Nutritional strategies modulating the gut microbiome as a preventative and therapeutic approach in normal and pathological age-related cognitive decline: a systematic review of preclinical and clinical findings

ABSTRACT

Context

The proportion of the elderly population is on the rise across the globe, and with it the prevalence of age-related neurodegenerative diseases. The gut microbiota, whose composition is highly regulated by dietary intake, has emerged as an exciting research field in neurology due to its pivotal role in modulating brain functions via the gut-brain axis.

Objectives

We aimed at conducting a systematic review of preclinical and clinical studies investigating the effects of dietary interventions on cognitive ageing in conjunction with changes in gut microbiota composition and functionality.

Methods

PubMed and Scopus were searched using terms related to ageing, cognition, gut microbiota and dietary interventions. Studies were screened, selected based on previously determined inclusion and exclusion criteria, and evaluated for methodological quality using recommended risk of bias assessment tools.

Results

A total of 32 studies (18 preclinical and 14 clinical) were selected for inclusion. We found that most of the animal studies showed significant positive intervention effects on cognitive behavior, while outcomes on cognition, microbiome features, and health parameters in humans were less pronounced. The effectiveness of dietary interventions depended markedly on the age, gender, degree of cognitive decline and baseline microbiome composition of participants.

Conclusion

To harness the full potential of microbiome-inspired nutrition for cognitive health, one of the main challenges remains to better understand the interplay between host, his microbiome, dietary exposures, whilst also taking into account environmental influences. Future research should aim toward making use of host-specific microbiome data to guide the development of personalized therapies.

KEYWORDS:

• Ageing
• cognitive decline
• gut microbiota
• nutritional strategies
• gut-brain axis
• mild cognitive impairment
• Alzheimer
• dementia

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Additional information

Funding

The authors reported that there is no funding associated with the work featured in this article.

Notes on contributors

Rieke Sproten

Rieke Sproten received a Bachelor of Science degree in Nutrition and Food Sciences from University of Bonn, Germany in 2017 and a Master of Science degree in Food Systems from University of Hohenheim, Germany in 2022. She has previously worked as a Science Communicator and Project Manager at the European Food Information Council. Her research interest centers on the neurobiological interplay between the gut microbiome and cognitive deficits, investigating diet's influence on this relationship.

Donatus Nohr

Donatus Nohr received a diploma in Biology in 1982 and his PhD (Dr. phil. nat.) in Zoology in 1985 from Goethe University Frankfurt, Germany. He received his “Habilitation” (equals assistant professor) in 1996 and his title apl. Professor in 2007 from University of Tübingen, Germany. From 2020 to 2022 (retirement) he was Head of the Department of Nutrition Science, University of Hohenheim, Stuttgart, Germany. His research interests include neuroscience, nutrition and micronutrients.

Daria Guseva

Daria Guseva received a diploma in Zoology in 2002 from Kazan State University, Kazan, Russia, and her PhD in Biology (Embryology, Cytology and Histology) in 2005 from Peoples' Friendship University of Russia (RUDN University), Moscow, Russia. In 2018 she received her “Doctor of Science” in Biochemistry and Molecular Biology from Federal Medical University Kazan, Kazan, Russia, and her “Habilitation” (equals assistant professor) in Neurophysiology in 2019 at Hannover Medical School, Hannover, Germany. From 2006 to 2009 she had her Postdoctoral Fellowship at the Center of Molecular Neurobiology, Hamburg, Germany. From 2009 to 2019 she was a Project- and Group Leader at the Department of Cellular Neurophysiology at Center of Physiology, Medical School Hannover, Hannover, Germany. From 2019 to 2022 she was a Project- and Group Leader at the Department of Nutritional Medicine, University of Hohenheim, Stuttgart, Germany. Since 2022 she is a Head of the Research Laboratory at the Institute of Child Nutrition, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany. Her research interests focus on the mechanisms of the communication between nutrition and gut microbiota, and its potential role in modulating neuronal plasticity and the onset of neurological disorders.