– We have this thing called the xenobiome, and the xenobiome is basically the comprehensive chemical environment in which the liver evolves. So our liver, over millennium has evolved by becoming familiar with various chemicals in the environment; specifically, plant compounds, plant chemicals. So not everything in plants is good for us or safe. Every plant manufactures it’s own version of pesticides, and these compounds that are in the plants are potentially toxic to insects specifically and also to us. And what has happened is over time, we have co-evolved, some like to use the term, we have coherently coupled, with plants over hundreds of thousands of years. We have a long standing historic interaction with the plant world. And one of the things with plants is that we would try a little bit of them and see how it tasted, and if there was some bitter in there, that was a signal that there’s possibly something potentially toxic in this plant and I shouldn’t eat too much of it. But every time we consumed a little bit of a plant, we were introducing chemicals, phytochemicals, into our physiology that our liver had to figure out what to do with. So over time the liver has developed specific detoxification enzymes, detoxification pathways that were designed to metabolize these plant compounds, these xenoestrogens and eliminate them to reduce the toxic burden in our physiology. So as we developed this relationship with plants we also developed this bitter taste sensation, this bitter taste receptor that was designed to give us really good information about whether plants are safe or not.