Regular stoners may have a higher risk of developing heart disease or having a heart attack, according to a new study published in the journal Cell. Researchers have found that smoking a joint triggers a rapid increase in pro-inflammatory compounds that can harm blood vessels — but a soy molecule can help alleviate that damage.
Despite the growing interest in medical cannabis, the drug’s effects on cardiovascular health are largely unknown. To clarify the matter, the study authors analyzed the medical records of 157,331 people in the UK, including 34,878 who admitted to using cannabis.
Of these, 11,914 reported taking the drug more than once a month. Overall, these monthly users were 16% more likely to have a heart attack and were also more susceptible to premature heart attacks before age 50.
Digging a little deeper, the researchers analyzed blood samples from 18 people immediately after smoking a joint, finding that pro-inflammatory cytokines increased within 90 minutes. These compounds are strongly implicated in atherosclerosis, the thickening of blood vessel walls due to the buildup of fatty plaques.
After applying THC – the psychoactive ingredient in cannabis – to isolated human endothelial cells, the authors found that the compound also suppressed antioxidant genes, further contributing to inflammation in the lining of blood vessels.
Commenting on these findings, study author Mark Chandy explained that “As more states legalize the use of marijuana, I expect we will begin to see an increase in heart attacks and strokes in the coming years,” adding that “THC exposure initiates a harmful molecular cascade in blood vessels.”
The researchers found that the negative effects of THC on blood vessels are mediated by the cannabinoid receptor 1 (CB1). Researchers have attempted to neutralize THC activity using CB1 antagonists, which block the receptor, although most of these compounds are unsuitable for use due to their psychiatric side effects.
However, using machine learning techniques to track a large database of CB1 antagonists, a compound called genistein was identified as a potential solution to the cardiovascular problems generated by THC. Found in soy, genistein has a very limited ability to penetrate the brain, meaning it shouldn’t produce any of the harmful side effects associated with other CB1 blockers.
To investigate the compound’s effectiveness, the team fed mice that were bred to have high cholesterol a high-fat diet. Adding a standard dose of THC to the rodents’ diet caused them to develop larger plaques inside their blood vessels, but genistein treatment prevented this increase in plaque size.
“We saw no blockage of THC’s normal analgesic or sedative effects in mice that contribute to marijuana’s potentially useful medicinal properties,” Chandy said. “So genistein is potentially a safer drug than previous CB1 antagonists. It’s already used as a nutritional supplement and 99% of it stays outside the brain, so it shouldn’t cause these specific adverse side effects.”
While the use of THC and genistein has yet to be tested in humans, researchers suggest that this combination may allow medical cannabis users to continue to enjoy the drug’s beneficial effects without increasing their susceptibility to heart disease.