It’s Not Just in Your Head, It’s in Your Gut!
December 26, 2017 | 6 minute read | by Natasha Hawthorn
Have you ever wondered what that piece of food you just ate has to do with your brain function? Or maybe you know someone who has been to the Doctor with digestive symptoms, brain fog, fatigue, and so on, just to be told that the tests came back normal and it must all be in their head? Most people have heard the phrase “you are what you eat” and are aware of the fact that their muscle mass, energy levels, and digestion are dependent on their diet. The brain-gut connection has been getting increasingly more traction in the media over the last few years, but it still seems to be a fringe topic and the traditional medical profession is slow to respond.
The State Of Microbiome Research
As strange as it sounds to say this, researchers are just now beginning to understand how interconnected the human body is. For example, Emeran Mayer, a UCLA researcher who co-authored this study  in the journal Gastroenterology in 2013, was quoted in The Atlantic  saying “This was not what we expected, that eating a yogurt twice a day for a few weeks would do something to your brain.” The article went on to say “He thinks the bacteria in the yogurt changed the makeup of the subjects’ gut microbes, and that this led to the production of compounds that modified brain chemistry.”
Personally, I am baffled that in the 21st century scientists at major universities are surprised by the connection between what we eat, the microbiome, and the brain. As Robb Wolf writes in his book Wired To Eat , the modern food manufacturers have pulled a curtain over our eyes by offering easy access to an abundance of over-processed, hyper-palatable edible substances creating all manner of confusion about something as basic as food and what it does to our bodies. Modern medicine has us convinced that unless a peer-reviewed study (on a small sample size, mind you) has been published in a well-known journal, all anecdotal evidence, regardless of the number of “anecdotes” collected over hundreds or even thousands of years, is invalid until proven true by said study. But I digress.
Cartoons That Teach
When my kids were little they used to watch a show called Magic School Bus. In one of the episodes, this magic bus full of elementary school kids gets swallowed by a classmate and the kids learn about digestion in simple, yet accurate terms. The cartoon showed what happens to food when our teeth chew it into smaller bits, then how the stomach acid breaks the bits down further, and finally how the villi in the small intestine absorb the nutrients into the blood stream where they can get delivered to their destination, and how the large intestine absorbs the water.
Allow me to take you on a journey of how neurotransmitters are built and delivered to the brain from the raw materials of the food you eat. Go ahead, picture that Magic School bus!
The Journey From Gut To Brain
As a bite of food your pearly whites just chomped up travels through your GI tract, it gets broken down into smaller and smaller pieces until enzymes in the small intestine break it down into amino acids on the molecular level. Amino acids are required for synthesis of neurotransmitters, which are chemical messengers transmitting signals between nerve cells in the brain and throughout the rest of the body.
The blood-brain barrier is your body’s defense system designed to keep your precious brain protected from harmful substances and is therefore very selective in terms of what compounds are granted passage. Most molecules are too large to cross it. Amino acids however, are small enough. Once absorbed through the villi in your small intestine they are sent to the brain via the blood stream for neurotransmitter synthesis. Key neurotransmitters are:
- Serotonin - the “happy molecule”
- Dopamine - the “motivation molecule”
- Acetylcholine - the “memory and learning molecule”
- GABA - gamma aminobutyric acid, the “relaxation molecule” 
The raw building blocks for these neurotransmitters include amino acids L-Tyrosine and L-Tryptophan, and a variety of other co-factors such as vitamins, minerals, and co-enzymes .
So, if you eat enough protein which will break down into amino acids, and some veggies for vitamins you should be all set, right? The twist is that the food you eat is not the only variable when it comes to availability of these nutrients for your brain. On top of what is already a highly complex process, the integrity of your small intestine wall will influence nutrient absorption, and therefore overall well-being.
When you consume inflammatory foods, such as refined carbohydrates, lectins found in grains, or oxidized vegetable oils, their metabolites can cause damage and leak through the small intestine into the blood stream if the tight junctions between the villi are compromised. The result can be felt as brain fog, fatigue, poor memory, pain, systemic inflammation and more. The health of your entire GI tract affects digestion of consumed protein and absorption of micronutrients, and the health of your endocrine system affects communication about delivery of these nutrients to the right destination. But there is one more key player.
Enter microbial residents of your intestines.
It’s Not a Bug, It’s a Feature…Unless It’s a Bug
Gut microbiome is an umbrella term that encompasses the vast diversity of the organisms residing in the human gastrointestinal tract - stomach, small intestine, and large intestine. Everyone’s microbial blueprint is unique, just like a fingerprint. The collection of beneficial and harmful bacteria and other microorganisms comprises a world of its own, evolving over time.
Bacteria are involved in metabolism of food we consume and synthesis of neuroactive molecules such as catecholamines, GABA, serotonin, and acetylcholine. More than 90% of the body's serotonin, as well as about 50% of the body's dopamine, lies in the gut. Dual function of these neurotransmitters is an active part of gut-brain research . Some microbes in the gut are also capable of releasing molecules that can directly activate the vagus nerve which talks to the brain about the state of the intestines . Certain strains of probiotics can increase the availability of tryptophan, key precursor to serotonin, bringing this back to the food you consume.
While the neurotransmitters can circulate through the blood and get delivered to the brain, the neuron cells in the brain have mechanisms to synthesize these important molecules on the spot. And that requires raw building blocks to be available at the right time in the right place.
The Connection – Bringing It All Home
To tie it all together: your mood after a meal is not an accident. Paying attention to your energy levels, and brain function can help you tune your diet to maximize the efficiency of the food you eat.
As Functional Diagnostic Nutrition practitioners, Chad and I at Anabolic Aces work with our clients to create a custom comprehensive diet and lifestyle protocol to heal or preserve gut integrity, boost or restore immunity, optimize brain performance, improve sleep, support detoxification, and provide resources and education for a sustainable healthy lifestyle. Because, you see, the human body *is* very much interconnected. Our thoughts and emotions may originate in the brain but not without a close connection to the gut. Humans co-evolved with an enormous variety of intestinal microbial species and literally can’t live without them. Restoring balance, correcting overgrowth, increasing diversity are all part of the process needed to optimize digestive processes in order to improve brain performance
So next time someone tells you your labs are fine and it must all be in your head, I suggest you seek a second opinion because it’s not just in your head.
 Wikipedia Gut-Brain-Axis
 Be Brain Fit - Neurotransmitter Balance
 Amino Acid Therapy - How Neurotransmitters are Made
 The Atlantic - When Gut Bacteria Change Brain Function
 Consumption of Fermented Milk Product With Probiotic Modulates Brain Activity, KIRSTEN TILLISCH et. al.
 Wired To Eat by Robb Wolf