The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Nicotine — candy or cure? A longitudinal study of smoking vs helminth reinfection among African hunter-gatherers


1Department of Anthropology, Washington State University, 2Institut Pasteur, Bangui Central African Republic, 3Department of Anthropology, California State University, Sacramento

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According to neurobiologists, the widespread use of tobacco, and the resulting global epidemic of lung cancer and heart disease, are explained by the effects of nicotine on the mesolimbic dopamine system (MDS), also known as the reward system. The MDS is believed to have evolved to reinforce behaviors leading to natural rewards such as food and sex. Nicotine increases dopaminergic transmission in the MDS, thus reinforcing tobacco consumption. Because nicotine is not thought to be responsible for cancers or other chronic tobacco-related health problems, it has been conceptualized more-or-less as ‘sugar for the brain.’

Nicotine, however, evolved to defend tobacco plants from herbivores, and has a toxicity comparable to hydrogen cyanide. Moreover, in humans and laboratory animals, it activates a suite of toxin-defense mechanisms, including bitter taste receptors, nociceptive neurons, aversion, and conditioned taste avoidance, which should deter, not encourage, tobacco consumption.

Although nicotine is harmful to tobacco consumers, it is potentially even more harmful to their parasites. We report further tests of the hypothesis that the 'recreational' use of tobacco and other plant drugs is motivated, in part, by an evolved propensity to self-medicate against infections by helminths and other macroparasites. Worm burden, nicotine exposure, and control variables were measured in 68 Aka foragers from the Central African Republic. Study participants were then treated with albendazole, a commercial anthelmintic. After 12 months, worm burden and nicotine exposure were remeasured to test the hypothesis that heavier smokers would exhibit a lower rate of reinfection by helminths.

This investigation was supported in part by funds provided for medical and biological research by the State of Washington Initiative Measure No. 171.

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