Although indulging in a cannabis-infused brownie or gummy may seem like a harmless way to enjoy the effects of THC, recent research indicates a concerning link between consuming edibles and cardiovascular health issues. A study led by Matt Springer, a cardiovascular researcher at the University of California, San Francisco (UCSF), has revealed that the consumption of THC edibles could potentially worsen cardiovascular conditions over time, similar to the effects observed in chronic tobacco smokers.
Published on May 28 in the journal JAMA Cardiology, this groundbreaking study challenges the widespread belief that marijuana is safe for heart health. Dr. Robert Kloner, director of cardiovascular research at Huntington Medical Research Institutes in Pasadena, California, emphasized that although there is no complete consensus in the scientific community regarding the health effects of cannabis, the findings from UCSF add to a growing body of evidence linking cannabis use to increased risks of cardiovascular events, including heart attacks and strokes. This risk is particularly pronounced in individuals with pre-existing conditions such as coronary artery disease, high blood pressure, or diabetes.
To investigate the effects of cannabis on vascular health, Springer and his team recruited 55 adult participants, dividing them into three distinct groups: cannabis smokers, THC edible users, and non-users. The study specifically targeted habitual cannabis users who reported consuming the substance at least three times a week through their preferred method. The strict recruitment criteria, though resulting in a smaller sample size, allowed researchers to eliminate confounding factors such as tobacco use or existing health conditions.
To evaluate the vascular function of each participant, the researchers employed a method that involved temporarily blocking blood flow to the brachial artery in the upper arm using an inflatable cuff. Utilizing ultrasound imaging, they measured the artery's diameter before and after releasing the pressure, quantifying the percentage change in diameter from baseline measurements. According to Springer, this test provides insight into future cardiovascular health, as an inability of blood vessels to dilate properly can indicate a higher risk of serious outcomes, including heart attacks.
The results were striking: participants who did not consume cannabis exhibited an average vessel dilation of 10.4%, while cannabis smokers showed a decreased dilation of 6.0%, and those consuming edibles had an even lower average of 4.6%. These findings mirror outcomes from previous studies on chronic tobacco smokers, suggesting that increased cannabis use correlates with a more significant impairment in vascular function.
To further understand the underlying mechanisms at play, the researchers conducted laboratory analyses of blood samples from participants. They focused on the effects these samples had on endothelial cells—critical components of blood vessels responsible for releasing compounds that promote vascular dilation, such as nitric oxide. Interestingly, when blood samples from cannabis smokers were tested, they inhibited the production of nitric oxide in endothelial cells stimulated by vascular endothelial growth factor (VEGF). In contrast, blood from edible consumers and non-users did not exhibit this negative effect.
This suggests that the effects of cannabis smoke and ingested THC on cardiovascular health may operate through different biological pathways. These insights align with previous studies indicating that even secondhand cannabis smoke can impact vascular function.
While this study establishes an association between cannabis use and impaired vascular function, Springer cautioned that further research is necessary to determine causality and the full scope of cannabis's impact on cardiovascular health. Notably, the study focused only on habitual cannabis users, which means that individuals who consume cannabis less frequently might not experience the same vascular issues.
As cannabis becomes increasingly legal and accessible across various states, the urgency for comprehensive research into its health effects grows. Dr. Kloner points out that despite its legal status in many areas, the federal prohibition of cannabis continues to hinder scientific studies, complicating our understanding of its health implications.
