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How the Gut Impacts Brain Inflammation

Updated: Mar 11

And what to do about it today!

By Austin Perlmutter, MD



In the last decades, scientific research has shown us that what happens in the gut impacts the brain. We’re now learning that mental health issues to and cognitive issues like Alzheimer’s as well as brain autoimmune issues relate to the makeup of our gut microbiome, our gut immune system, and our gut immune cells. One of the most important pathways linking gut problems with brain issues relates to inflammation.

What is inflammation and why does it matter?


Inflammation is an incredibly helpful state of immune activation in certain cases. However, when inflammation goes on at low levels for long periods of time, it dramatically enhances our risk for developing a number of health issues. We’ve also learned just in the last few years that inflammation in our bodies may relate to inflammation in our brains, and inflammation in our brains is of the most important risk factors for a wide spectrum of mental and cognitive issues. So how does the gut impact inflammation in our bodies and brains?


How the gut is linked to inflammation

Our GI tract (or gut) must maintain a very delicate balance between absorbing the things we need (aka, food nutrients) and keeping out things that can damage our health (e.g., certain bacteria). This complex dance must occur across the entire 26 or so feet of the gut. Certain environmental influences may increase the chances that our gut lets in harmful molecules, and when this happens, we may increase inflammation in our bodies. For example, stress, a highly processed diet, excess alcohol, antibiotics, infections, and more are linked to damage to the gut lining.


When our gut gets “leakier,” toxins from the gut microbiome can activate our immune cells and create inflammation in our bodies. This inflammation may damage the brain’s protective barrier (the blood brain barrier), which allows inflammation from the bloodstream to enter then brain. In addition, pieces of gut bacteria that enter the bloodstream may be able to damage the blood brain barrier directly. Lastly, inflammation in the gut, as well as toxins from gut microbes may be able to activate the vagus nerve, although this may have an anti-inflammatory effect in the brain.


All this research is more reason to prioritize gut health as a way to prioritize better brain health. So, what can you do today to help prioritize better gut health?


  1. Eat a Diverse Range of Foods: Eating more diverse plant foods is linked to an enhanced diversity of your gut microbiota. Different types of bacteria thrive on different nutrients; by eating a wide range of foods, particularly fruits, vegetables, legumes, and whole grains, you help support a diverse microbial environment. Also, by eating more real plant-based foods, you limit exposure to highly-processed junk foods that are linked to worse gut health and higher inflammation.

  2. Consume Plenty of Fiber: High-fiber foods like legumes, beans, peas, oats, Jerusalem artichoke (sunchokes) bananas, berries, asparagus, and leeks can promote the growth of healthy bacteria and help with digestion. Fiber cannot be digested by your body, but it can be digested by certain potentially health-promoting bacteria in your gut, which stimulates their growth, and may help to protect the gut lining.

  3. Incorporate Fermented Foods into Your Diet: Fermented foods such as yogurt, sauerkraut, kefir, kimchi, and kombucha are rich in lactobacilli, a type of bacteria beneficial for your gut. Be careful though, some of these foods are still packed with added sugar that’s likely to negate the benefits of the fermentation!

  4. Limit Artificial Sweeteners: Some largely preclinical studies suggest that artificial sweeteners like aspartame can stimulate the growth of unhealthy bacteria in the gut microbiota. Avoiding these may help maintain a healthy gut flora.

  5. Prioritize Polyphenols: Recent research suggests that plant compounds called polyphenols may have a particularly important effect on maintaining healthy gut microbiome balance, as well as balancing the gut and systemic immune system to keep inflammation in check. Some great sources of polyphenols are colorful fruits and vegetables, spices, and herbs as well as coffee and tea.

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