Coca Chewing and High-Altitude Stress: Possible Effects of Coca Alkaloids on Erythropoiesis [and Comments and Reply

Abstract

Andean Indians who chew coca seek to alleviate symptoms of hunger, thirst, fatigue, cold, and pain. A complete explanation of coca's use should account for these motives. The distribution of coca chewing in the Andes is shown to parallel that of polycythemia. Coca chewing is more common in higher altitudes, with men consistently chewing more than women and children, and chewing is especially common amongst mineworkers. Since androgens stimulate erythropoiesis and estrogens depress it, men at any given altitude are also more susceptible to polycythemia than women. Mineworkers are polycythemic because of silicosis. The debilitating effects of viscous blood from polycythemia are more consequential than the increased ability of the blood to transport oxygen. Clinical manifestations of polycythemia include fatigue and headache, some of the very symptoms which coca chewers seek to alleviate by their use of the drug. A physiological mechanism is suggested by which cocaine and ecgonine, the active ingredients in the coca leaf, may suppress erythropoiesis, thereby helping to alleviate these symptoms. Since evidence exists that, when nutrition and disease are taken into account as influencing factors, coca chewers have lower hematocrits than controls, it is likely that coca use provides specific medicinal relief for chronic polycythemia.