One of the problems when it comes to a person getting older is the progressive frailty that accompanies them later in life. Frailty from aging results in issues involving the failure of various physiological functions and systems, including but not limited to the development of chronic low-grade inflammation, loss of cognitive function, and the development of chronic diseases like diabetes and atherosclerosis. To slow the decline associated with age-related frailty, scientists have suggested modifications of dietary patterns, such as switching to a Mediterranean diet (MedDiet). This diet is characterized by increased consumption of vegetables, legumes, fruits, nuts, olive oil, and fish. Additionally, the MedDiet requires low consumption of red meat, dairy products, and saturated fats.
Previous studies have supported the beneficial nature of the MedDiet, associating it with reduced mortality, increased antioxidant activity, reduced incidences of several diseases, and reduced inflammation. On top of these benefits, the MedDiet has been associated with beneficial changes in the gut microbiome. Studies have supported that this diet reduces the presence of proteobacteria while increasing levels of short-chain fatty acid production. The potential positive effects of the MedDiet on the health of the gut microbiome are significant in frail elderly patients, who often have insufficient function of the gut microbiome due to improper restricted diets.
The NU-AGE Dietary Intervention project aims to investigate the controlled consumption of a Mediterranean diet over 12 months on frail elderly patients to determine the effects on biodiversity of their inadequate gut microbiome. The NU-AGE dietary intervention project studied the effects of a customized Mediterranean diet (MedDiet) administered to over 1200 elderly individuals aged 65–79 across five countries. Gender- and country-specific differences were observed in metabolite levels and body composition. Increased adherence to the NU-AGE MedDiet was associated with improved cognitive ability, episodic memory, reduced bone loss in osteoporosis, enhanced innate immune function, lower blood pressure, and improved arterial stiffness. In the current study, 612 participants from the NU-AGE trial had their gut microbial communities analyzed.
After the 12-month trial and data analysis, certain types of bacteria in the gut – influenced by diet – decreased as frailty increased. Moreover, those who improved their frailty status also showed a positive change in these bacteria. The control group had a slight increase in frailty compared to the intervention group, but it is important to note that a direct correlation between adhering to the diet and frailty wasn not observed. It is speculated that the effect of diet on frailty might be indirect through affecting the gut microbiome. To explore this, these researchers looked at how specific gut bacteria associated with diet were linked to frailty, cognitive function, and inflammation across all participants. They found that certain bacteria were consistently linked to different markers. Some were associated with increased inflammation and frailty, while others were associated with improved cognitive function and reduced frailty. Interestingly, these associations were consistent across different countries, suggesting that adherence to the NU-AGE Mediterranean diet was linked to a more beneficial gut microbiome composition, resulting in reduced frailty, better cognitive function, and lower inflammation.
In other words, the relationship between diet, gut bacteria, and overall health is complex and influenced by various factors. This study investigates one of the aspects contributing to the complexity of health, but factors like age, disease, and weight also play an important role. The beneficial nature of the Mediterranean diet is not something that is limited to the elderly. For example, similar improvements in health have been seen in obese individuals in previous studies. Despite the seemingly positive consequences shown in this study, the Mediterranean diet does have its limitations, including cost and impracticality in individuals with certain health conditions. Even so, identifying gut bacteria linked to health and aging offers the potential for developing targeted treatments to prevent frailty in older individuals.
– Yousuf Azizad