(P22-068-25) Prebiotics, Probiotics, and Synbiotics: What Are the Impacts on Neurotrophic Factors in the Elderly?

Objectives: This review examines clinical trials and before-and-after studies on the effects of prebiotics, probiotics, and synbiotics on neurotrophic factors (NTFs) in older adults. It explores the relationship between NTFs, gut microbiota, and aging aiming to assess how these supplements influence NTFs.

Methods: A literature search was conducted in May 2024 across PubMed, Web of Science, Scopus, and ProQuest using terms related to prebiotics, probiotics, synbiotics, and neurotrophic factors. Eligible studies included human randomized clinical trials (RCTs) or before-and-after studies published in peer-reviewed journals, focusing on NTFs in elderly populations. The selection process was independently reviewed by three researchers.

Results: NTFs like brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and glial cell line-derived neurotrophic factor (GDNF) are crucial in aging and cognitive function. Decreased NTF levels are linked to cognitive impairment, neuroinflammation, and reduced neuroplasticity. Some studies showed probiotics and synbiotics, particularly Bifidobacterium strains, can increase BDNF levels, while others found no significant effects. Prebiotics showed mixed results, with minor changes in gut microbiota but no major impact on NTFs. The review highlights microbial dysbiosis, which increases with aging, as a factor in neuroinflammation and cognitive decline, suggesting that changes in gut microbiota may influence NTF expression, particularly BDNF, via the gut-brain axis. Moreover, evidence on IGF-1 is limited. Some studies suggested probiotics may slow IGF-1 decline, while others found no effect. Prebiotics, especially those with calcium, vitamin D, and soy isoflavones, showed potential in increasing IGF-1, but more research is needed.

Conclusions: The effects of prebiotics, probiotics, and synbiotics on NTFs in older adults remain inconclusive, with mixed findings. There is some evidence for modulation of BDNF, but the impact on IGF-1 is unclear. Further long-term randomized trials are needed to better understand how prebiotics, probiotics, and synbiotics affect various NTFs, including BDNF, IGF-1, GDNF, and NGF to clarify the therapeutic potential of these interventions in aging-related diseases.

Funding Sources: This research received no external funding.