In this study from 2019, researchers investigated the connection of kava and cancer and it could be protective against certain types of cancer. This is a systematic review that identified, assessed and analyzed related studies to gain a better idea of how the protective components of kava work against cancer cells. The specific components they are interested in are kavalactones, chalcones, cinnamic acid derivatives and flavanones.
What they did
Researchers conducted an in depth systematic review of studies that investigated kava and cancer, particularly the anticancer effects of kava compounds. They further looked at the potential for these compounds to be used to promote cell death (known as apoptosis) of cancer cells. They laid out specific inclusion and exclusion criteria to be sure they found the most relevant studies. Studies that were included looked at the different components of kava on cancer cells, how they work, (the mechanism of action) and the potential clinical benefits they have for cancer patients.
How they did it
They used three of the largest medical databases to find relevant studies. The excluded studies there were poorly done or that left out key information. The goal was to include the highest quality studies they could find. The authors collected information on the type of cancer studied, the specific kava components studied, experimental designs, how the study was done, outcomes, and findings related to the effects of Kava compounds on cancer cells. Authors evaluated studies for quality to be sure they had good quality data for the review.
What they found
The studies included all suggested that kava and specifically kavalactones, have potential anticancer benefits for certain types of cancers.
In oral cancers, certain types of kavalactones were seen to trigger cell death in cancer cells and slow down cancer cell growth. These effects were linked to the changes of key pathways that are responsible for controlling cell survival and growth. A similar effect was seen in colon cancer cells. Certain kavalactones had the ability to disrupt the growth and division of cancer cells through affecting how cells progress and caused cell death. In breast cancer cells, the compounds of kavalactones appear to target molecules that target cell movement and further growth of cancer cells. They can reduce the movement and invasion of cancer cells, decreasing the spread and impact of cancer cells to other parts of the body. And finally, the researchers found that certain kavalactones might prevent the growth and spread of prostate cancer cells and trigger cell death. They may also affect certain pathways that contribute cancer cell survival, in turn disrupting this cycle.
What it means
This review suggests that kava and its active components kavalactones could be promising treatment for preventing or reducing the spread of certain cancers. Kavalactones showed a variety of therapeutic effects that could have a significant implant on how we treat and fight cancer. However, this is a new field of study, and while the results were definitely promising, the researchers noted that more studies need to be done on kava and cancer to get a better understanding of how these compounds work against cancer cells and the clinical use they could have.
Link to original paper
Celentano, A., Tran, A., Testa, C., Thayanantha, K., Tan-Orders, W., Tan, S., Syamal, M., McCullough, M. J., & Yap, T. (2019). The protective effects of Kava (Piper Methysticum) constituents in cancers: A systematic review. Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology, 48(7), 510–529. https://doi.org/10.1111/jop.12900