Gut Microbiome Link to the Gut Microbiome heading

Microbiome means "the microorganisms living in a particular environment" so a gut microbiome refers to all the microorganisms living in the gut. Sometimes referred to as gut microflora, or gut microbiota, the first mention of this topic in western literature was in 1840. Since 1840, the recognized role of bacteria in our digestive tract has grown, encompassing broader implications for health, disease prevention, and even mental and emotional health.

Gut bacteria and our brains Link to the Gut bacteria and our brains heading

There is ongoing research in this topic. The main question is: "how?" and the answer is, we aren't sure. To summarize, many chemicals that we know affect our brains such as serotonin and dopamine are created in our guts as well as in our brains. When these chemicals are created in our gut it was typically thought that they are unable to cross the blood-brain barrier. This lead the initial hypothesis to be that gut created neurotransmitters did not affect our brain the same way that the same neurotransmitter does when it is created in the brain, which lead to a broader sense that gut bacteria did not have a direct relationship with our brain.

However some research has come out that shows that there might be a more direct relationship between gut and brain. Some note worthy studies have found for example that women who consume yogurt twice a day reacted significantly calmer during stressful situations than women who did not consume yogurt. Another, pretty mind blowing, study found that 4 specific bacteria were associated directly with mental quality of life, as well as even more mind blowingly, people whos gut microbiome created more dopamine metabolites had higher mental quality of life. 

The question remains: "how?", so let's go over some potential mechanisms:

• First the Vagus Nerve is a critical pathway for the bidirectional communication between the gut and the brain. Some microbiota can affect brain chemistry via the vagus nerve, impacting behaviors, mood, thoughts, and other cognitive abilities​.
• Second is inflammation, dysfunctions or imbalances in the gut microbiome (dysbiosis) can lead to an overproduction of inflammatory cytokines, which have been linked to depression. Conversely, a healthy gut microbiome can contribute to a more balanced immune response and potentially lower inflammation, thereby influencing mental health​.
• Third is it might be possible that having more serotonin and dopamine created in your gut might actually be able to affect your brain in a way we don't know, because we have seen evidence that having these chemicals in your gut will affect your mind in the ways the brain version of the chemicals do. 

Anyways honestly, the how is very technical and not fully understood even by scientists. The important studies are referenced at the end of this page, and for now we can just assume that good gut bacteria is good and bad gut bacteria is bad. The question now becomes, how do I get good bacteria and reduce bad bacteria? 

Diet and gut bacteria Link to the Diet and gut bacteria heading

Probably everyone has heard of probiotics and most have heard of prebiotics by now, but this concept seems a bit odd and under developed to me. Do I really need to just keep a steady flow of yogurt in order to be smarter? What even is a probiotic? What is a prebiotic? How do I know I'm not just feeding the bad bacteria by consuming this bacteria food? 

Probiotics Link to the Probiotics heading

Probiotics are live microorganisms that offer health benefits when consumed in adequate amounts, according to the World Gastroenterology Organization. Here's some more information for International Scientific Association for Probiotics and Prebiotics (ISAPP). Some common probiotics like Lactobacillus, Bifidobacterium, Saccharomyces boulardii, Streptococcus thermophilus, and Enterococcus faecium have been studied the most, but there are surely probiotics we that remain undiscovered.

Some naturally occurring probiotics include, yogurt and some cheeses, kefir, kombucha and home made kimchi and sauerkraut (not shelf stable canned versions). 

Prebiotics Link to the Prebiotics heading

Prebiotics are food sources that the "good guys" use and the "bad guys" do not. Prebiotics are determined based on their ability to be selectively utilized by beneficial gut bacteria to promote health. Prebiotics are primarily plant-based fibers. They are carbohydrates that humans cannot digest, which beneficial gut bacteria ferment. These are mostly soluble fibers, found in fruits, vegetables, and grains. Here's some more information from ISAPP 

Galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS), oligofructose (OF), chicory fiber, and inulin are prebiotics that primarily feed beneficial bacteria like Bifidobacteria and Lactobacilli. Each prebiotic type can slightly vary in which specific strains of bacteria they most effectively promote, but overall, they contribute to a healthy, balanced gut microbiome.

Resources Link to the Resources heading