Our inability to produce a chemical present in every other primate may be linked to a series of chronic diseases. Roger Highfield explains more What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California. Not so rare: a molecule absorbed by eating red meat has been linked to inflammation and auto-immune illnesses Not so rare: a molecule absorbed by eating red meat has been linked to inflammation and...