Here’s an interesting lazy Friday afternoon read for you. Researchers at WSU Vancouver have found that marijuana helps hunter-gathers fight parasites in their digestive tracts.

Seriously, the more cannabis they smoke, the stronger their immunity to intestinal worms appears to be. Huh… Maybe there’s something to that medical marijuana stuff after all.

The study was led by Ed Hagen, an anthropologist who looked at pot smoking among Aka foragers, a traditional group of pygmy people living in the Congo basin. In a survey, Hagen found that about three-quarters of the 400 adult Aka near the Lobaye River in the Central African Republic smoke marijuana.

Those with cannabis in their systems had fewer helminths, parasitic worms that can infect the intestines. Hagen believes this phenomenon with the Aka may offer some insights into the evolution and history of human drug use.

Much like our evolutionary taste for salt, the study might explain the human attraction to all kinds of drugs.

The findings led Hagen to wonder whether tribes have incidentally used cannabis throughout history to ward off parasites. Whoa… That would be pretty big, since the hunter-gatherer lifestyle accounts for about 99 percent of human history.

Interesting food for thought, for sure. Hagen’s study was published in the American Journal of Human Biology, and it’s gotten some national attention in the last week.

I’ve posted an article about it from WSU News below. Check it out for more details.

– Justin Runquist

Medical marijuana: Hunter-gatherer users have fewer parasites

VANCOUVER, Wash. – Washington State University researchers have found that the more hunter-gatherers smoke cannabis, the less they are infected by intestinal worms. The link suggests that they may unconsciously be, in effect, smoking medical marijuana.

Ed Hagen, a WSU Vancouver anthropologist, explored cannabis use among Aka foragers to see if people away from the cultural and media influences of Western civilization might use plant toxins medicinally.

“In the same way we have a taste for salt, we might have a taste for psychoactive plant toxins because these things kill parasites,” he said

In an earlier study, Hagen found that the heavier tobacco smokers among the Aka also had fewer helminths, parasitic intestinal worms.

He cautions, however, that the studies have their limits. While nicotine has been seen killing worms in livestock, that hasn’t been directly demonstrated in humans. Cannabis kills worms in a petri dish, but researchers have not shown it killing worms in animals, Hagen said.

The Aka are a “pygmy” people of the Congo basin. As one of the world’s last groups of hunter-gatherers, they offer anthropologists a window into a way of life accounting for some 99 percent of human history. They might also offer an alternative hypothesis to explain human drug use.

The prevailing explanation is that recreational drugs “hijack the pleasure centers of the brain,” making people feel good. But by tasting bitter and making us feel sick, they also trigger mechanisms that tell us we’re consuming something toxic.

“So we thought, ‘Why would so many people around the world be using plant toxins in this very “recreational” way?’ ” said Hagen. “If you look at non-human animals, they do the same thing, and a lot of biologists think they’re doing it to kill parasites.”

The issue is significant on at least two fronts, write Hagen and his colleagues, because substance abuse and intestinal helminth infection are “two of the developing world’s great health problems.” Their study appears in the American Journal of Human Biology.

Researchers are unsure when the Aka might have first smoked cannabis or when it arrived on the continent. It may have come with traders from the Indian subcontinent around the first century A.D., but Hagen and his colleagues say it might not have been smoked until European colonization in the 17th century.

Hagen surveyed almost all of the nearly 400 adult Aka along the Lobaye River in the Central African Republic and found roughly 70 percent of the men and 6 percent of the women used cannabis. The polling was supported by bioassays of the men that found high enough levels of THCA, a metabolic byproduct of cannabis’s active ingredient, to indicate that 68 percent of them had recently smoked.

Stool samples collected from the men to gauge their worm burden found some 95 percent of them were infected with helminths. But those who consumed cannabis had a significantly lower rate of infection. A year after being treated with a commercial antihelmintic, the cannabis users were reinfected with fewer worms.

While the Aka deliberately consume a tea of a local plant, motunga, to fight parasitic infections, they do not think of cannabis or tobacco as medicine, Hagen said. This suggests they are unconsciously using cannabis to ward off parasites, he said.

Hagen’s co-authors on the study are Casey Roulette, who did the research as part of his WSU Ph.D., and Pasteur Institute researchers Mirdad Kazanji and Sébastien Breurec. Hagen and Roulette were funded in part by the State of Washington Initiative Measure No. 171.