When Danish scientist Henrik Dam fed a cholesterol-free diet to baby chicks in his lab about 90 years ago, he noticed excessive bleeding in some of them. It did not stop after he replaced the cholesterol. Dam ultimately concluded the bleeding was related to a “depletion of an anti-hemorrhagic compound,” which he called vitamin K (for “koagulation,” as spelled in Danish). For that discovery, Dam won the Nobel Prize in Physiology or Medicine in 1943.