227. Brain-Gut Axis
During evolution, cyanobacteria absorbed carbon dioxide and released oxygen making our existence possible. They evolved as chloroplasts which adapted to life inside plant cells enabling photosynthesis to give us food. The same is the case with the mitochondria, the powerhouse of the human cell, which adapted to life inside the cell. Both mitochondria and chloroplasts still possess their own DNA. Similarly, our intestine hosts hundreds of species of bacteria and fungi. They are responsible for the digestion of our food and providing us with nutrition. Current research indicates that they even control our behaviour through the brain-gut axis (vagus nerve) as 500 million neurons (half the percentage of the brain) are located in the intestine. This background helps us understand the following verses. Krishna says, "The food that people prefer is also threefold, as also sacrifice (yagna) , austerity (tapah) and donation (danam) (17.7). Foods which increase longevity, pu