Probiotics and prebiotics may reduce the risk of frailty syndrome in older people

Probiotics and prebiotics may reduce the risk of frailty syndrome in older people

A recently published study in The Journal of Nutrition, Health and Aging found that the gut microbiome plays a critical role in metabolic processes that influence cognition, body composition and immune function. The joint modulation of these processes contributes to healthy aging.

Lernen: Neue Erkenntnisse zur Verwendung von Probiotika und Präbiotika zur Verbesserung der Darmmikrobiota älterer Erwachsener mit Frailty-Syndrom: Eine narrative Übersicht. Bildnachweis: Ground Picture/Shutterstock

background

Aging is characterized by low-grade chronic systemic inflammation resulting from the accumulated antigenic burden of “inflammation.”

Frailty syndrome, a multifactorial disease, is common in older people and causes significant functional impairment. The gastrointestinal tract plays a large role in the development of frailty syndrome. The syndrome can be attributed to pre-existing medical conditions, malnutrition, low physical activity, accumulation of cellular damage, uncontrolled inflammation, psychological changes, sociodemographic factors and polypharmacy. It can lead to adverse events including death if the patient is exposed to stressful conditions.

The gut microbiome affects the geriatric population, particularly those suffering from frailty syndrome. Aging alters the natural barrier of the gastrointestinal (GI) tract, allowing certain microbes and their metabolites to invade the systemic circulation, leading to inflammation.

In addition to food digestion and absorption, the gastrointestinal tract plays an important role in immune tolerance and serves as a habitat for commensal microbes. The gut microbiome includes viruses, bacteria and yeasts, and the proportion of their abundance could be specific to each individual. In humans, the bacterial strains Firmicutes and Bacteroides make up almost 90% of the gut microbiome.

Aging changes the gut microbiota, leading to many age-related diseases. However, the association of aging and gut microbiome with frailty syndrome remains unclear.

Probiotics are dietary supplements containing live microbes that modulate the gut microbiome by competitively inhibiting certain pathogenic species. These are available in different formulations and have different effects and target sites.

Prebiotics are insoluble carbohydrates that are primarily organic compounds but can also be obtained synthetically. They supply the intestinal microbiome with energy. Symbiotics contain substrates and living microorganisms that are beneficial to the health of the host. There are two types – complementary symbiotics, which target indigenous microorganisms, and synergistic symbiotics, in which substrates are selectively used by co-administered microorganisms. However, the health effects of symbiotics are still unclear.

The study

This study reviewed the influence of gut microflora on the health of older people and enumerated the possible interventions that could modulate the gastrointestinal microbiome, with a focus on patients with frailty syndrome.

Results

The gut microbiota is divided into three enterotypes; Bacteroides (family Bacteroidaceae), Prevotella (family Prevotellaceae), and Ruminococcus (family Ruminococcaceae) are the most abundant genera among the three enterotypes. The enterotypes that make up the main gut microbiome are roughly similar across different age groups.

However, training frequency, diet, diseases, age, antibiotic use, breastfeeding method, birth type, body mass index, intra- and extra-intestinal diseases and the anatomical environment influence the composition of the intestinal microbiota.

Some of these are individual host-related factors. The gut microbiome is also modulated by epithelial morphology, host genetic characteristics, epithelial immune components, use of prebiotics and probiotics, fecal transplantation, and exposure to external compounds.

Furthermore, the three major enterotypes of the gut microbiota become less abundant with age, altering host physiology. The gut microbiome produces short-chain fatty acids (SCFAs) – butyrate, acetate and propionate – through non-digestible monosaccharide fermentation. The SFCAs are absorbed into the systemic circulation in certain quantities and produce different local and systemic effects, particularly affecting the immune system.

Aging affects intestinal permeability, which further modifies the release of microbes and metabolites in the systemic circulation, thereby activating the immune system. Aging is influenced by the brain-gut axis and the gut microbiome, which in turn influences the gut microbiome through a bidirectional relationship.

The gut microbiome responds to stressors that influence the immune response. One example is the age-related changes in the hypothalamic-pituitary-adrenal (HPA) axis - visible in the changes in circadian cortisol levels.

The HPA axis changes are also evident in the changes in adrenocorticotropin hormone and cortisol responses in fragility syndrome. An altered gut microbiome likely causes the altered activation of the HPA axis, which triggers systemic inflammation.

Chronic inflammation affects dietary protein availability, implying the possibility of the existence of a gut-muscle axis. Decreased SCFAs in the geriatric population cause insulin resistance, which further leads to fat accumulation in muscles along with decreased muscle function. Therefore, changes in the gut microbiome lead to sarcopenic obesity.

Furthermore, alteration of gut microbiota leads to frailty due to malnutrition and age-related anorexia. SFCAs also alter bone metabolism through various mechanisms. SFCAs can be used to treat neurodegenerative diseases in the elderly and frail individuals.

Prebiotics are an effective preventative treatment because they improve the microbiota of the gastrointestinal tract, resulting in better nutrient absorption and maintenance of health. Probiotics are also an effective treatment for improving intestinal flora and reducing systemic inflammation. Probiotics can be prescribed to individuals with pre-existing comorbidities on various medications.

Malnutrition poses vascular risks and predisposes to cognitive weakness. Factors that exacerbate vascular risk impact cognitive problems associated with frailty syndrome. Frailty syndrome is characterized by a deficiency of almost all micronutrients; The risk of developing this syndrome increases in situations of micronutrient deficiency.

Micronutrient supplementation is easily possible; thus, this is a modifiable factor of the syndrome. Consuming antioxidants eliminates free radicals, thereby reducing oxidative stress that causes a decline in cognition. It has been found that low vegetarian protein intake and poor diet can increase the risk of frailty in older people (70-81 years).

Both sarcopenia and malnutrition can be treated with adequate energy and protein supplementation in the diet. Regular exercise and changes in diet can prevent frailty syndrome. Other interventional options to reduce frailty propensity include muscle building exercises following protein supplementation, leucine and vitamin D supplementation, dietary mineral and fiber intake, and creatinine supplementation. Although these are potential interventions for frailty syndrome, they do not directly target the gut microbiota.

Diploma

Diet and lifestyle changes can help maintain long-term healthy gut microbiota, which can contribute to healthy aging. Preventing malnutrition and improving the composition of the gut microbiome goes a long way in preventing frailty as we age. Probiotic and prebiotic supplements offer a modality for such an intervention.

Reference:

• Sánchez y Sánchez de la Barquera, B., Carrillo, BE, Garrido, JF, et al. (2022). Neue Erkenntnisse zur Verwendung von Probiotika und Präbiotika zur Verbesserung der Darmmikrobiota älterer Erwachsener mit Frailty-Syndrom: Eine narrative Übersicht. Das Journal für Ernährung, Gesundheit und Altern. https://link.springer.com/article/10.1007/s12603-022-1842-4

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