Marijuana is ‘genotoxic,’ can increase cancer risk: new paper

Marijuana is ‘genotoxic,’ can increase cancer risk: new paper

You may want to pass on that joint.

A new scientific paper describes cannabis as a “genotoxic” substance that damages genetic information within cells, potentially leading to DNA mutations, accelerated biological aging and cancer.

The authors of the analysis say this genotoxicity can be transmitted to the weed smoker’s offspring via a damaged egg and sperm, possibly making the cannabis risk a problem for future generations.

“The link we’ve described between cannabis use and genotoxicity has far-reaching consequences,” said study co-author Stuart Reece of the University of Western Australia. “This new research shows how genetic damage from cannabis use can be passed down the generations.”


Recreational cannabis is legal in 24 states, and a dozen more states have legalized medical pot.
Recreational cannabis is legal in 24 states, and a dozen more states have legalized medical pot. Getty Images/iStockphoto

Reece’s research is rooted in the power of mitochondria, which are specialized structures within cells that generate the energy needed to fuel cellular processes. It’s already been reported that mitochondria produce less energy if cannabinoids, the active chemicals in marijuana, are present.

Reece and his colleague were inspired by recent research published in Science that found that mitochondrial dysfunction drives chromosomal damage, raising the risk of cancer, accelerated aging and birth defects.

The Science studies were not specifically about marijuana, but Reece was able to glean new, “far-reaching insights” about cannabis use not previously well-understood, including that cannabis causes mitochondrial and genetic damage.


The cancer-cannabis link has been under debate, but marijuana has been shown to increase the risk of testicular cancer.
The cancer-cannabis link has been under debate, but marijuana has been shown to increase the risk of testicular cancer. Getty Images

Cannabis has been shown to increase the risk of testicular cancer, but Reece acknowledges that historically, the “cancer-cannabis link has been controversial.” He blames that dispute on poor study design and a rapid increase in pot potency since the 1970s.

“Whilst cancer is thought to be a rare outcome amongst cannabis-exposed individuals, aging effects are not,” Reece added. “A dramatic acceleration of [biological] age by 30% at just 30 years was recently reported.”

It’s unclear how much marijuana use can cause long-lasting damage.

Reece hopes his analysis, published Thursday in the journal Addiction Biology, “reframes the discussion surrounding cannabis legalization from a personal choice to one that potentially involves multiple subsequent generations.”

Recreational cannabis is legal in 24 states, and a dozen more states have legalized medical pot.

Voters in Florida, North Dakota and South Dakota this month voted against proposals to legalize recreational weed while Nebraska voters opted to legalize it for medical uses.

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