Cannabis use may be associated with a range of positive health benefits, including decreased obesity, inflammation and diabetes risk, as well as a 10% reduction in cancer rates. These are the findings of research recently published in the journal Cannabis and Cannabinoid Research.
This research highlights the fact that even though cannabis smoke contains known carcinogens similar to tobacco smoke, it appears the anti-tumor effects of cannabis may not only cancel out any harmful effects, but provide some protection against certain cancers.
The study even goes on to suggest that if the 10% decrease in cancer risk indicated by the current analysis is accurate (which it might not be), then cannabis use would prevent as many as 23,800 to 35,700 cancer diagnoses and 8498 to 12,747 cancer deaths each year in America.
Conducted by Professor Thomas M. Clark at Indiana University in the U.S, the meta-analysis (a study that assesses the results of previous research to derive conclusions about that body of research) reviewed 34 studies that explored the relationship between cannabis use and the risk of developing certain types of cancers.
What he found was that cannabis use was negatively associated with various types of cancers, although not testicular cancer – for which risk was slightly increased, albeit by a non-significant amount. Cannabis use was most strongly correlated with a reduced risk of developing cancers of the head and neck.
However, the study also makes clear that there is “low confidence in this result due to high heterogeneity and a paucity of data for many cancer types.”
When dissecting the body of research, Prof. Clark also found decreased obesity in cannabis users, as well as decreased inflammation, improved insulin resistance and decreased risk of diabetes.
The reduction in obesity among cannabis users probably plays a part in decreased cancer risk as obesity is a well-established risk factor for many cancers, the study suggests.
Additionally, chronic inflammation is strongly associated with both obesity and with the initiation and progression of cancer.
The study states: “Cannabis use may directly inhibit inflammation at the cellular level, and in addition, indirectly reduces inflammation by decreasing BMI and risk of obesity. Both actions should decrease cancer risk. This effect would be offset if inflammatory responses are desensitized with chronic use.”
Furthermore, cannabis use is associated with reduced risk of diabetes, reduced fasting insulin levels, and reduced insulin resistance. Diabetes, elevated insulin and insulin resistance are all associated with greater cancer risk, and faster growth and aggressiveness, and thus increased mortality, from certain cancers.
It was also noted that cannabis can help regulate the gut microbiome and even prevent obesity in mice fed a high fat diet.
Direct antitumor properties of Cannabis
Perhaps the main action of cannabis reducing cancer risk is the direct antitumor properties of cannabis compounds, including psychoactive and non-psychoactive cannabinoids as well as flavonoids and possibly terpenes.
“Cannabinoids inhibit tumor initiation, metastasis, vascular adhesiveness, tissue invasiveness, and angiogenesis, while selectively stimulating apoptosis of cancer cells. They thus, by multiple mechanisms, inhibit all stages of cancer initiation, development, growth, and spread.
“As a result, in laboratory studies and animal models, cannabinoids destroy tumors while leaving surrounding cells unharmed. In laboratory studies, cannabinoids inhibit gliomas, thyroid epithelioma, lymphoma, neuroblastoma, and carcinomas of the oral region, lung, skin, uterus, breast, prostate, pancreas, and colon.”
The study concluded: “The current analysis suggests an association of cannabis use with a substantial decrease in risk of non-testicular cancers, with moderate effect size, and a non-significant increase in risk of testicular cancer, with negligible effect size. This suggests that cannabis use may substantially decrease the death rate from cancer in the United States.”
While it’s worth noting that the data used in this review are epidemiological, rather than experimental, and thus can show only association but not causation, it speaks to the need for the widespread use of cannabis and the relaxation of laws surrounding the plant.
Not only can cannabis reduce inflammation, diabetes, obesity and cancer risk (among other health benefits), it is well known to be extremely safe – safer than many pharmaceuticals.
So safe, in fact, that even when smoked – which produces known carcinogens – the positive effects outweigh the harm. If vaporised or consumed in the form of an oil, could cannabis confer even more protection? It’s likely.