One of the questions I get asked the most by my readers is “what prebiotic and/or probiotic is the best?” Unfortunately, there is no good answer to that because we just don’t have the research to know. To boot, everyone’s body is different. Still, to help you all out as best as I can, I just finished reading a year-old paper on what we know about using prebiotics to treat anxiety, depression and cognitive issues.[i] You’ll never believe it (ha!) but there are not even vaguely enough clinical trials to know how to optimize their use. That said, there are some really interesting highlights in the paper and we can certainly conclude that prebiotics do play a potential role in helping alleviate symptoms.
The paper starts with emphasizing the fact that the main factor in determining the quality and quantity of microbiota is diet. And we know that the microbiota is a fundamental regulator of both intestinal and brain health, and the immune system. We also know that inflammation is one of the critical processes underlying several neurodegenerative and neuropsychiatric disorders including major depressive disorder (MDD), Alzheimer’s Disease (AD), Parkinson’s Disease (PD) and many others. Thus, the authors state, “…nutritional elements such as probiotics and prebiotics, could improve the host health due to their immunoregulatory properties.”
Probiotics and prebiotics that influence the brain are called psychobiotics. I first wrote about that new term way back in 2016 – see here. These can have anxiolytic (anti-anxiety) and anti-depressive effects, as well as altering cognition and emotions. This particular article reviewed what we currently have in terms of research on the effects of prebiotics, which, the authors state, “…may be useful as a potential therapeutic tool for cognitive impairment, anxiety and depression.”
A quick review: prebiotics refer to both digestible and non-digestible fibers that feed the microbiota. Many foods are rich sources including onions, garlic, bananas, asparagus, and more. Simply through eating a wide variety of fruits and vegetables, you are consuming a nice array of different prebiotics. We know that by promoting the growth of beneficial bacteria, prebiotics help with the maintenance of the intestinal barrier and reduce circulating levels of inflammatory markers (including IL-6, TNF and c-reactive protein). They can directly prevent the invasion of pathogens by “…decreasing endothelial adhesion due to their anti-adhesive property.” I thought that was particularly interesting in light of that research I posted earlier this week, on a fungus that adheres to the inflamed and damaged tissue seen in Crohn’s disease, preventing wound healing. Finally, prebiotics promote the grown of bacteria that produce stress neuromodulators as well as short-chain fatty acids, about which you have read a lot on this blog. So, all in all, the right prebiotics have tremendous beneficial potential.
There are too many studies reviewed in the paper for me to go into them all so I’ll just give you a small sampling:
Unfortunately, clinical studies are “scarce.” Most, as you can see, are done on animals because of the overwhelming expense of human trials. Still, I hope this post gives at least some guidance and/or ideas to those of you who would like to add prebiotics to your daily regime.
[i] Paiva IHR, Duarte-Silva E, Peixoto CA. The role of prebiotics in cognition, anxiety, and depression. Eur Neuropsychopharmacol. 2020 May;34:1-18. doi: 10.1016/j.euroneuro.2020.03.006. Epub 2020 Mar 30. PMID: 32241688.