Does turmeric have anticancer properties? A recent literature review examines whether turmeric can be useful in treating cancer. The authors conclude that this could be the case, but note that there are many challenges to overcome before arriving at the clinic.
Turmeric is a member of the ginger family. Native to India and Southeast Asia, people have used turmeric root to flavor their food for thousands of years.
Historically, people have associated turmeric with healing properties. Even now, some hail turmeric as a panacea for all ailments. Recently, its popularity has increased, as evidenced by the recent fashion of turmeric latte. However, as with many things in life, reality rarely matches the hype.
The turmeric chemical of most interest to medical researchers is a polyphenol called diferuloylmethane, which is more commonly known as curcumin. Most research on the potential powers of turmeric has focused on this chemical.
Over the years, researchers have pitted curcumin against a number of symptoms and conditions, including inflammation, metabolic syndrome, arthritis, liver disease, obesity, and neurodegenerative diseases, with different success levels.
Most importantly, scientists have focused on cancer. According to the authors of the recent review, of the 12,595 articles that researchers published on curcumin between 1924 and 2018, 37% focus on cancer.
In the current review, which appears in the review Nutrients, the authors have mainly focused on the cell signaling pathways that play a role in the growth and development of cancer and how turmeric may influence them.
Cancer treatment has improved dramatically in the past few decades, but there is still a long way to go before we can beat cancer. As the authors note, “the search for innovative and more effective drugs” remains vital work.
In their review, the scientists paid particular attention to research involving breast cancer, lung cancer, blood cancers and cancers of the digestive system.
The authors conclude that “curcumin represents a promising candidate as an effective anticancer drug for use alone or in combination with other drugs”.
According to the review, curcumin can influence a wide range of molecules that play a role in cancer, including transcription factors, which are essential for DNA replication; growth factors; cytokines, which are important for cell signaling; and apoptotic proteins, which help control cell death.
In addition to discussions surrounding the molecular influence of curcumin on the cancer pathways, the authors also address potential problems associated with the use of curcumin as a drug.
For example, they explain that if a person takes curcumin by mouth – in a turmeric latte, for example – the body quickly breaks it down into metabolites. As a result, the active ingredients are unlikely to reach the site of a tumor.
With that in mind, some researchers are trying to devise ways to deliver curcumin into the body and protect it from metabolism. For example, researchers who encapsulated the chemical in a protein nanoparticle has shown promising results in the laboratory and in rats.
Although scientists have published a large number of articles on curcumin and cancer, there is a need for more work. Many of the studies in this review are in vitro studies, which means that researchers have conducted them in laboratories using cells or tissues. While this type of research is vital to understanding what interventions may and may not influence cancer, not all in vitro studies translate to humans.
Relatively few studies have tested the anti-cancer properties of turmeric or curcumin in humans, and studies in humans have been small. However, apart from the difficulties and limited data, curcumin still has potential as an anti-cancer treatment.
Scientists continue to work on the problem. For example, the authors mention two ongoing clinical trials, both of which aim to “assess the therapeutic effect of curcumin on the development of primary and metastatic breast cancer, as well as to estimate the risk of adverse events”.
They also refer to other ongoing human studies that are evaluating curcumin as a treatment for prostate cancer, cervical cancer and lung nodules, among other diseases.
The authors believe that curcumin belongs to “the most promising group of natural bioactive compounds, particularly in the treatment of several types of cancer”. However, their praise for curcumin as an anti-cancer hero is tempered by the realities that their reviewer uncovered, and they end their article on a low note:
“[C]urcumin is not immune to side effects, such as nausea, diarrhea, headache and yellow stools. In addition, it has shown low bioavailability due to poor absorption, rapid metabolism and systemic elimination which limit its effectiveness in the treatment of diseases. More studies and clinical trials in humans are needed to validate curcumin as an effective anticancer agent. “