Gut-Brain Relationship

How your gut and brain are connected?

Though your gut and brain are housed in different parts of your body, they are physically connected via the Vagus nerve originates in the brain stem and travels along to the gut, connecting the gut to the central nervous system. When it reaches the gut, it entangles itself to form little threads that wrap the entire gut.

Because the Vagus nerve penetrates the gut wall, it plays an essential role in the digestion of food but its key function is to ensure that nerve signals can travel back and forth between the gut and the brain. Signals between the gut and brain travel in both directions, making the brain and gut lifelong partners.

Before your gut and brain became distinct entities, they were one. They came from the same fertile egg that gave rise to all organs in your body. In fact, the central nervous system, made up of the brain and spinal cord, is formed by special cells known as neural crest cells. These cells migrate extensively throughout the developing embryo, forming the enteric nervous system in the gut. The enteric nervous system contains between 100 million and 500 million neurons, the largest collection of nerve cells in the body. That's why some people call the gut "the second brain".  It's also why the gut and brain influence each other so profoundly.

Role of Microbiome

Behind the gut-brain relationship is a huge collection of microorganisms that live in the gut so called "Microbiome". Your gut has about 39 trillion microorganisms in it. Collectively it weighs about three pounds, which is the same way as your brain. Our guts provide the bacteria with a place to live and thrive, and in return they perform crucial tasks for us that our bodies cannot perform on their own. We feed these organisms and they produce chemicals that we need.

When it comes to bacteria, there are good guys and bad guys. The microorganisms that live in the gut are normally good guys, but it's inevitable that some bad ones get mixed in. This is not necessarily a concern as your body generally make sure the good and bad bacteria stay at the right balance. But if diet, stress, or medication cause changes in gut bacteria, it can cause a ripple effect that leads to many negative health effects including mental function.

Scientists know that people who are depressed and anxious have very different microbiomes than people who are not depressed. With depression you have a higher number of bad bacteria that produce inflammatory chemicals, they send these inflammatory chemicals back to the brain and they get distributed in the body. Different collections of bacteria affect brain chemistry differently. For example, changes in proportions and function of Escherichia, Bacillus, Lactococcus, Lactobacillus and Streptococcus can result in changes in Dopamine levels and may predispose one to Parkinson's disease and Alzheimer's disease.

In addition to regulating neurotransmitter levels, there are various other ways in which microbiota influence the gut brain connection. They are involved in the production of other important compounds like BDNF (brain derived neurotrophic factor) which supports the survival of existing neurons and promotes new neuron growth and connections. They influence the integrity of the gut wall which protects the brain and the rest of the body from substances that need to be confined in the gut.

How to take care of your good gut bacteria?

The ideal scenario is to have a diverse population of bacteria strains. Similar to fertile top soil needing diverse microorganisms, our microbiome values diversity! There are many factors that influence your gut bacteria diversity.

1. Diet

Clean up your diet by eliminating or reducing processed foods, sugar and red meat. Diets high in processed foods, sugar, red meat and fast food promote the bad bacteria.

Eat safe prebiotics. Prebiotics are the fiber that feeds the bacteria and keeps them in circulation. These are foods that are high in inulin, polyphenols and polyunsaturated fatty acids. Some examples of prebiotics are onion, garlic, bananas, walnuts, oily fish, and oats. Check out our article 'Eat for your Microbiome'

Eat probiotics. Probiotics contain the actual bacteria that you ingest to increase the good population of bacteria. You can get them from your diet, or supplements. It's always best to get important nutrients from your food rather than supplements because these foods contain live bacteria. Some examples of dietary probiotics are yogurt, sauerkraut, kimchi, pickles and kombucha.

You can increase the diversity by taking probiotic supplements along with eating probiotic food. The probiotic capsules contain freeze dried bacteria, that reconstitute once they get past the stomach and into the gut.

It matters when you take your probiotic supplements - you need to take them on an empty stomach before for your meal because your stomach secretes acid as part of the digestive process to break down your food. The most common good bacteria strains can survive the stomach acid if they're not exposed to the acid for too long. If you eat them with a heavy meal, there's a long waiting line as the food gets processed so the bacteria can get killed off while they sit in the stomach.

2. Sleep

Bacteria are sensitive to circadian rhythm changes, so poor sleep promotes bad bacteria and increases inflammation. Set a consistent bedtime that allows you to get seven to nine hours of sleep each night. Even if you've never been depressed or anxious, good gut health begets good overall health including maintaining a proper weight.

3. Stress

As mentioned earlier, the gut-brain connection works both ways. So if gut bacteria can influence the brain, it is also true that the brain can change gut bacteria. All it takes is 2 hours worth of psychological stress to completely change bacteria in your gut.

For example, Lactobacillus normally help break down sugars into lactic acid, prevent harmful bacteria from lining the intestine and protect your body against fungal infections. But when you are stressed, stress disrupts its functioning, leaving you expose to harm.

When you have depression or anxiety, all these normal protective effects on the gut are compromised. As a result, food is not properly absorbed resulting in negative effects on the rest of the body.

4. Aerobic Activity

Aerobic activity improves the diversity of your microbiome. This could be 30 minutes of brisk walking or swimming five days a week.

Medications/Antibiotics

Lots of Medications and not just antibiotics can change the population of your gut in a negative way.