Evidence of the association between the gut microbiome (the microorganisms living in the intestines, including bacteria, viruses, fungi, and protozoa) and the brain, keeps getting stronger. Several studies have shown that the diverse microbes in the gut heavily impact our overall health—but especially our brain. There’s a two-way line of communication between gut bacteria and brain cells. A new study suggests that that back-and-forth chatter has the ability to shape the brain’s white matter (the area of the brain that affects learning and brain function).
What we eat shapes the composition and abundance of our microbiome. Based on this notion, researchers manipulated the gut microbiota of male rats by regulating their diets. They found that diet-specific gut microbiota can influence the structure of white matter. That is, what you eat ends up changing your gut microbes and they end up shaping and organizing the brain’s white matter.
The team of researchers believes that gut microbes exert their influence through bacterial metabolites. In other words, short-chain fatty acids, produced by the bacterial fermentation of dietary carbohydrates, are responsible for changes in neuronal movement that shape white matter. By examining diet and how it affects the communications between gut microbiota and changes in the neural tissue microstructure, researchers were able to see that gut microbes also influence the central nervous system (CNS) via neural, endocrine and immunological highways.
Gut bacteria also manufacture a wide spectrum of neuroactive compounds such as dopamine, histamine, acetylcholine and tryptophan, (the precursor to serotonin). They also found a chemical receptor that responds to the changes induced by gut microbes to shape cerebral cavernous malformations. The study is published in the journal Translational Psychiatry.
According to another study from researchers at the University of Cork, gut microbes can also influence other parts of the brain. This study looked at the structure of the prefrontal cortex. Researchers found microbiota influences can shape the brain’s structure and how it functions by regulating myelination. Myelination protects nerve fibers by providing a type of insulation. It works like an electrical tape, protecting the nerve fibers and the electrical impulses they have. This allows the nerves to conduct themselves properly and communicate with cells. Changes in myelin could be reversed, say the researchers, by regulating gut microbe colonization. The study suggests regulating microbiota as a potential therapy for psychiatric disorders involving irregular myelination in the pre-frontal cortex.
There’s still more research to be done – particularly on how gut microbes influence the brain’s function and structural changes, as well as the central nervous system. But several studies have already found that the microbiome can influence mood, mental illness and depression.
According to a recent study an acute change in diet, for instance to one that is strictly animal-based or plant-based can change the microbial composition within 24 hours of initiation, and reverse within 48 hours of diet discontinuation. The right diet can keep a healthy balance of the gut microbiome population. But how should you alter your diet? Well, some studies show that the Mediterranean diet, (a diet characterized by a high consumption of vegetables, olive oil and moderate consumption of protein) can protect the white and grey matter of the brain while populating the gut with good bacteria. In my practice, I find that abstaining from gluten and animal dairy also helps keep the brain and gut balanced. Taking a good daily probiotic can also help support a healthy intestinal microecology.
In general, a diet that supplies a diversity in gut bacteria is best. In addition to eliminating gluten and dairy, some great choices to consider adding to your diet are cruciferous vegetables (like broccoli, cabbage, kale, and brussel sprouts). A study conducted in 2009 showed that cruciferous vegetable consumption alters the growth of certain bacteria, thereby altering the gut microbiome.
I also tell my patients to consume a variety of healthy foods, including grass-fed beef, pasture raised poultry, organic fruits and vegetables of varying colors, and good fats like avocados, olive oil and nuts. It’s important to enjoy a variety to ensure you are getting as many nutrients and minerals needed for optimal health. This will also support your microbiome and your brain health.