92 Coca
quantity for hours, much like chewing gum. Coca is a local anesthetic and
numbs the mouth when a person chews coca leaves. Lime (the mineral, not
the fruit) may be added to improve the body’s absorption of cocaine from the
leaves. Habitual leaf chewers routinely receive a daily cocaine dose of 0.25
grams spread over several hours. Coca tea or the leaves themselves are used
to aid digestion, reduce gastrointestinal colic, fight asthma, soothe vocal cords
(laryngitis), relieve stress and elevate mood, alleviate cold and thirst, produce
sweat, and fight motion sickness. Milk with coca has been used against colic
and diarrhea in babies. Coca cigarettes have been used to treat both asthma
and colds. Proposals have been made to produce coca lozenges and chewing
gum to make the natural product available in formats more familiar to persons
coming from a European heritage.
Habitual coca chewing interferes with the body’s insulin and thereby tends
to raise blood sugar levels. That finding should interest diabetic chewers but
is also relevant to persons using leaves at high altitudes (common in the An-
des) because the reduced oxygen supply at upper elevations tends to lower
blood sugar. Habitual coca use apparently compensates for that effect. Blood
sugar tends to decline during exercise; coca can prevent that decline, and
scientists suspect that coca can increase the body’s effective use of blood sugar
during exercise.
Coca leaves improve a person’s access to stored energy sources in the hu-
man body and thereby increase capacity for physical labor. During the nine-
teenth century such qualities attracted notice in Europe, but suggestions that
coca be used in industrial and military labor were apparently ignored. In the
1970s a sample of Argentine miners showed that 65% chewed coca leaves
every day, and another 14% used leaves less often. The more physical power
and endurance required for a particular job, the more likely that a miner used
coca leaves each day. One study of coca found the typical stimulant actions
of raising pulse rate and blood pressure but also found that coca had a more
unusual effect of decreasing the volume of blood plasma—a condition nor-
mally associated with bleeding or with not drinking enough fluids. This con-
dition interferes with proper blood circulation during physical exercise, but
centuries of experience suggest that coca-chewing laborers get along well
enough nonetheless. The study just referred to involved habitual chewers of
coca; occasional chewers may not experience the same results. For example,
in another study scientists concluded that regular chewers had more access to
energy stored in body fat but that occasional chewers did not and also con-
cluded that occasional chewers would not show the same improved endurance
during physical exercise that is demonstrated by habitual chewers. One in-
vestigator has concluded that coca improves endurance but does not otherwise
help physical labor (a person cannot lift more or run faster).
Like many stimulants, coca reduces feelings of hunger and can thereby re-
duce food intake. The appetite suppressant effect is slight, however, simply
helping a person to get by more comfortably when food is scarce. Coca chew-
ers exhibit robust appetites when victuals are plentiful, and coca preparations
can even be an element of meal-taking. Some research suggests that under
low atmospheric pressure coca can improve the body’s metabolism of carbo-
hydrates and thereby improve nutrition of users. Coca itself is a good source