Protect Your Brain Like You Mean It. Role of the Microbiome and Short-Chain Fatty Acids on Blood-Brain Barrier Integrity

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Megan Pribyl, PT, CMPT is a physical therapist at the Olathe Medical Center in Olathe, KS treating a diverse outpatient population in orthopedics including pelvic rehabilitation. Megan’s longstanding passion for both nutritional sciences and manual therapy has culminated in the creation of her remote course, Nutrition Perspectives for the Pelvic Rehab Therapist, designed to propel understanding of human physiology as it relates to pelvic conditions, pain, healing, and therapeutic response. 

I have always viewed resultant health as the sum total of nutrition, exercise, lifestyle factors, environmental/toxicant & chemical exposure, genetics, and spiritual confluences. In balance, health and vitality flourish. Out of balance, health struggles manifest. If we take a look around, we bear witness to modern culture’s harmful effects upon our physiology – and specifically on our blood-brain barrier (BBB). Health struggles affecting the brain and impacted by BBB dysfunction are diverse and can include anxiety, depression, chronic pain, and neurodevelopmental disorders. Other disorders linked to a compromised BBB include Alzheimer’s disease, dementia, Parkinson’s Disease, and MS. So we ought to care a lot about our BBB – yet most of us don’t make conscious lifestyle choices based on protecting this vital gatekeeping system. Perhaps if we examine one specific angle of this issue -  that diet and short-chain fatty acids influence the integrity of the blood-brain barrier – we might decide to care a lot more about protecting our brain – like we mean it.

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For starters, it helps to acknowledge that our entire body IS an immune system – one that is constantly surveying potential threats to our existence. It is very well established that 70% of our immune system resides in our gut. This placement makes sense because the very act of eating exposes our inner workings to whatever “food” passes through the alimentary canal. Our digestive tract is a frontline sorting station that decides what can pass through the intestinal barrier and what cannot. Having a strong intestinal barrier is critical to maintain health as evidenced by a wealth of both animal and human studies.

Most of us also don’t constantly think about our intestinal barrier – but science contends that we should. Because what happens there impacts our entire body and all systems – including our nervous system. A recent study even describes a “Gut Spinal Cord Immune Axis” wherein the health of our spinal cord itself is dependent on immune factors regulated by the gut microbiota. (3) That’s how far your gut health influence goes.

So, let’s talk about one way our gut, a.k.a. microbiome, keeps us healthy. The microbes in our large intestine should be numerous and diverse. These microbes thrive in the presence of prebiotic fiber components (sources of prebiotic fiber are diverse, from the plant world and include things like Jerusalem artichoke, bananas, onions, berries, garlic, and other herbs and spices) which arrive in the colon because they are consumed by the host – us. When your microbes feast on the prebiotic fibers, they produce a by-product, and this byproduct is SCFA’s or short-chain fatty acids. It is well established that these SCFAs play a powerful immunomodulatory role both locally (in the intestine) and distantly (e.g. at the blood-brain barrier). This is the best way to create healthy short-chain fatty acids so they can do what they do best in our system – modulate inflammation.

But what happens if we don’t have richness (as in ample number) or diversity (as in different health-promoting species) of microbes in our large intestine? We can’t produce as many SCFAs.  

What happens if we don’t consume the food (eg. prebiotic fiber) our microbes like to eat? Or if we aren’t eating foods that contain microbes (eg. cultured foods)? We can’t produce as many SCFAs.

What happens if we are deficient in healthy SCFAs?  We may end up with undesirable physiological sequelae such as systemic inflammation. Which can include blood-brain barrier inflammation. (2)

Remember that we have nerves everywhere in our body – centrally and peripherally. If any of the nerves in our body (peripheral nerves), brain (CNS), or gut (ENS) are inflamed, this can be termed neuroinflammation. Neuroinflammation in the CNS  leads to blood-brain barrier inflammation resulting in increased permeability – this ultimately allows substances to reach the brain that shouldn’t. 

Neuroinflammation is at the root of many of the health sequelae we currently see in non-communicable conditions. (5) Maybe in your patient it manifests as chronic pain. Maybe in your friend, it’s anxiety and depression. Maybe in your aunt it’s MS, your uncle it’s Alzheimer’s. Maybe in your neighbor it’s fibromyalgia. Neuroinflammation has many faces.

When we look at factors that contribute to blood-brain barrier dysfunction, many can be traced to the cumulative effects of a standard American diet and lack of nutrient density. Further, and more ubiquitous – is our unseen exposure to toxicants such as herbicides and pesticides as well as a multitude of other potential cell health disruptors. (1, 4)

Because of the massive implications of human disease states, we need to pay attention to what the literature is telling us about the interconnected nature of health and lifestyle. We must stop polluting our human physiology and we must start feeding ourselves food that isn’t paradoxically decimating our microbiome. It’s that simple. And complicated. At the same time.

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Taking a deep breath is the first step. A crucial second step is staring down the truth of our country’s health care and agricultural realities. The third is gaining perspective on what actions each of us can take today – wherever we live, whatever our socioeconomic status, and whatever our current health status. There is much work to do.  

I invite you to an opportunity to learn about many actions we can take today and examine nutritional concerns in depth that have implications not only for the population you treat as a pelvic rehab therapist but for yourself, your friends, and your extended human family.  

We must prioritize protective health choices. We must care for our gut, propagate healthy short-chain fatty acids, and therefore care for our blood-brain barrier. And subsequently, protect our brain - like we mean it. Because our modern culture will not do that for us. Solving our nation’s health crises will take each of us collectively to make a difference. The health status of our nation can improve – one protected brain at a time.

Join us for our next offering of Nutrition Perspectives for the Pelvic Rehab Therapist scheduled for June 10-11, 2023.  


  1. Abou Diwan M, Lahimer M, Bach V, Gosselet F, Khorsi-Cauet H, Candela P. Impact of Pesticide Residues on the Gut-Microbiota-Blood-Brain Barrier Axis: A Narrative Review. Int J Mol Sci. 2023 Mar 24;24(7):6147. doi: 10.3390/ijms24076147. PMID: 37047120; PMCID: PMC10094680.
  2. Fock E, Parnova R. Mechanisms of Blood-Brain Barrier Protection by Microbiota-Derived Short-Chain Fatty Acids. Cells. 2023 Feb 18;12(4):657. doi: 10.3390/cells12040657. PMID: 36831324; PMCID: PMC9954192.
  3. Raue KD, David BT, Fessler RG. Spinal Cord-Gut-Immune Axis and its Implications Regarding Therapeutic Development for Spinal Cord Injury. J Neurotrauma. 2023 Mar 10. doi: 10.1089/neu.2022.0264. Epub ahead of print. PMID: 36509451. 
  4. Sharma T, Sirpu Natesh N, Pothuraju R, Batra SK, Rachagani S. Gut microbiota: a non-target victim of pesticide-induced toxicity. Gut Microbes. 2023 Jan-Dec;15(1):2187578. doi: 10.1080/19490976.2023.2187578. PMID: 36919486; PMCID: PMC10026936.
  5. Takata F, Nakagawa S, Matsumoto J, Dohgu S. Blood-Brain Barrier Dysfunction Amplifies the Development of Neuroinflammation: Understanding of Cellular Events in Brain Microvascular Endothelial Cells for Prevention and Treatment of BBB Dysfunction. Front Cell Neurosci. 2021 Sep 13;15:661838. doi: 10.3389/fncel.2021.661838. PMID: 34588955; PMCID: PMC8475767.

Nutrition Perspectives for the Pelvic Rehab Therapist

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Price: $525.00          Experience Level: Beginner          Contact Hours: 17.5 hours

Course Dates: June 10-11, September 16-17, and December 2-3

Description:  Participants will be introduced to the latest research in nutrition through immersive lectures and hands-on labs.  The course will cover essential digestion concepts, nourishment strategies, and the interconnected nature of physical and emotional health across the lifespan. Further, clinicians will delve into nutritional relevancies in bowel and bladder dysfunction, pelvic health, pain, and healing.  Labs throughout include insightful demonstrations and breakout sessions. The course participant will acquire new, readily applicable tools for patient empowerment, engagement, and self-management utilizing presented principles.

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