(CanadianBusiness) - What is it about wine, especially red wine, that makes as much as a third of humanity unable to drink it without getting a headache? We're not talking about a hangover here. Drinking just one glass can trigger immediate discomfort, raise blood pressure or morph into a days-long migraine. Until the 1980s, red wine headache, as the condition has become known, was put down to alcohol intolerance—yet those afflicted could consume beer or spirits without feeling pain. Perhaps the greatest injustice is that it even affects people who love the taste of wine and the way it pairs with food.