As food is an active subject and may have anti-inflammatory or pro-inflammatory effects, dietary habits may modulate the low-grade neuroinflammation associated with chronic neurodegenerative diseases. Food is living matter different from us, but made of our own nature. Therefore, it is at the same time foreign to us (non-self), if not yet digested, and like us (self), after its complete digestion. To avoid the efflux of undigested food from the lumen, the intestinal barrier must remain intact. What and how much we eat shape the composition of gut microbiota. Gut dysbiosis, as a consequence of Western diets, leads to intestinal inflammation and a leaky intestinal barrier. The efflux of undigested food, microbes, endotoxins, as well as immune-competent cells and molecules, causes chronic systemic inflammation. Opening of the blood-brain barrier may trigger microglia and astrocytes and set up neuroinflammation. We suggest that what determines the organ specificity of the autoimmune-inflammatory process may depend on food antigens resembling proteins of the organ being attacked. This applies to the brain and neuroinflammatory diseases, as to other organs and other diseases, including cancer. Understanding the cooperation between microbiota and undigested food in inflammatory diseases may clarify organ specificity, allow the setting up of adequate experimental models of disease and develop targeted dietary interventions.
Keywords: Alzheimer’s disease; Parkinson’s disease; amyotrophic lateral sclerosis; autism spectrum disorders; blood-brain barrier; diet; gut microbiota; inflammation; intestinal barrier; multiple sclerosis.
Conflict of interest statement
The authors declare no conflicts of interest
Unhealthy gut, unhealthy brain: The role of the intestinal microbiota in neurodegenerative diseases.Neurochem Int. 2018 Nov;120:149-163. doi: 10.1016/j.neuint.2018.08.005. Epub 2018 Aug 14. Neurochem Int. 2018. PMID: 30114473 Review.
Diet, Gut Microbiota, and Vitamins D + A in Multiple Sclerosis.Neurotherapeutics. 2018 Jan;15(1):75-91. doi: 10.1007/s13311-017-0581-4. Neurotherapeutics. 2018. PMID: 29067566 Free PMC article. Review.
The progress of gut microbiome research related to brain disorders.J Neuroinflammation. 2020 Jan 17;17(1):25. doi: 10.1186/s12974-020-1705-z. J Neuroinflammation. 2020. PMID: 31952509 Free PMC article. Review.
The Link between Gut Dysbiosis and Neuroinflammation in Parkinson's Disease.Neuroscience. 2020 Apr 15;432:160-173. doi: 10.1016/j.neuroscience.2020.02.030. Epub 2020 Feb 27. Neuroscience. 2020. PMID: 32112917 Review.
Brain-Gut-Microbiota Axis in Alzheimer's Disease.J Neurogastroenterol Motil. 2019 Jan 31;25(1):48-60. doi: 10.5056/jnm18087. J Neurogastroenterol Motil. 2019. PMID: 30646475 Free PMC article. Review.