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The center of our nervous system – the brain – is one of the last frontiers of the human anatomy. Our nervous system is said to hold about a trillion neurons (nerve cells), with each neuron having up to 10,000 branches that create complex networks within the brain and communicate with cells throughout the body. It is important to understand that the brain does not exist in isolation, but interacts with and is affected by almost every other gland, organ, and function in the body. The belief that the brain represents purely mental processes and the body represents purely physical processes, a belief rooted in the dualism of Western culture, minimizes the myriad of bio-chemical-electro-magnetic connections that link cells to human consciousness.
We tend to think of the brain as composed of electrical circuits, with “wires” called nerves and neural pathways that connect the brain’s control centers to the rest of the body. However, only recently have scientists come to appreciate what we may now call the “chemical brain” which represents a second nervous system, one that operates on a much longer time scale, over much greater distances. “Especially difficult to accept was that this chemical-based system was one indisputably more ancient and far more basic to the organism. There were peptides such as endorphins, for instance, being made inside cells long before there were dendrites, axons, or even neurons – in fact, before there were brains.” 1
The brain also acts as an endocrine gland, secreting informational molecules that affects organ systems throughout the body, via the bloodstream. In turn, the brain is affected by numerous informational molecules secreted by other glands and cells. Especially peptides, large chains of amino acids, created by the digestive system can operate as informational molecules. For example, some of the newest neurotransmitters, cholecystokinin and vasopeptide, were first discovered in the intestines and gall bladder. Our intestines produce even greater quantities of serotonin than our brains. (That is why people who take a selective serotonin reuptake inhibitor [SSRI] like Prozac, for psychiatric reasons, commonly experience side-effects in the stomach and intestines.) This has lead some investigators to talk about a “Gut-Brain” connection.
The Protective Blood-Brain Barrier
“A blood-brain barrier exists between the blood vessels (capillaries) that course through the brain tissue and the extracellular space within the brain. It prevents certain molecules in the blood from entering the tissue space of the brain itself. It is thought that the major portion of the “barrier” lies in the tight junction between cells (endothelial cells) that line the capillary walls. Blood vessels in other parts of the body have relatively large spaces between the cells that allow passage of even larger molecules.”
“The brain receives the same blood that flows through the body. Therefore, it is exposed to high concentrations of chemicals in the blood, both from metabolism and from the diet. Some of these chemicals are quite toxic to the brain. . . . The blood-brain barrier excludes some substances and allows others free passage. In general, the amino acids are carefully regulated because so many serve as neurotransmitters, or transmitter precursors. . . . Without careful control of these substances, each time we ate a meal our brains would go berserk.”
“However, the barrier is not perfect. In fact, some parts of the brain never develop a barrier system at all. For example, the hypothalamus, the circumventricular organs, the pineal, and a small nucleus in the brain stem called the locus ceruleus, are without barrier protection. There is also evidence that the barrier is broken down or at least partially malfunctioning under certain conditions. For instance, strokes temporarily cause the barrier to break . . . Head injury, degenerative diseases, infections, and a multitude of other injuries can also cause this protective system to fail.”
— R Blaylock in Excitotoxins: The Taste that Kills. 2
During infancy and childhood, the blood-brain barrier is less developed than it will be at maturity, which means that the brains of infants and children are generally more vulnerable to toxins than are the brains of adults. Furthermore, it is likely that children with weakened immune systems, poor nutritional status, allergies, toxic exposure, or neurodevelopmental delay may have less effective blood brain-barriers and be even more susceptible to various brain insults. Dietary management, along with avoidance of toxic exposure, might offer significant therapeutic benefits for these individuals.
