognitive function and reduce the risk of Alzheimer's disease. Additionally, AKBARI et al.^[4]Research shows that probiotic supplementation not only affects normal brain activity but also significantly improves cognition in Alzheimer's patients.

2. The preventive effect of probiotics on osteoporosis

Estrogen plays a major role in promoting bone formation. It can directly inhibit the activity and lifespan of osteoclasts, promote the differentiation of osteoblasts, or reduce the apoptosis of mature osteoblasts. The gut microbiome can act as an 'endocrine organ' by utilizing exogenous nutrients to produce more estrogen. Current studies have used a primary osteoporosis model in specific pathogen-free mice, using ovarian steroid inhibitors (leuprolide) in germ-free mice. Mice were treated with Lactobacillus rhamnosus GG (LGG) or the commercially available probiotic supplement VSL#3 (which contains 4 strains of lactobacilli, 3 strains of bifidobacteria, and Streptococcus thermophilus). Compared to the untreated control group, both LGG and VSL#3 significantly prevented the reduction of femoral density, trabecular thickness, and quantity in the two models. Importantly, non-probiotics, such as Escherichia coli DH5alpha and LGG fimbrial mutants [LGG(ΔSpaC)], did not provide any protection against bone loss.

3. The preventive effect of probiotics on cardiovascular diseases

Elevated low-density lipoprotein cholesterol is one of the main factors in cardiovascular diseases. The accumulation of low-density lipoprotein cholesterol in the blood is a precursor to hypertension and hyperlipidemia and can lead to the formation and accumulation of atherosclerotic plaques. GRUNDY^[5]conducted an analysis of randomized controlled clinical trials, summarizing data from a total of 485 participants with 'high', 'slightly high', and 'normal' serum cholesterol levels. The findings showed that consuming probiotics significantly reduced low-density lipoprotein cholesterol and total cholesterol levels in all categories compared to the control group. Hypertension is closely related to hypercholesterolemia and is one of the main risk factors for cardiovascular diseases. DONG et al. [6] studied 702 hypertensive patients, conducting a clinical trial with 14 randomized placebo-controlled analyses, which indicated that probiotic fermented milk could significantly reduce systolic and diastolic blood pressure in prehypertensive and hypertensive patients. Therefore, consuming probiotics can lower cholesterol and hypertension, reducing the risk of coronary heart disease, atherosclerosis, heart attacks, and strokes by nearly half.

In summary, gut probiotics may be important regulatory factors in the development of age-related diseases, affecting brain, bone, and cardiovascular health, thereby influencing the occurrence of Alzheimer's disease, osteoporosis, and cardiovascular diseases. Although exercise and diet are important for preventing these diseases, combining them with interventions that add diverse probiotics may be an effective way to maintain the health of the elderly and prevent age-related diseases.

References:

[1] LAKSHMINARAYANAN B, STANTON CO, TOOLE PW, et al. Compositional dynamics of the human intestinal microbiota with aging: implications for health [J] J Nutr Health Aging, 2014, 18(9): 773–786.

[2] VIÑA J, SANZ RJ. Alzheimer’s disease: Only prevention makes sense [J]. Eur J Clin Invest, 2018, 48(10): e13005.

[3] PISTOLLATO F, IGLESIAS RC, RUIZ R, et al. Nutritional patterns associated with the maintenance of neurocognitive functions and the risk of dementia and Alzheimer’s disease: A focus on human studies [J]. Pharmacol Res, 2018, (12): 15–20.

[4] AKBARI E, ASEMI Z, KAKHAKI RD, et al. Effect of probiotic supplementation on cognitive function and metabolic status in Alzheimer’s disease: A randomized, double-blind and controlled trial [J]. Front Aging Neurosci, 2016, (12): 15–24.

[5] GRUNDY SM. Promise of low-density lipoprotein-lowering therapy for primary and secondary prevention [J]. Circulation, 2008, (117): 569–573. [6] DONG JY, SZETO IM, MAKINEN K. Effect of probiotic fermented milk on blood pressure: A meta-analysis of randomised controlled trials [J]. Br J Nutr, 2013, (110): 1188–1194.

Note: This article is for informational purposes only and should not be considered medical advice.