Your Gut Bacteria Controls Your Brain

and Why APOE4 Carriers Stand Apart

Author

Dr. Kevin Tran
September 18, 2025

Phoenix friends,

Five researchers just presented game-changing findings about our gut bacteria...

I've been analyzing this multi-speaker conference session on diet and brain health, and what they discovered specifically about us is both sobering and hopeful.

Dr. Fernando from Australia studied our gut bacteria at the PRECLINICAL stage (before symptoms) and found: "APOE4 carriers have different bacteria and different representation of organisms."

We have FEWER beneficial bacteria like Lactobacillus and Bifidobacteria. The study didn't differentiate between those with one or two copies, but the pattern is clear.

BUT HERE'S THE HOPE:

Hui Chen's 10-year study proved the MIND diet slows brain shrinkage by 20%. That's 2-3 years of preserved cognition. And Dr. Ngouongo showed that Life's Essential 8 (especially diet, blood sugar, avoiding nicotine) directly increases protective bacteria.

The key insight from Dr. Fernando: Middle-aged adults (45-65) have the HIGHEST levels of protective Oscillibacter bacteria. This is our optimal window.

Dr. Denier-Fields connected it all: Diet-driven metabolites explain 20-29% of Alzheimer's biomarker variance. What we eat literally changes our brain pathology markers.

KEY FINDINGS

  • APOE4 carriers have fewer beneficial bacteria (study didn't differentiate hetero/homo)

  • MIND diet adherence = 20% slower gray matter decline over 10 years

  • Middle-aged adults (45-65) have highest levels of protective Oscillibacter

  • Diet metabolites explain 20% of p-tau217 variance

TAKE ACTION

Full analysis:

Credits

All credits to the AAIC 2025 (Alzheimer's Association International Conference) and its researchers.

Session Chairs:

Jennifer J. Manly (Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, NY, USA)

Hui Chen (Zhejiang University School of Medicine, Zhejiang, China)**Session

Presenters: 

Yannick Joel Wadop Ngouongo (Glenn Biggs Institute for Neurodegenerative Diseases, University of Texas Health Science Center at San Antonio, TX, USA) - Gut Microbiome Diversity as a Mediator Between Life's Essential 8 Adherence and Cognitive Function

Hui Chen (Zhejiang University School of Medicine, Zhejiang, China) - Adherence to the MIND diet and longitudinal brain structural changes over a decade: evidence from the Framingham Offspring cohort

Ameya Patwardhan (Lawson Research Institute; Parkwood Institute, ON, Canada) - bioMIND-A Novel Approach to Integrating Biomarkers in the Diagnostic Workup for Alzheimer’s Disease

Warnakulasuriya M.A.D.B. Fernando (Edith Cowan University, Western Australia, Australia; Australian Alzheimer's Research Foundation, Western Australia, Australia) - The Gut-Brain Connection: How Age, Sex, and APOE ε4 Influence Probiotic Balance in Early Alzheimer’s Disease

Diandra N. Denier-Fields (University of Wisconsin-Madison, WI, USA) - Diet-Driven Metabolite Patterns Link the MIND Diet to Dementia Biomarkers

Deepika Dinesh (Department of Public Health, University of Massachusetts Lowell, MA, USA) - Variations in the Gut Bacteriome and Virome Associated with Cognitive Function in Puerto Rican Adults