"Your brain...weighs three pounds and has one hundred thousand miles of blood vessels, contains more connections than there are stars in the Milky Way, is the fattest organ in your body, could be suffering this very minute without your having a clue." Dr. David Perlmutter, Grain Brain.
Leaky gut. Have you heard this term before? If you are in the conventional medical world, maybe you have heard the term "intestinal permeability." Leaky gut is a buzz term right now and for good reason! There are also a lot of misconceptions about leaky gut floating around on the internet. Simply put, leaky gut is a condition in which the lining of the gastrointestinal tract, specifically the small intestine, is damaged, or "leaking" substances (some toxic and some nontoxic) into the body. Let me get into the basic science of leaky gut.
Disclaimer: This is an over simplified explanation of leaky gut. If you are interested in more in depth information, I can provide that for you, or point you in the right direction.
The small intestine is made up of cells, which lie "shoulder to shoulder" with a very narrow opening (junction) between each cell. These junctions only allow small particles, such as nutrients (vitamins, minerals, etc.), to pass through into our blood stream to be transported throughout the rest of the body. These same junctions also prevent larger molecules (pathogens, bacteria, food proteins) from passing into the blood stream. Think of the small intestine like a net. If you stretch out the net, the holes expand, allowing larger objects to pass through. Our gut could be thought of as a wall to protect a city, preventing foreign invaders from intruding. Within our blood stream, we have circulating white blood cells (immune cells) that are patrolling, ready to attack foreign invaders. If an invader gets past the protective wall then the soldiers (immune cells) attack. It is a highly intelligent system that keeps us healthy. This system, when damaged, wreaks havoc on the body, leading to a myriad of problems. So how does this system get damaged, and therefore cause problems? Let me explain.
The small intestine cells can be damaged over time by several offenders including, but not limited to: antibiotics, steroids, stress, heavy metals, bacteria, NSAIDs, and the Standard American Diet (SAD.) These substances gradually breakdown these tight junctions, creating large "holes" in the small intestinal cells, thus allowing large particles (pathogens, whole-food proteins) to leak through. When these particles leak through into the bloodstream, the immune cells are activated and release chemicals called "mediators." These mediators initiate the inflammatory response in the body, which can range from a headache, bloating, joint pain, cloudy brain, allergies, among a laundry list of other symptoms. Specifically, as it relates to this blog, leaky gut can cause the release of mediators that cross the blood-brain barrier, leading to inflammation of the brain. Not only are these mediators inducing inflammation in the brain, but also our intestines are no longer optimally absorbing nutrients as they should, potentially leading to nutrient deficiencies. This is not just some whacky, quaky, made up theory-- research has found this to be accurate. The health of our gut directly affects the health of our brains.
Often referred to as the “second brain,” the gastrointestinal tract (gut) does much more than digest your food and give you that gas that you hope to never have on your first date! Our gut is comprised of trillions of bacteria that truly have minds of their own. The bacteria in our gut are responsible for producing approximately 95% of the body’s supply of serotonin, a neurotransmitter that is responsible for the regulation of mood and sleep. Our dietary choices play a major role in the bacterial environment of our gut, and therefore, the production of neurotransmitters.
As stated by M. Berk et al., "We now know that depression is associated with a chronic, low-grade inflammatory response and activation of cell-mediated immunity, as well as activation of the compensatory anti-inflammatory reflex system." They continue in their discussion to say "A range of factors appear to increase the risk for the development of depression, and seem to be associated with systemic inflammation; these include psychosocial stressors, poor diet, physical inactivity, obesity, smoking, altered gut permeability, atopy, dental cares, sleep and vitamin D deficiency." (emphasis mine)
So, what are the offending foods within the Standard American Diet that are contributing to leaky gut and a poor bacterial environment? Unfortunately, our food supply has been tampered with so much that there is not just one contributing food or chemical.
