High altitude adaptation, coca use and health in the andes - Medical Anthropology

Townsend Letter for Doctors and Patients,  Jan, 2003  by Tim Batchelder

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Traditional people living at high altitudes are subject to respiratory, metabolic and other physiological stress. Today, Olympic athletes seek out high altitude locations to train to help increase their lung capacity and cardiac output. In various traditional cultures, certain plants have been used to help adapt to these conditions. In this paper, I discuss one such plant, specifically species of the genus Erythroxylum, popularly known as coca, and the natural source of cocaine.

Overview of Use

The leaves of species of the genus Erythroxylum, known as coca and the source of cocaine, have been chewed (ie. formed into a quid that is tucked between the teeth and sucked to extract the juices) by people in Andean South America for 5000 years (Plowman: 1984, 1986). Millions of people, especially in Peru and Bolivia, chew 4-5 grams of coca leaf together with one of several alkalines, at regular intervals throughout the day and their adult lives. Coca chewers also consume the leaves in the form of a hot infusion (mate de coca) and millions of non-chewers consume them only in this form. (Carter et al. 1980, Burchard: 1976). The fact that it is a persistent, pervasive plant that forms the natural source of cocaine has resulted in prohibitionist movements, yet anthropological research shows that this plant -- consumed in its traditional cultural context and environment -- may be quite beneficial to health and high altitude adaptation.

Blood Sugar Control

Bolton (1976:632) points out that he has found that coca chewing may be a response to hypoglycemia which occurs due to the difficult conditions of high altitude, physical labor under which many traditional Andean people work. In 1972 he proposed the hypothesis that coca chewing is causally related to patterns of glucose metabolism commonly found among Andean people in which blood glucose levels rise rapidly following a meal and then drop rapidly in many cases to a point below the fasting level. Individuals with this metabolic pattern are more likely to experience hunger again shortly following a high carbo meal. Chewing coca buffers this drop just as chewing coca in the absence of eating raises glucose levels especially when they may be depleted due to strenuous exercise (hence coca breaks during hard work). Chewing coca will keep blood glucose elevated above fasting levels for more than four hours. The metabolic functioning of the non-chewers may approximate more normal patterns of glucose homeostasis. Hypog lycemic subjects consumed more coca than non-hypoglycemics (Bolton 1976: 632).

Similarly, Gray (in Moran) suggested that low levels of glucose and problems of carbohydrate mal-absorption are widespread health problems in highland Peru and are related to under-nutrition, especially a lack of protein (Gray: 1973: 70-71). Gray further points out that atrophine, an amino alcohol found in coca, increases contact time between carbohydrates and intestinal mucosa (1973: 122-123). Burchard noted that coca is chewed often before and after meals, which relaxes the small intestines and facilitates absorption (1976: 266-267 in Moran).

Temperature Regulation

Coca use also influences heat production (Picon-Reategui 1976). Coca induced intestinal absorption of food may help individuals meet the increased cost of keeping warm in a cold environment, of heavy work schedules, and the needs of pregnancy, lactation, and growth (Picon-Reategui 1976: 235 in Moran). Residents of Nunoa, Peru, living at altitudes over 13,000 feet (4000 meters) use coca to aid in body heat conservation by vasoconstriction (Hanna: 1974 in Moran).

Caloric Deprivation

Humans evolved under conditions of periodic food scarcity which modern industrial people are unfamiliar with. Periodic food restriction is shown to be beneficial to health. However, to help adapt to the psychological difficulty of these fasts, certain plants are used traditionally. Leonard (1989, Leonard and Thomas 1989) point out that coca use may represent one of many household level responses to seasonal energy stress which occur in Nunoan households as food shortages during the last part of the rainy season (Feb to April). During this time adolescents and adults are subjected to the greatest levels of nutritional stress while children under the age of 13 are relatively protected. Coca chewing in these households begins at about age 14-15. Thus there seems to be a connection between coca chewing and caloric deprivation.

Bolivian men, Burchard points out, go for days without food, sustaining themselves by chewing coca. Early visitors to the Tahitians and Fijians noted they go for three days without food on trips to the interior and are in exemplary health. In the Pacific Kava acts as an appetite suppressant in men who drink it regularly (Pollock 1991). Strickland suspects that coca chewers have greater endurance at higher levels of work output than non-chewers.

Wilson points out that the moderate amount of coca consumed could cause vasoconstriction and thus reduce feelings of cold at high latitudes and reduce sensation of hunger through suppression of peristalsis. Burkill (1966) notes that the Spanish considered Indian use of the leaves as similar to Chinese use of opium and tropical Asian chewing of betel (areca nut). All these substances are stimulating and addictive but generally not harmful in the small quantities, Wilson states.