The gut-thyroid connection is one of the most important and overlooked aspects of healthy thyroid function. Did you know that many diseases can be traced to a breakdown in the gastrointestinal tract? 70 percent of your immune system resides in this area – your gut, and the GI tract has many important functions for your health including digestion, nutrient absorption, elimination, detoxification, hormone metabolism and energy production. 99% of the neurotransmitters in your body are actually created in the intestine (part of your GI tract), and every brain chemical known as a neurotransmitter is found there. This means the GI tract, or gut, plays a very important role in achieving optimal thyroid health.