Diet and Consciousness: An Example

Introduction and Overview

Before writing this post in the form in which it appears here, I set out to write an entry on tyramine, an exogenously created nervous system stimulant which plays a major role, I believe, in the sorry state of modern consciousness. But as I wrote, the story I was trying to tell got longer and longer, and I found myself having to explain a lot of “backstory” just to make sense of it all. Soon I found myself with a much larger story than I had anticipated writing, but it turned out to be the very story which inspired me to create Neuromolecular in the first place.

It is a story of one of the ways in which something as simple as diet can shape the quality of our consciousness. The story begins with facts about nutritional chemistry and neurochemistry. To this, I will add a fair amount of my own speculations. I believe these speculations to be novel insights and not unreasonable or inconsistent with the facts I will be presenting. However, I make no claim to an authoritative knowledge on my subject; I am neither a trained nutritionist nor a research neuroscientist. My story is the result of armchair study of the various topics at hand and is offered as a hypothesis suggestive of actual clinical research.

The story begins not with tyramine but with tyrosine, an essential amino acid found in many foods–fruits, vegetables, grains, legumes and animal products included but most abundantly in the latter. Certain bacteria present in most foods containing tyrosine convert a certain amount of the amino acid to a derivative compound called tyramine. From there, from these two food-borne chemicals, I will trace out two parallel narratives and contrast their different effects on the mind.

Tyrosine, when ingested, is absorbed through the gastronintestinal tract, and a certain amount of it eventually finds its way through the blood-brain barrier to become the intigating chemical in a metabolic pathway that includes major neurotransmitters. Tyrosine is converted to l-DOPA, itself a precursor for dopamine, the so-called “reward” or “pleasure” neurotransmitter. Used dopamine is metabolized to form noradrenaline (also called norepinephrine), a neurotransmitter implicated in wakefullness and sustained concentration. Noradrenaline is in turn used to create adrenaline, a neurotransmitter important to both mental and physical activity. Tyrosine thus begins a neuromolecular chain of events which translates at the level of consciousness to motivation (“pleasure”) becoming concentration becoming action. In actuality, each neurochemical network involved triggers the next in such rapid succession that there is little differentiation in the mind of the one experiencing it between the separate phases.

But separate they are, and this is important for the consideration of the fate of tyramine. Though found in the same foods as tyrosine and in fact created from tyrosine, tyramine is a neurotoxic and mildly addicting stimulant. The body has fortunately developed defenses against the substance, and the vast majority of the tyramine found in the average American meal must be neutralized in the gut by a chemical called monoamine oxidase. In fact, if monoamine oxidase were not present in the body, the average American meal could prove fatal to most people. However, the presence of high amounts of both tyramine and monoamine oxidase in the body can have negative effects on mood. Tyramine is a stimulant, an agonist at both the noradrenaline and adrenaline receptor sites (while skipping over the dopaminergic “pleasure” sites). Monoamine oxidase (MAO) on the other hand is associated with both aggressive behavior and depression. MAOs find their way into the brain and are used to permanently break down dopamine and serotonin, the two neurotransmitters most thought to play a role in overall mood.

I will endeavor to explain in depth both these metabolic “trajectories” and their effect on individual consciousness as well as speculate on the state of contemporary American consciousness based on their diet. Along the way, I will advocate a largely vegetarian–if not exclusively vegan–diet, though with a few caviats. Most advocates of vegetarianism approach the subject from the standpoint of long-term overall health; I’ll be making the novel argument based on the immediate neurological benefit of such a diet.

The series, like everything on Neuromolecular, is a work in progress and will probably be subject to revision at a later date. I welcome all insights and criticisms.