A large-scale analysis of dietary metabolites, gut microbiota, dietary components, and endogenous metabolism in 842 people over age 65 identified a number of key plant-based foods most beneficial for preventing cognitive impairment in elderly people.
 
The new 12-year study, led by researchers at the University of Barcelona and the CIBER on Frailty and Healthy Aging (CIBERFES), relied on a collection of plasma samples, and linked metabolites derived from cocoa, coffee, mushrooms, red wine, and the microbial metabolism of polyphenol rich foods (apple, cocoa, green tea, blueberries, orange, and pomegranate) to the strongest protective association with cognitive impairment in the elderly.
 
While most studies are observational in nature, the present study relied directly on metabolic markers in a large-scale population in order to further substantiate conclusions reached about a number of dietary factors thought to influence cognitive outcomes. “Indeed, many dietary components can modulate the molecular mechanisms that are thought to contribute to cognitive decline, including oxidative stress, neuroinflammation, and vascular dysfunction […] however, most of this available evidence is observational and, often, inconsistent and fragmented. Part of these inconsistencies may be due to misreporting errors inherent to the food intake surveys that are commonly employed for dietary assessment, whereas biomarker-based studies, which are less prone to measurement errors, have been usually limited to only a few candidate biomarkers.”
 
“What we analyzed in the cohorts under study is the modulating role of the diet in the risk of suffering cognitive impairment,” Mireia Urpí-Sardà, from the department of nutrition, food science, and gastronomy at CIBERFES, said. “The results show a significant association between these processes and certain metabolites.”
 
Certain metabolites, such as 2-furoylglycine and 3-methylanthine, biomarkers of coffee and cocoa consumption, for example, had a protective profile, while saccharin, derived from the consumption of artificial sweeteners, was associated with a damaging role.
 
“The study of the relationship between cognitive impairment, the metabolism of the microbiota and food, and endogenous metabolism is essential to develop preventive and therapeutic strategies that help to take care of our cognitive health,” Mercè Pallàs, professor at the faculty of Pharmacy and Food Sciences at University of Barcelona, said.
 
Based on an overall analysis of the relationship between metabolic markers and neurodegenerative disease progression seen in the 842 participants of the study, which was part of a joint programming initiative “A Healthy Diet for a Healthy Life,” a higher intake of fruits, vegetables, and plant-based foods can provide polyphenols and other bioactive compounds that could reduce age-related cognitive decline, and should be emphasized in dietary recommendations made to older people who are more at risk.
 
The authors concluded that the study emphasized the importance of moving beyond single metabolites, and establishing optimal profiles of multiple metabolites and metabolic pathways, will provide more comprehensive results.
 
“We found evidence for disturbances in central metabolic pathways, such as the microbiota-modulated metabolism of aromatic amino acids, beta-oxidation, and others. Finally, our study highlights the great impact of inter-individual variation on metabolomics and, consequently, on the adequate performance of external validation studies,” the authors concluded. “This reinforces not only the added value of validating global biological/metabolic pathways rather than single metabolites, but also stresses the need for moving beyond biomarkers towards mechanisms and pathways in metabolomics research.”