Our Second Brain If you’ve ever had your stomach in knots before speaking in public, then you know the stomach listens carefully to the brain. In fact, according to William Whitehead, PhD, a professor of medicine and an adjunct professor of psychology at the University of North Carolina, the entire digestive system is closely attuned to a person’s emotions and state of mind. People with irritable bowel syndrome often suffer symptoms during times of stress and anxiety, and even perfectly healthy people can have an increase of stomach pain, nausea, constipation or diarrhea during stressful life events. In recent years the link between the nervous system and the digestive system has been recognized. There is a constant exchange of chemicals and electrical messages between the two systems. In fact, many scientists often refer to them as one entity; the brain-gut axis. Therefore, what affects the stomach will directly affect the brain and vice versa. Medications designed to target the brain can also cause nausea, diarrhea, constipation or abdominal upset because the body actually has two brains – one encased in the skull, and a lesser known but vitally important one found in the human gut. Fat-soluble drugs penetrate the gut wall and can injure the natural balance of the digestive system. Antidepressants, benzodiazepines and sleeping pills are all fat-soluble, meaning they dissolve in fat and not water.SSRIs (Selective Serotonin Reuptake Inhibitors) are believed to ease depression by enhancing levels of Serotonin to the brain. But 95% of the Serotonin in the body lies in the digestive system, and diverting the supplies of Serotonin from their natural receptors can increase anxiety, alter sleep patterns, cause sexual dysfunction and adversely affect the cardiovascular region. Balancing the hotbed of Serotonin production in the gut is critical to restoring the balance. Some scientists believe that SSRIs boost Serotonin in the gut and change the signals to the brain, since antidepressants prevent the uptake of Serotonin by cells that should be using it. But Serotonin is calming to the digestive tract. This may explain why some SSRI users experience nausea, stomach upset, constipation, diarrhea, and fluctuations in appetite. GABA receptors for Benzodiazepines and Sleeping Pills are also located in the gut and depress gastrointestinal movement, which can cause constipation. But the continued use of medications that target GABA also increase the level of stress on the body. And in many ways, the connection between stress and the gut may be the most visible brain-gut connection. Chronic stress can result in indigestion, ulcers and a host of uncomfortable symptoms, including colon spasms. This may explain why the gut naturally produces benzodiazepines, to keep the natural state of calm that is necessary for proper functioning. Nearly every chemical that controls the brain is also located in the stomach region, including hormones and neurotransmitters such as Serotonin, Dopamine, Glutamate, GABA and Norepinephrine. The gut contains 100 million neurons – more than the spinal cord. But there are also two-dozen small brain proteins; major cells of the immune system; one class of the body’s natural opiates; and native benzodiazepines. The gut, known as the enteric nervous system, is located in sheaths of tissue lining the esophagus, stomach, small intestine and colon, and plays a key role in human emotions. But few know the enteric nervous system exists, and therefore gut health is often overlooked. Symptoms from the two brains can get confused, and just as the brain can upset the gut, the gut can also upset the brain. The brain signals the gut region by talking to a small number of command neurons, which in turn signal relay neurons that carry messages and control the pattern of activity in the gut. The term Solar Plexus simply refers to the nerves in the abdomen. But these plexuses also contain cells that nourish neurons and are involved in immune response and the protection of the “blood brain barrier” to keep harmful substances away from the important neurons. There are also sensors for sugar, protein, acid and other factors that monitor the progress of digestion, determining how the gut mixes and handles it’s contents.