Next time you get a gut feeling, know that it is, in fact, the feeling of the gut, which is prompting you to make a certain decision. For long, scientists have been conducting research around the connection between the mind and stomach, and it has been proven that the butterflies you feel fluttering in your belly, caused due to nervousness or excitement, have some scientific backing. \u201cA troubled intestine can send signals to the brain much like a troubled brain can send signals to the stomach,\u201d one of the publications by Harvard Medical School opined. It, therefore, does make sense to understand why people following diets that reduce the intake of a certain food category such as carbohydrates or fats have reported to feel low and sad. The dejected feeling is not just a result of the drop in energy levels due to less nutrients in the body, but actually a way of your stomach reacting to lesser than usual proportions it was accustomed to have. According to the Harvard publication, a person's stomach or intestinal distress can also be the cause or the product of serious mental health issues such as anxiety, stress or depression. The connect between the gut and brain is certainly not a new finding or phenomenon. It dates back hundreds of years when scientists in the 19th and 20th centuries thought that depression and anxiety were caused by \u201cpoisons\u201d emananting from the belly. Then almost a decade ago, the linkage between the two was dismissed as mere speculation, but studies around the subject have only gained traction over time culminating into concrete results. Studies have pointed that there are as many nerve endings in our gut as there are in our brain, or maybe even more. The vagus nerve is one of the biggest nerves connecting the belly with the mind. It sends signals in both the directions, according to studies in the field. Scientists call the gut's little brain the enteric nervous system (ENS), which is two thin layers of over 100 million nerve cells lining the gastrointestinal tract from the esophagus to the rectum. \u201cIts (ENS) main role is controlling digestion, from swallowing to the release of enzymes that break down food to the control of blood flow that helps with nutrient absorption to elimination,\u201d according to Jay Pasricha, director of the Johns Hopkins Center for Neurogastroenterology. He noted his findings in a publication on the John Hopkins Medicine website. \u201cThe ENS doesn\u2019t seem capable of thought as we know it, but it communicates back and forth with our big brain\u2014with profound results,\u201d he added. Now with nearly 2,000 unknown bacteria species recently discovered in the human gut in addition to the trillions of microorganisms existing there, the connect only seems to have developed multifold. Researchers at the Wellcome Sanger Institute and the European Molecular Biology Laboratory\u2019s European Bioinformatics Institute (EMBL-EBI) in the UK recently identified thousands of unknown microbes roaming around the human gut. The results, published in the journal Nature, highlight global differences in the bacteria found in the belly and demonstrate that there is lack of data on the microbes from the rest of the world, barring North America and Europe. \u201cComputational methods allow us to understand bacteria that we cannot yet culture in the lab,\u201d said Rob Finn from the European Molecular Biology Laboratory in the journal.\u201dUsing metagenomics to reconstruct bacterial genomes is a bit like reconstructing hundreds of puzzles after mixing all the pieces together, without knowing what the final image is meant to look like, and after completely removing a few pieces from the mix just to make it that bit harder,\u201d Finn added. While research is underway to study what role these newly found bacteria play in our digestive system, the chemical messages that pass between the gut and the brain can certainly be affected by the bacteria, viruses and fungi that live in the stomach. These are known as the \u201cgut microbiome\u201d. Research and experiments carried out on animals have shown that changes in the gut microbiome and inflammation in the belly can affect the brain, resulting in symptoms that look like Parkinson\u2019s disease, autism, anxiety and depression.