The medical benefits of cannabis have been touted for thousands of years. Even in the U.S.— before the days of Reefer Madness—cannabis was an active ingredient in many medications.
Today, inspired by regional legalization, researchers are finding new ways cannabis can restore health, from mitigating seizures in children with epilepsy to helping to fight cancer. But on the other side of the world, away from civilization and legalization debates, researchers have discovered that a West African pygmy tribe has been inadvertently relying on the sticky-icky to combat parasitic infections.
Anthropologists from Washington State University studied the Aka population in the Congo basin to gain a better understanding of how a group of people cut off from society might use certain plant toxins, specifically marijuana, as medicine.
In order to do this, researchers collected self-reported data of cannabis use from all 379 members of the Aka population residing in the basin at the time. They found that 70.9 percent of males and 6.1 percent of females used cannabis. (Women said they don't use the drug as much because they believe it will harm a fetus.)
Since female use was so low, they decided to focus on the men. Researchers then studied 62 Aka males, collecting stool samples every other day for about six days, over the course of three years. Urine and saliva were also collected.
Biomarkers for THC (known as THCA) were found in the 68 percent of the men, suggesting they had recently smoked. According to researchers, the THCA levels in the Aka were comparable to if not higher than chronic users in the West.
Researchers didn't just measure for marijuana, though; they also analyzed stool samples for the presence of helminths—parasitic infections like hookworms and roundworms. Ninety-five percent of the men were, in fact, infected.
However, they found that the men who smoked cannabis had fewer parasites than men who did not. "Worm burden was significantly negatively correlated with THCA," write the researchers, "which is consistent with the chemotherapeutic hypothesis of drug use." Referring to the fact that cannabis is toxic to parasites.
Not only that, the men who smoked more cannabis were less prone to reinfection after being treated with an antihelmintic one year later.
As the researchers point out, the Aka men do not associate cannabis use with anti-parasitic properties—they are unconsciously self-medicating. Extrapolating on that idea, the researchers believe that humans' cravings for certain substances may not just be about pleasure but biology.
"In the same way we have a taste for salt, we might have a taste for psychoactive plant toxins, because these things kill parasites," said Ed Hagen, co-author on the study, in a press release.
In other words, as humans, it's possible we're drawn to certain plants for health reasons—which might explain why humans have had a relationship with cannabis for thousands of years.
"Although the conventional view is that drug abuse impairs immunity, thus increasing susceptibility to infection , if recreational drug use is explained (at least in part) by the drugs’ antiparasitic properties, this would suggest that the immune system plays a key role in regulating drug use," the authors write in the study.
Indeed, the Aka's rate of marijuana use (38.6 percent when averaging men and women) is much higher than the rest of world's (3.9 percent of the global population aged 15 to 64 used cannabis in 2011), despite the expense for users. According to the study, Aka men make roughly $0.50 a day and a cannabis cigarette costs $0.10. The men end up spending roughly half their wages to feed the habit.
Taryn Hillin is Fusion's love and sex writer, with a large focus on the science of relationships. She also loves dogs, Bourbon barrel-aged beers and popcorn — not necessarily in that order.